Vitamins and Hormones|ISC Chemistry Project|Biswajit Das

Vitamins are essential organic compounds that the body needs in small amounts to function properly, while hormones are chemical messengers that regulate various physiological processes in the body.

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Introduction

Food is our basic need. It nourishes our body and maintains our health. It gives us energy that is required for every action of ours including our participation in games and sports. The various food items that we consume constitute our diet. Diet may be defined as the total amount of different variety of food items consumed by a person during a day. Food is our basic need. It nourishes our body and maintains our health. It gives us energy that is required for every action of ours including our participation in games and sports. The various food items that we consume constitute our diet. Diet may be defined as the total amount of different variety of food items consumed by a person during a day. Our diet contains many food items which are obtained from different sources.

The food may be obtained from animal or vegetable sources. We already know that food comprises constituents like proteins, carbohydrates, fats and supplementary substances such as minerals, vitamins and water that are vital for life. These constituents are known as nutrients. For proper functioning of our body we need to consume body building foods (e.g. milk, meat, poultry, fish, eggs, pulses, groundnuts); energy giving foods (e.g. cereals, sugar, roots, fats and oils); and protective foods (e.g. vegetables, fruits).

Definition

A vitamin is an organic molecule (or a set of molecules closely related chemically, i.e. vitamers) that is an essential micronutrient which an organism needs in small quantities for the proper functioning of its metabolism.

Classification

Vitamins are classified as either water-soluble or fat-soluble. In humans there are 13 vitamins: 4 fat-soluble (A, D, E, and K) and 9 water-soluble (8 B vitamins and vitamin C). Water-soluble vitamins dissolve easily in water and, in general, are readily excreted from the body, to the degree that urinary output is a strong predictor of vitamin consumption.Because they are not as readily stored, more consistent intake is important.Fat-soluble vitamins are absorbed through the intestinal tract with the help of lipids (fats). Vitamins A and D can accumulate in the body, which can result in dangerous hypervitaminosis. Fat-soluble vitamin deficiency due to malabsorption is of particular significance in cystic fibrosis.

List of Vitamins

Vitamin A

Also known as retinol, has several important functions.These include:

• helping your body’s natural defence against illness and infection (the immune system) work properly
• helping vision in dim light
• keeping skin and the lining of some parts of the body, such as the nose, healthy

Good sources of vitamin A (retinol) include:

• cheese
• eggs
• oily fish
• fortified low-fat spreads
• milk and yoghurt
• liver and liver products such as liver pâté – this is a particularly rich source of vitamin A, so you may be at risk of having too much vitamin A if you have it more than once a week (if you’re pregnant you should avoid eating liver or liver products)

You can also get vitamin A by including good sources of  beta-carotene in your diet, as the body can convert this into retinol. 

The main food sources of beta-carotene are:

• yellow, red and green (leafy) vegetables, such as spinach, carrots, sweet potatoes and red peppers
• yellow fruit, such as mango, papaya and apricots

The total vitamin A content of a food is usually expressed as micrograms (µg) of retinol equivalents (RE).

The amount of vitamin A adults aged 19 to 64 need is:

• 700 µg a day for men
• 600 µg a day for women

You should be able to get all the vitamin A you need from your diet.Any vitamin A your body does not need immediately is stored for future use. This means you do not need it every day.Some research suggests that having more than an average of 1.5 mg (1,500 µg) a day of vitamin A over many years may affect your bones, making them more likely to fracture when you’re older.This is particularly important for older people, especially women, who are already at increased risk of osteoporosis, a condition that weakens bones.If you eat liver or liver pâté more than once a week, you may be getting too much vitamin A.Many multivitamins contain vitamin A. Other supplements, such as fish liver oil, are also high in vitamin A.If you take supplements containing vitamin A, make sure your daily intake from food and supplements does not exceed 1.5 mg (1,500 µg).If you eat liver every week, do not take supplements that contain vitamin A.

Having large amounts of vitamin A can harm your unborn baby. So if you’re pregnant or thinking about having a baby, do not eat liver or liver products, such as pâté, because these are very high in vitamin A.Also avoid taking supplements that contain vitamin A. Speak to your GP or midwife if you would like more information.

You should be able to get all the vitamin A you need by eating a varied and balanced diet.If you take a supplement that contains vitamin A, do not take too much because this could be harmful.Liver is a very rich source of vitamin A. Do not eat liver or liver products, such as pâté, more than once a week.You should also be aware of how much vitamin A there is in any supplements you take.If you’re pregnant or thinking of having a baby:

• avoid taking supplements containing vitamin A, including fish liver oil, unless advised to by your GP
• avoid liver or liver products, such as pâté, as these are very high in vitamin A

Women who have been through the menopause and older men, who are more at risk of osteoporosis, should avoid having more than 1.5mg of vitamin A a day from food and supplements.

This means:

• not eating liver or liver products, such as pâté, more than once a week, or having smaller portions of these
• taking no more than 1.5mg of vitamin A a day in supplements (including fish liver oil) if you do not eat liver or liver products
• not taking any supplements containing vitamin A (including fish liver oil) if you eat liver once a week

Having an average of 1.5mg a day or less of vitamin A from diet and supplements combined is unlikely to cause any harm.

Vitamin B

This section has information on:

• thiamin (vitamin B1)
• riboflavin (vitamin B2)
• niacin (vitamin B3)
• pantothenic acid
• vitamin B6
• biotin (vitamin B7)
• folate and folic acid
• vitamin B12

Thiamin (vitamin B1)

Thiamin, also known as vitamin B1, helps:

• the body break down and release energy from food
• keep the nervous system healthy

Thiamin is found in many types of food.

Good sources include:

• peas
• some fresh fruits (such as bananas and oranges)
• nuts
• wholegrain breads
• some fortified breakfast cereals
• liver

The amount of thiamin adults (aged 19 to 64) need is:

• 1mg a day for men
• 0.8mg a day for women

You should be able to get all the thiamin you need from your daily diet.Thiamin cannot be stored in the body, so you need it in your diet every day.There’s not enough evidence to know what the effects might be of taking high doses of thiamin supplements each day.

You should be able to get all the thiamin you need by eating a varied and balanced diet.If you take supplements, do not take too much as this might be harmful.Taking 100mg or less a day of thiamin supplements is unlikely to cause any harm.

Riboflavin (vitamin B2)

Riboflavin, also known as vitamin B2, helps:

• keep skin, eyes and the nervous system healthy
• the body release energy from food

Good sources of riboflavin include:

• milk
• eggs
• fortified breakfast cereals
• mushrooms
• plain yoghurt

UV light can destroy riboflavin, so ideally these foods should be kept out of direct sunlight.

The amount of riboflavin adults (aged 19 to 64) need is about:

• 1.3mg a day for men
• 1.1mg a day for women

You should be able to get all the riboflavin you need from your daily diet.Riboflavin cannot be stored in the body, so you need it in your diet every day.There’s not enough evidence to know what the effects might be of taking high doses of riboflavin supplements each day.You should be able to get all the riboflavin you need by eating a varied and balanced diet.

If you take supplements, do not take too much as this might be harmful.Taking 40mg or less a day of riboflavin supplements is unlikely to cause any harm.

Niacin (vitamin B3)

Niacin, also known as vitamin B3, helps:

• the body release energy from food
• keep the nervous system and skin healthy

There are 2 forms of niacin: nicotinic acid and nicotinamide. Both are found in food.

Good sources of niacin include:

• meat
• fish
• wheat flour
• eggs

The amount of niacin you need is about:

• 16.5mg a day for men
• 13.2mg a day for women

Pantothenic acid

Pantothenic acid has several functions, such as helping the body to release energy from food.

Pantothenic acid is found in varying amounts in almost all vegetables, wholegrain foods and meats, but good sources include:

• chicken
• beef
• liver and kidneys
• eggs
• mushrooms
• avocado

Breakfast cereals are also a good source if they have been fortified with pantothenic acid.

No amount has been set in the UK for how much pantothenic acid you need.You should be able to get all the pantothenic acid you need from your daily diet, as it’s found in many foods.Pantothenic acid cannot be stored in the body, so you need it in your diet every day.

There’s not enough evidence to know what the effects might be of taking high daily doses of pantothenic acid supplements.You should be able to get all the pantothenic acid you need by eating a varied and balanced diet.If you take supplements, do not take too much as this might be harmful.Taking 200mg or less a day of pantothenic acid in supplements is unlikely to cause any harm.

Vitamin B6

Vitamin B6, also known as pyridoxine, helps:

• the body to use and store energy from protein and carbohydrates in food
• the body form haemoglobin, the substance in red blood cells that carries oxygen around the body

Vitamin B6 is found in a wide variety of foods, including:

• pork
• poultry, such as chicken or turkey
• some fish
• peanuts
• soya beans
• wheatgerm
• oats
• bananas
• milk
• some fortified breakfast cereals

The amount of vitamin B6 adults (aged 19 to 64) need is about:

• 1.4mg a day for men
• 1.2mg a day for women

You should be able to get all the vitamin B6 you need from your daily diet.

The bacteria that live naturally in your bowel are also able to make vitamin B6.When taking a supplement, it’s important not to take too much.Taking 200mg or more a day of vitamin B6 [LK2] can lead to a loss of feeling in the arms and legs known as peripheral neuropathy. This will usually improve once you stop taking the supplements. But in a few cases when people have taken large amounts of vitamin B6, particularly for more than a few months, the effect can be permanent. The effect of taking vitamin B6 at doses between 10 and 200 mg is unclear. So there’s not enough evidence to say how long these doses could be taken for safely.

You should be able to get the vitamin B6 you need by eating a varied and balanced diet.If you take vitamin B6 supplements, do not take too much as this could be harmful.Do not take more than 10mg of vitamin B6 a day in supplements unless advised to by a doctor.

Biotin (vitamin B7)

Biotin is needed in very small amounts to help the body make fatty acids.

The bacteria that live naturally in your bowel are able to make biotin, so it’s not clear if you need any additional biotin from the diet.Biotin is also found in a wide range of foods, but only at very low levels.There’s not enough evidence to know what the effects might be of taking high daily doses of biotin supplements.

You should be able to get all the biotin you need by eating a varied and balanced diet.If you take biotin supplements, do not take too much as this might be harmful.Taking 0.9mg or less a day of biotin in supplements is unlikely to cause any harm.

Folate and folic acid

Folate is a B vitamin found in many foods. The manmade form of folate is called folic acid.

Folate is also known as folacin and vitamin B9.

Folate helps:

• the body form healthy red blood cells
• reduce the risk of birth defects called neural tube defects, such as spina bifida, in unborn babies

A lack of folate could lead to folate deficiency anaemia.

Folate is found in small amounts in many foods.

Good sources include:

• broccoli
• brussels sprouts
• leafy green vegetables, such as cabbage, kale, spring greens and spinach
• peas
• chickpeas and kidney beans
• liver (but avoid this during pregnancy)
• breakfast cereals fortified with folic acid

Adults need 200 micrograms of folate a day. A microgram is 1,000 times smaller than a milligram (mg). The word microgram is sometimes written with the Greek symbol μ followed by the letter g (μg).

There are no long-term stores in the body, so you need to eat folate-containing foods frequently.Most people should be able to get the amount of folate they need by eating a varied and balanced diet.If you’re pregnant, trying for a baby, or could get pregnant, it’s recommended that you take a 400 microgram folic acid supplement daily until you’re 12 weeks pregnant.Folic acid supplements need to be taken before you get pregnant, so start taking them before you stop using contraception or if there’s a chance you might get pregnant.This is to help prevent neural tube defects, such as spina bifida, in your baby.

Some women have an increased risk of having a pregnancy affected by a neural tube defect and are advised to take a higher dose of 5mg of folic acid each day until they’re 12 weeks pregnant.This is important and unlikely to cause harm, as it’s taken on a short-term basis, but speak to your doctor first.Get more advice about vitamins and minerals during pregnancy, including who should take a higher dose of folic acid.

Taking doses of folic acid higher than 1mg can mask the symptoms of vitamin B12 deficiency, which can eventually damage the nervous system if it’s not spotted and treated.This is particularly a concern for older people because it becomes more difficult to absorb vitamin B12 as you get older.The Department of Health and Social Care recommends that folic acid supplements are taken by all women who are pregnant or could get pregnant.Women who cannot get pregnant and men should be able to get all the folate they need by eating a varied and balanced diet.If you’re taking folic acid supplements, it’s important not to take too much as this could be harmful.Taking 1mg or less a day of folic acid supplements is unlikely to cause any harm.

Vitamin B12

Vitamin B12 is involved in helping the body:

• make red blood cells and keeping the nervous system healthy
• release energy from food
• use folate

A lack of vitamin B12 could lead to vitamin B12 deficiency anaemia.

Good sources include:

• meat
• fish
• milk
• cheese
• eggs
• some fortified breakfast cereals

Adults (aged 19 to 64) need about 1.5 micrograms a day of vitamin B12.If you eat meat, fish or dairy foods, you should be able to get enough vitamin B12 from your diet.But as vitamin B12 is not found naturally in foods such as fruit, vegetables and grains, vegans may not get enough of it.Read about the vegan diet for nutrition information and advice.There’s not enough evidence to show what the effects may be of taking high doses of vitamin B12 supplements each day.

You should be able to get all the vitamin B12 you need by eating a varied and balanced diet.If you take vitamin B12 supplements, do not take too much as this could be harmful.Taking 2mg or less a day of vitamin B12 in supplements is unlikely to cause any harm.

Vitamin C

Also known as ascorbic acid, has several important functions.

These include:

• helping to protect cells and keeping them healthy
• maintaining healthy skin, blood vessels, bones and cartilage
• helping with wound healing

Lack of vitamin C can lead to scurvy.Vitamin C is found in a wide variety of fruit and vegetables.

Good sources include:

• citrus fruit, such as oranges and orange juice
• peppers
• strawberries
• blackcurrants
• broccoli
• brussels sprouts
• potatoes

Adults aged 19 to 64 need 40mg of vitamin C a day.You should be able to get all the vitamin C you need from your daily diet.Vitamin C cannot be stored in the body, so you need it in your diet every day.Taking large amounts (more than 1,000mg per day) of vitamin C can cause:

• stomach pain
• diarrhoea
• flatulence

These symptoms should disappear once you stop taking vitamin C supplements.You should be able to get all the vitamin C you need by eating a varied and balanced diet.If you take vitamin C supplements, do not take too much as this could be harmful.Taking less than 1,000mg of vitamin C supplements a day is unlikely to cause any harm.

Vitamin D

It helps regulate the amount of calcium and phosphate in the body.These nutrients are needed to keep bones, teeth and muscles healthy.A lack of vitamin D can lead to bone deformities such as rickets in children, and bone pain caused by a condition called osteomalacia in adults.From about late March/early April to the end of September, most people should be able to make all the vitamin D they need from sunlight.The body creates vitamin D from direct sunlight on the skin when outdoors.But between October and early March we do not make enough vitamin D from sunlight. Read more about vitamin D and sunlight.

Vitamin D is also found in a small number of foods.

Sources include:

• oily fish – such as salmon, sardines, herring and mackerel
• red meat
• liver
• egg yolks
• fortified foods – such as some fat spreads and breakfast cereals

Another source of vitamin D is dietary supplements.

In the UK, cows’ milk is generally not a good source of vitamin D because it is not fortified, as it is in some other countries.

From about late March/early April to the end of September, the majority of people should be able to make all the vitamin D they need from sunlight on their skin.Children from the age of 1 year and adults need 10 micrograms of vitamin D a day. This includes pregnant and breastfeeding women, and people at risk of vitamin D deficiency.

Babies up to the age of 1 year need 8.5 to 10 micrograms of vitamin D a day.A microgram is 1,000 times smaller than a milligram (mg). The word microgram is sometimes written with the Greek symbol μ followed by the letter g (μg).Sometimes the amount of vitamin D is expressed as International Units (IU). 1 microgram of vitamin D is equal to 40 IU. So 10 micrograms of vitamin D is equal to 400 IU.

During the autumn and winter, you need to get vitamin D from your diet because the sun is not strong enough for the body to make vitamin D.But since it’s difficult for people to get enough vitamin D from food alone, everyone (including pregnant and breastfeeding women) should consider taking a daily supplement containing 10 micrograms of vitamin D during the autumn and winter.Between late March/early April to the end of September, most people can make all the vitamin D they need through sunlight on their skin and from a balanced diet.You may choose not to take a vitamin D supplement during these months.Some people will not make enough vitamin D from sunlight because they have very little or no sunshine exposure.The Department of Health and Social Care recommends that adults and children over 4 take a daily supplement containing 10 micrograms of vitamin D throughout the year if they:

• are not often outdoors – for example, if they’re frail or housebound
• are in an institution like a care home
• usually wear clothes that cover up most of their skin when outdoors

If you have dark skin – for example you have an African, African-Caribbean or south Asian background – you may also not make enough vitamin D from sunlight.You should consider taking a daily supplement containing 10 micrograms of vitamin D throughout the year.The Department of Health and Social Care recommends that babies from birth to 1 year of age should have a daily supplement containing 8.5 to 10 micrograms of vitamin D throughout the year if they are:

• breastfed
• formula-fed and are having less than 500ml (about a pint) of infant formula a day, as infant formula is already fortified with vitamin D

Children aged 1 to 4 years old should be given a daily supplement containing 10 micrograms of vitamin D throughout the year.You can buy vitamin D supplements or vitamin drops containing vitamin D (for under 5s) at most pharmacies and supermarkets.Women and children who qualify for the Healthy Start scheme can get free supplements containing vitamin D.

Taking too many vitamin D supplements over a long period of time can cause too much calcium to build up in the body (hypercalcaemia). This can weaken the bones and damage the kidneys and the heart.If you choose to take vitamin D supplements, 10 micrograms a day will be enough for most people.

Do not take more than 100 micrograms (4,000 IU) of vitamin D a day as it could be harmful. This applies to adults, including pregnant and breastfeeding women and the elderly, and children aged 11 to 17 years.Children aged 1 to 10 years should not have more than 50 micrograms (2,000 IU) a day. Infants under 12 months should not have more than 25 micrograms (1,000 IU) a day.Some people have medical conditions that mean they may not be able to safely take as much. If in doubt, you should consult your doctor.If your doctor has recommended you take a different amount of vitamin D, you should follow their advice.

You cannot overdose on vitamin D through exposure to sunlight. But always remember to cover up or protect your skin if you’re out in the sun for long periods to reduce the risk of skin damage and skin cancer.

Vitamin E

It helps maintain healthy skin and eyes, and strengthen the body’s natural defence against illness and infection (the immune system).

Vitamin E is a group of compounds found in a wide variety of foods.

Good sources include:

• plant oils – such as rapeseed (vegetable oil), sunflower, soya, corn and olive oil
• nuts and seeds
• wheatgerm – found in cereals and cereal product

The amount of vitamin E you need is:

• 4mg a day for men
• 3mg a day for women

You should be able to get all the vitamin E you need from your diet.

Any vitamin E your body does not need immediately is stored for future use, so you do not need it in your diet every day.There is not enough evidence to know what the effects might be of taking high doses of vitamin E supplements each day.

You should be able to get the amount of vitamin E you need by eating a varied and balanced diet.If you take vitamin E supplements, do not take too much as this could be harmful.Taking 540mg (800 IU) or less a day of vitamin E supplements is unlikely to cause any harm.

Vitamin K

It is a group of vitamins that the body needs for blood clotting, helping wounds to heal.

There’s also some evidence vitamin K may help keep bones healthy.

Vitamin K is found in:

• green leafy vegetables – such as broccoli and spinach
• vegetable oils
• cereal grains

Small amounts can also be found in meat and dairy foods.Adults need approximately 1 microgram a day of vitamin K for each kilogram of their body weight.For example, someone who weighs 65kg would need 65 micrograms a day of vitamin K, while a person who weighs 75kg would need 75 micrograms a day.A microgram is 1,000 times smaller than a milligram (mg). The word microgram is sometimes written with the Greek symbol μ followed by the letter g (μg).You should be able to get all the vitamin K you need by eating a varied and balanced diet.Any vitamin K your body does not need immediately is stored in the liver for future use, so you do not need it in your diet every day.

There’s not enough evidence to know what the effects might be of taking high doses of vitamin K supplements each day.You should be able to get all the vitamin K you need by eating a varied and balanced diet.If you take vitamin K supplements, do not take too much as this might be harmful.Taking 1mg or less of vitamin K supplements a day is unlikely to cause any harm.

DEFICIENCY OF VITAMINS

1. Vitamin A: (Retinol)

The important deficiency states due to lack of vitamin A in the diet are:

1.     Night Blindness: In the early stages of vitamin A deficiency,the individual cannot see well in dim light. In advanced deficiency, the subject cannot see objects in dim light.

2.     Xerosis Conjunctiva: The conjunctiva is dry, thickened,wrinkled and pigmented. The pigmentation gives conjunctiva a smoky appearance.

3.     Xerosis Cornea: When dryness spreads to cornea, it takeson a hazy, lusterless appearance.

4.     Bitot’s Spots: Greyish glistening white plaques, formed of desquamated thickened conjuctival epithelium, usually triangular in shape and firmly adhering to the conjuctiva.

5.     Keratomalacia : When xerosis of the conjuctiva and cornea is not treated, it may develop into a condition known as keratomalacia.

6.     Follicullar Hyperkeratosis: The skin becomes rough and dry.

Under the national prophylaxis programme against nutritional blindness 2,00,000 IU of vitamin A in oil is administered every six months to preschool children to eliminate vitamin A deficiency.

2. Vitamin D (7 – dehydro cholestrol)

i. Rickets

The chief signs in fully developed active rickets are found in the chest wall (beading), waists and ankles (thickening) and various deformities (knock – knees and bow legs). The child is restless, fretful and pale with flabby and toneless muscles, which allow the limbs to assume unnatural postures. Development is delayed so that the teeth often erupt late and there is failure to sit up, stand, crawl and walk at the normal ages. There is usually a protuberant abdomen so called potbelly.

ii. OsteomalaciaIt may be called as adult rickets. It occurs generally in pregnant women. The changes in bone are similar to rickets. Skeletal pain is usually present and persistent and ranges from a dull ache to severe pain. Muscular weakness is often present and the patient may find difficulty in climbing stairs or getting out of a chair.

3. Vitamin E (Tocopherol)

Vitamin E deficiency in animals causes several disorders such as reproduction failure, liver necrosis, etc,

4. Vitamin K

Vitamin K deficiency leads to haemorrhagic conditions.

5. Vitamin C (Ascorbic Acid)

Severe Vitamin C deficiency results in the development of the disease scurvy. The disease is characterized by

General weakness followed by shortness of breath, pain in bones, joints and muscles of the extremities.

Swollen and tender joints, haemorrhages in various tissues and pain in joints.

Bleeding gums and loose teeth.

In infantile scurvy, the infant screams if picked up or moved or handled. There is pain and tenderness of the limbs.

6. Vitamin B₁ (Thiamine)

Thiamine deficiency causes the disease, beriberi, in human beings. Two forms of beriberi namely wet beriberi and dry beriberi occurs in adults. The first symptoms are anorexia (loss of appetite) with heaviness and weakness of the legs. There is pain and numbness in the legs. The subjects feel weak and get easily exhausted. Oedema is the important feature of wet beriberi. The calf muscles are swollen. The pulse is fast and bouncing. The heart becomes weak and death occurs due to heart failure. In infantile beriberi, the first symptoms are restlessness, sleeplessness and cardiac failure.

7. Vitamin B₂ or Riboflavin

Riboflavin deficiency is characterized by

a)Angular stomatitis:

The lesions at the angles of the mouth are termed as angular stomatitis.

b) Glossitis

The tongue in general is acutely inflamed called as glossitis.

c) Skin lesions occur on the nasolabial folds and on the ears as shown in the picture below.

Cheilosis which is the dry chapped appearance of the lips.

Behavioural abnormalities occur in riboflavin deficient children.

8. Vitamin B₃ (Niacin)

Niacin deficiency causes the disease pellagra in humans. Pellagra is also called Disease of 3D’s. Because the disease has the symptoms of diarrhoea, dermatitis and depression. The disease is characterized by the following.

Glossitis and diarrhoea – These are the two outstandingsymptoms. Nausea and vomiting are seen in most cases.

The dermatitis is the most characteristic symptom of the disease. The commonest sites are the back of the fingers and hands, the forearms, and the neck. The following pictures show dermatitis on hands and neck.

c) Milder mental disturbances consisting of irritability, depression, inability to concentrate and poor memory are common in niacin deficiency.

9. Vitamin B₆ or Pyridoxine

 Pyridoxine deficiency results in the following

Hypochromic microcytic anaemia.

Sleep disturbances, irritability and depression

Angular stomatitis, glossitis and cheilosis in pregnant and lactating mothers.

10. Pantothenic Acid

The visible signs of deficiency include nausea, vomiting, tremor of the outstretched hands, irritability and burning feet syndrome.

11. Folic Acid

Folic acid deficiency causes megaloblastic anaemia mainly in pregnant women of low income groups.

12. Vitamin B₁₂

Vitamin B₁₂ deficiency causes perinicious anemia in humans. Soreness and inflammation of the tongue are commonly observed. Parasthesia (numbness and tingling) occurs in fingers and toes. Persons living exclusively on vegetarian diets develop vitamin B₁₂ deficiency.

Antivitamins

Anti-vitamins are chemical compounds that inhibit the absorption or actions of vitamins. For example, avidin is a protein in raw egg whites that inhibits the absorption of biotin; it is deactivated by cooking.Pyrithiamine, a synthetic compound, has a molecular structure similar to thiamine, vitamin B₁, and inhibits the enzymes that use thiamine.

Effects of cooking

Research in Vitamins

The Nobel Prize in Physiology or Medicine for 1929 was awarded to Christiaan Eijkman and Sir Frederick Gowland Hopkins for their contributions to the discovery of vitamins.Thirty-five years earlier, Eijkman had observed that chickens fed polished white rice developed neurological symptoms similar to those observed in military sailors and soldiers fed a rice-based diet, and that the symptoms were reversed when the chickens were switched to whole-grain rice. He called this “the anti-beriberi factor”, which was later identified as vitamin B₁, thiamine.

In 1930, Paul Karrer elucidated the correct structure for beta-carotene, the main precursor of vitamin A, and identified other carotenoids. Karrer and Norman Haworth confirmed Albert Szent-Györgyi’s discovery of ascorbic acid and made significant contributions to the chemistry of flavins, which led to the identification of lactoflavin. For their investigations on carotenoids, flavins and vitamins A and B₂, they both received the Nobel Prize in Chemistry in 1937.

In 1931, Albert Szent-Györgyi and a fellow researcher Joseph Svirbely suspected that “hexuronic acid” was actually vitamin C, and gave a sample to Charles Glen King, who proved its anti-scorbutic activity in his long-established guinea pig scorbutic assay. In 1937, Szent-Györgyi was awarded the Nobel Prize in Physiology or Medicine for his discovery. In 1943, Edward Adelbert Doisy and Henrik Dam were awarded the Nobel Prize in Physiology or Medicine for their discovery of vitamin K and its chemical structure. In 1967, George Wald was awarded the Nobel Prize (along with Ragnar Granit and Haldan Keffer Hartline) for his discovery that vitamin A could participate directly in a physiological process.In 1938, Richard Kuhn was awarded the Nobel Prize in Chemistry for his work on carotenoids and vitamins, specifically B₂ and B₆.Five people have been awarded Nobel Prizes for direct and indirect studies of vitamin B₁₂: George Whipple, George Minot and William P. Murphy (1934), Alexander R. Todd (1957), and Dorothy Hodgkin (1964).

Hormones

A hormone (from the Greek participle ὁρμῶν, “setting in motion”) is any member of a class of signaling molecules in multicellular organisms, that are transported to distant organs to regulate physiology and behavior.^[1] Hormones are required for the correct development of animals, plants and fungi. The lax definition of a hormone (as a signalling molecule that acts distant from its site of production) means that many different classes of molecule can be defined as hormones. Among the substances that can be considered hormones, are eicosanoids (e.g. prostaglandins and thromboxanes), steroids (e.g. oestrogen and brassinosteroid), amino acid derivatives (e.g. epinephrine and auxin), protein / peptides (e.g. insulin and CLE peptides) and gases (e.g ethylene and nitrous oxide).

Hormone disorders are diagnosed in the laboratory as well as by clinical appearance and features. Laboratory tests can be used to test bodily fluids such as the blood, urine or saliva for hormone abnormalities.

In the case of hormone deficiency, a synthetic hormone replacement therapy may be used and in cases of excess hormone production, medications may be used to curb the effects of the hormone. For example, a person with an underactive thyroid gland or hypothyroidism may be treated with synthetic thyroxine which can be taken in the form of a pill, while a person with an overactive thyroid may be administered a drug such as propranolol to counteract the effects of the excess thyroid hormone.

Hormonal regulation is closely related to that exerted by the nervous system, and the two processes have generally been distinguished by the rate at which each causes effects, the duration of these effects, and their extent; i.e., the effects of endocrine regulation may be slow to develop but prolonged in influence and widely distributed through the body, whereas nervous regulation is typically concerned with quick responses that are of brief duration and localized in their effects. Advances in knowledge, however, have modified these distinctions.Nerve cells are secretory, for responses to the nerve impulses that they propagate depend upon the production of chemical transmitter substances, or neurotransmitters, such as acetylcholine and norepinephrine (noradrenaline), which are liberated at nerve endings in minute amounts and have only a momentary action. It has been established, however, that certain specialized nerve cells, called neurosecretory cells, can translate neural signals into chemical stimuli by producing secretions called neurohormones. These secretions, which are often polypeptides (compounds similar to proteins but composed of fewer amino acids), pass along nerve-cell extensions, or axons, and are typically released into the bloodstream at special regions called neurohemal organs, where the axon endings are in close contact with blood capillaries. Once released in this way, neurohormones function in principle similar to hormones that are transmitted in the bloodstream and are synthesized in the endocrine glands.The distinctions between neural and endocrine regulation, no longer as clear-cut as they once seemed to be, are further weakened by the fact that neurosecretory nerve endings are sometimes so close to their target cells that vascular transmission is not necessary. There is good evidence that hormonal regulation occurs by diffusion in plants and (although here the evidence is largely indirect) in lower animals (e.g., coelenterates), which lack a vascular system.

Hormones have a long evolutionary history, knowledge of which is important if their properties and functions are to be understood. Many important features of the vertebrate endocrine system, for example, are present in the lampreys and hagfishes, modern representatives of the primitively jawless vertebrates (Agnatha), and these features were presumably present in fossil ancestors that lived more than 500 million years ago. The evolution of the endocrine system in the more advanced vertebrates with jaws (Gnathostomata) has involved both the appearance of new hormones and the further evolution of some of those already present in agnathans; in addition, extensive specialization of target organs has occurred to permit new patterns of response.

The factors involved in the first appearance of the various hormones is largely a matter for conjecture, although hormones clearly are only one mechanism for chemical regulation, diverse forms of which are found in living things at all stages of development. Other mechanisms for chemical regulation include chemical substances (so-called organizer substances) that regulate early embryonic development and the pheromones that are released by social insects as sex attractants and regulators of the social organization. Perhaps, in some instances, chemical regulators including hormones appeared first as metabolic by-products. A few such substances are known in physiological regulation: carbon dioxide, for example, is involved in the regulation of the respiratory activity of which it is a product, in insects as well as in vertebrates. Substances such as carbon dioxide are called parahormones to distinguish them from true hormones, which are specialized secretions.

Hormones are used to communicate between organs and tissues. In vertebrates, hormones are responsible for the regulation of many physiological processes and behavioral activities such as digestion, metabolism, respiration, sensory perception, sleep, excretion, lactation, stress induction, growth and development, movement, reproduction, and mood manipulation.^[2][3] In plants, hormones modulate almost all aspects of development, from germination to senescence.^[4]

Hormones affect distant cells by binding to specific receptor proteins in the target cell, resulting in a change in cell function. When a hormone binds to the receptor, it results in the activation of a signal transduction pathway that typically activates gene transcription, resulting in increased expression of target proteins. Hormones can also act in rapid, non-genomic pathways that can be synergistic with genomic effects.^[5] Water-soluble hormones (such as peptides and amines) generally act on the surface of target cells via second messengers. Lipid soluble hormones, (such as steroids) generally pass through the plasma membranes of target cells (both cytoplasmic and nuclear) to act within their nuclei. A notable exception to this are brassinosteroids in plants, which despite being lipid soluble, still bind to their receptor at the cell surface.^[6]

In vertebrates, endocrine glands are specialized organs that secrete hormones into the endocrine signaling system. Hormone secretion occurs in response to specific biochemical signals and is often subject to negative feedback regulation. For instance, high blood sugar (serum glucose concentration) promotes insulin synthesis. Insulin then acts to reduce glucose levels and maintain homeostasis, leading to reduced insulin levels. Upon secretion water soluble hormones are readily transported through the circulatory system. Lipid-soluble hormones must bond to carrier plasma glycoproteins (e.g., thyroxine-binding globulin (TBG)) to form ligand-protein complexes. Some hormones are completely active^[which?] when released into the bloodstream (as is the case for insulin and growth hormones), while others are prohormones that must be activated in specific cells through a series of activation steps that are commonly highly regulated. The endocrine system secretes hormones directly into the bloodstream, typically via fenestrated capillaries, whereas the exocrine system secretes its hormones indirectly using ducts. Hormones with paracrine function diffuse through the interstitial spaces to nearby target tissue.

Plants lack specialized organs for the secretion of hormones, although there is spacial distribution of hormone production. For example, the hormone auxin is produced mainly at the tips of young leaves and in the shoot apical meristem. The lack of specialised glands means that the main site of hormone production can change throughout the life of a plant, and the site of production is dependent on the plant’s age and environment.^[7]

Hormonal signaling involves the following steps:^[8]

1. Biosynthesis of a particular hormone in a particular tissue
2. Storage and secretion of the hormone
3. Transport of the hormone to the target cell(s)
4. Recognition of the hormone by an associated cell membrane or intracellular receptor protein
5. Relay and amplification of the received hormonal signal via a signal transduction process: This then leads to a cellular response. The reaction of the target cells may then be recognized by the original hormone-producing cells, leading to a downregulation in hormone production. This is an example of a homeostatic negative feedback loop.
6. Breakdown of the hormone.

Hormone producing cells are typically of a specialized cell type, residing within a particular endocrine gland, such as the thyroid gland, ovaries, and testes. Hormones exit their cell of origin via exocytosis or another means of membrane transport. The hierarchical model is an oversimplification of the hormonal signaling process. Cellular recipients of a particular hormonal signal may be one of several cell types that reside within a number of different tissues, as is the case for insulin, which triggers a diverse range of systemic physiological effects. Different tissue types may also respond differently to the same hormonal signal.

Arnold Adolph Berthold was a German physiologist and zoologist, who, in 1849, had a question about the function of the testes. He noticed that in castrated roosters that they did not have the same sexual behaviors as roosters with their testes intact. He decided to run an experiment on male roosters to examine this phenomenon. He kept a group of roosters with their testes intact, and saw that they had normal sized wattles and combs (secondary sexual organs), a normal crow, and normal sexual and aggressive behaviors. He also had a group with their testes surgically removed, and noticed that their secondary sexual organs were decreased in size, had a weak crow, did not have sexual attraction towards females, and were not aggressive. He realized that this organ was essential for these behaviors, but he did not know how. To test this further, he removed one testis and placed it in the abdominal cavity. The roosters acted and had normal physical anatomy. He was able to see that location of the testes do not matter. He then wanted to see if it was a genetic factor that was involved in the testes that provided these functions. He transplanted a testis from another rooster to a rooster with one testis removed, and saw that they had normal behavior and physical anatomy as well. Berthold determined that the location or genetic factors of the testes do not matter in relation to sexual organs and behaviors, but that some chemical in the testes being secreted is causing this phenomenon. It was later identified that this factor was the hormone testosterone.^[9][10]

Charles and Francis Darwin (1880)[edit]

Although known primarily for his work on the Theory of Evolution, Charles Darwin was also keenly interested in plants. Through the 1870s, he and his son Francis studied the movement of plants towards light. They were able to show that light is perceived at the tip of a young stem (the coleoptile), whereas the bending occurs lower down the stem. They proposed that a ‘transmissible substance’ communicated the direction of light from the tip down to the stem. The idea of a ‘transmissible substance’ was initially dismissed by other plant biologists, but their work later led to the discovery of the first plant hormone.^[11] In the 1920s Dutch scientist Frits Warmolt Went and Russian scientist Nikolai Cholodny (working independently of each other) conclusively showed that asymmetric accumulation of a growth hormone was responsible for this bending. In 1933 this hormone was finally isolated by Kögl, Haagen-Smit and Erxleben and christened ‘auxin‘.^[11][12][13]

Bayliss and Starling (1902)[edit]

William Bayliss and Ernest Starling, a physiologist and biologist, respectively, wanted to see if the nervous system had an impact on the digestive system. They knew that the pancreas was involved in the secretion of digestive fluids after the passage of food from the stomach to the intestines, which they believed to be due to the nervous system. They cut the nerves to the pancreas in an animal model and discovered that it was not nerve impulses that controlled secretion from the pancreas. It was determined that a factor secreted from the intestines into the bloodstream was stimulating the pancreas to secrete digestive fluids. This factor was named secretin: a hormone, although the term hormone was not coined until 1905 by Starling.^[14]

Endocrine system

Endocrine glands make chemicals called hormones and pass them straight into the bloodstream. Hormones can be thought of as chemical messages.

From the blood stream, the hormones communicate with the body by heading towards their target cell to bring about a particular change or effect to that cell. The hormone can also create changes in the cells of surrounding tissues (paracrine effect). The endocrine system works with the nervous system and the immune system to help the body cope with different events and stresses.

This branch of medicine – relating to the study of the endocrine system – is called endocrinology and is practiced by endocrinologists. The field is rapidly expanding due to understanding of the cellular pathways that hormones stimulate and the discovery of new hormones and their actions.

Exocrine glands

An exocrine gland, unlike an endocrine gland, is a gland that secretes substances (electrolytes, proteins or enzymes) straight to a target site via ducts or tube. Some examples include:

• Salivary glands
• Sweat glands
• Sebaceous glands
• The pancreas.

The pancreas is both an endocrine and exocrine organ. It releases certain enzymes to aid in digestion delivered to the gut via the pancreatic duct. The endocrine pancreas also releases hormones such as insulin and glucagon, which are hormones predominantly related to glucose metabolism, into the blood stream.

Functions of the endocrine system

Some of the roles of the endocrine system include:

• Growth
• Repair
• Sexual reproduction
• Digestion
• Homeostasis (constant internal balance).

How hormones work

A hormone will only act on a part of the body if it ‘fits’. A hormone can be thought of as a key, and its target site (such as an organ) has specially shaped locks on the cell walls. If the hormone fits the cell wall, then it will work.

The hormones can set off a cascade of other signaling pathways in the cell to cause an immediate effect (for instance, insulin signaling leads to a rapid uptake of glucose into muscle cells) or a more delayed effect (glucocorticoids bind to DNA elements in a cell to switch on the production of certain proteins, which takes a while to produce).

The endocrine system is a tightly regulated system that keeps the hormones and their effects at just the right level. One way this is achieved is through ‘feedback loops’. The release of hormones is regulated by other hormones, proteins or neuronal signals.

The released hormone then has its effect on other organs. This effect on the organ feeds back to the original signal to control any further hormone release. The pituitary gland is well known for its feedback loops.

Endocrine glands and organs

The main glands and organs of the endocrine system include:

• Pituitary gland – is inside the brain. It oversees the other glands and keeps hormone levels in check. It can bring about a change in hormone production somewhere else in the system by releasing its own ‘stimulating’ hormones. The pituitary gland is also connected to the nervous system through part of the brain called the hypothalamus. The hormones released by the pituitary gland are gonadotropins (LH and FSH), growth hormone (GH), thyroid stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), prolactin, antidiuretic hormone and oxytocin.
• Thyroid gland – sits in the neck at the front of the windpipe. It releases thyroid hormone (T4 and T3) which is required for metabolism and body homeostasis. It is controlled by TSH which is produced by the pituitary gland through a feed-back loop.
• Parathyroid gland – there are usually four parathyroid glands which lie alongside the thyroid gland. The parathyroid gland is involved in calcium, phosphate and vitamin D regulation.
• Adrenal glands – there are two adrenal glands which sit on top of each kidney. They make a number of different hormones. The outside part of the gland (adrenal cortex) makes cortisol, aldosterone and sex hormones. The centre of the adrenal gland (adrenal medulla) makes adrenaline. Adrenaline is an example of a hormone that is under the control of the nervous system.
• Pancreas – an organ of digestion which is inside the abdomen. It makes insulin, which controls the amount of sugar in the bloodstream. It also makes other hormones such as glucagon and somatostatin.
• Ovaries – are inside the female pelvis. They make female sex hormones like oestrogen.
• Testes – they hang in the male scrotal sack. They make male sex hormones like testosterone.

Other lesser known endocrine organs include:

• Adipose tissue (fat tissue) – is recognised to be metabolically important. It releases hormones such as leptin, which affect appetite, and is also a site of oestrogen production. Insulin also acts on adipose tissue.
• Kidneys – produce erythropoietin (EPO) which stimulates red blood cell production, produce renin which is needed for blood pressure regulation and produce the active form of Vitamin D (1–25 dihydroxy vitamin D3)
• Gut – an increasing number of hormones in the gut are being researched and being understood to effect metabolism and appetite. Included are glucagon-like peptide 1 (GLP–1), ghrelin which stimulates appetite, and somatostatin.

Numerous problems can occur in the endocrine system. These can be considered as excessive or deficient hormone production. Endocrine organs are also prone to tumours (adenomas) which can over produce hormones. Some problems of the endocrine system include:

• Diabetes – too much sugar in the blood caused by problems with insulin production. This includes type 1 diabetes (deficiency of insulin) and type 2 diabetes (initially excessive, then deficiency, of insulin).
• Menstruation abnormalities – irregular menstruation or lack of menstruation. Some causes of this include polycystic ovarian syndrome (PCOS), pituitary adenoma or primary ovarian failure (POF).
• Thyroid problems – when the gland is overactive (hyperthyroidism) or underactive (hypothyroidism). Thyroid nodules are common but thyroid cancers are rare.
• Parathyroid problems – an enlargement or one of more of the parathyroid glands can lead to high calcium levels in the blood (hypercalcemia).
• Pituitary adenomas – these are tumours of the pituitary gland that can make too much of a certain hormone or cause deficiencies of hormones. These tumours can be small (microadenomas) or large (macroadenomas).
• Neuro-endocrine tumours – these are rare to tumours of certain endocrine glands (usually the adrenal gland, pancreas or small bowel). These can include too much adrenaline released by the adrenal gland (pheochromocytoma), or too much hormone 5–HIAA from a carcinoid tumour which causes diarrhoea and flushing.

Stress and Hormones

In the modern environment one is exposed to various stressful conditions. Stress can lead to changes in the serum level of many hormones including glucocorticoids, catecholamines, growth hormone and prolactin. Some of these changes are necessary for the fight or flight response to protect oneself. Some of these stressful responses can lead to endocrine disorders like Graves’ disease, gonadal dysfunction, psychosexual dwarfism and obesity. Stress can also alter the clinical status of many preexisting endocrine disorders such as precipitation of adrenal crisis and thyroid storm.‘Stress’ may be defined as any situation which tends to disturb the equilibrium between a living organism and its environment. In day-to-day life there are many stressful situations such as stress of work pressure, examinations, psychosocial stress and physical stresses due to trauma, surgery and various medical disorders. In this review, we will highlight in brief the hormonal changes in stress and its impact on the endocrine system with particular emphasis on Graves’ disease.

In response to stress, the level of various hormones changes. Reactions to stress are associated with enhanced secretion of a number of hormones including glucocorticoids, catecholamines, growth hormone and prolactin, the effect of which is to increase mobilization of energy sources and adapt the individual to its new circumstance.Activation of the pituitary-adrenal axis is a prominent neuroendocrine response to stress, promoting survival. Stimulation of this axis results in hypothalamic secretion of corticotrophin-releasing factor (CRF). CRF then stimulates the pituitary to adrenocorticotropin (ACTH), 8-lipotropin and 3-endorphin. Plasma levels of these hormones can increase two- to fivefold during stress in humans. The paraventricular nucleus of the hypothalamus is responsible for the integrated response to stress. Norepinephrine, serotonin and acetylcholine mediate much of the neurogenic stimulation of CRF production.

Stimulation of the pituitary-adrenal axis is associated with release of catecholamines. This leads to increased cardiac output, skeletal muscle blood flow, sodium retention, reduced intestinal motility, cutaneous vasoconstriction, increased glucose, bronchiolar dilatation and behavioral activation. Timio et al., have reported increased activation of the adrenosympathetic system during occupational stress.Acute stress leads to rapid release of vasopressin from the paraventricular nucleus of the hypothalamus along with corticotrophin releasing hormone CRH. Vasopressin can stimulate secretion of ACTH from the pituitary by acting on the V1b receptor, potentiating the effect of CRH. During chronic stress with corticotroph responsiveness there is preferential expression of hypothalamic vasopressin over CRH.

In stress there is suppression of circulating gonadotropins and gonadal steroid hormones leading to disruption of the normal menstrual cycle.Prolonged exposure to stress can lead to complete impairment of reproductive function.Gonadotrophin releasing hormone GnRH drive to the pituitary is decreased, probably due to increased endogenous CRH secretion.

Thyroid function is usually down-regulated during stressful conditions. T3 and T4 levels decrease with stress. Stress inhibits the thyroid-stimulating hormone (TSH) secretion through the action of glucocorticoids on the central nervous system.

The relationship between stressful life events and the onset of Graves′ disease (GD) was initially documented by Parry in 1825. There is data available on the high incidence of thyrotoxicosis among refugees from Nazi prison camps. Psychological distress has been reported in up to 65% of younger patients with hyperthyroidism and physical stress in many older patients.The term ′Kriegsbasedow′ was coined following the observation of increased incidence of GD during major wars. Many epidemiological studies have demonstrated that patients with GD had more stressful life events than control subjects prior to the onset or diagnosis of Graves′ hyperthyroidism and that stress had an unfavorable effect on the prognosis of GD. A study by Winsa et al., has indicated that negative life events may be a risk factor for GD. Compared with controls, newly diagnosed Graves′ patients claimed to have had more negative life events in the 12 months preceding the diagnosis, and negative life-event scores were also significantly higher (odds ratio 6.3, 95% confidence interval 2.7-14.7, for the category with the highest negative score).Sonino et al., in Italy examined 70 patients with GD and a control group of 70 healthy subjects and reported that patients with GD had significantly more positive and negative life events than controls (patients 1.51 total events, controls 0.54; P< 0.001). They investigated the occurrence of stressful life events in the year before the first sign of disease onset.Kung et al., from Hong Kong and Radosavljevi΄c et al., from Yugoslavia also reported association of negative life events with GD. In the study by Yoshiuchi et al., a positive correlation between stress and GD was found in female patients, but not in male patients. Patients with GD not only had a significantly greater number of stressful life events but also a higher number and greater impact of negative stressful life events compared to patients with toxic nodules and normal controls.Paunkovic et al., reported a significant increase in the incidence of GD in Eastern Serbia during the civil war. However, most of the studies are retrospective case-control studies and it is quite difficult to evaluate the effect of a given stressful event in different individuals. Moreover, the accuracy in filling self-rated questionnaires or answering standardized interviews may vary widely among patients due to different emotional impact. Therefore, it is difficult to definitely rule out the effect of possible mild, still undiagnosed thyroid hyperfunction already present in the examination period.

Genetic factors such as HLA (Human leukocyte antigen) and CTLA-4 (Cytotoxic T lymphocyte antigen – 4) determine the susceptibility to GD. Stress may lead to immunologic perturbations and may affect the immune response to TSH receptor through modulation of hormones, neurotransmitters and cytokines. A defect of antigen-specific suppressor T-lymphocytes has been proposed to be partially responsible for the initiation of GD. Stress may result in a defect in the immunologic surveillance leading to production of TSH receptor antibodies. In genetically susceptible individuals stress favors the development of GD by shifting the Th1-Th2 immune balance away from Th1 towards Th2. This shifting may affect the onset or course of GD.

However, there are many studies which failed to show any relationship between stress and GD. No significant difference was seen in the number and nature of stressful life events up to six months before the onset of thyrotoxicosis between patients with thyrotoxicosis and nontoxic goiters in the study by Gray and Hoffenberg.Chiovato et al., could not find past or present Graves′ hyperthyroidism in patients with panic disorder.

Diabetes Mellitus

Severe stress may be a risk factor for diabetes. Children aged five to nine years with stress were significantly more likely to be diabetic. However, recent-onset Type 1 diabetics, 15-34 years old reported no major stress factors within the year before diagnosis.Thus stress in early life may be a risk factor for diabetes, but not in young adults.

Gonadal dysfunction

In females stress can lead to anovulation, amennorhea and other menstrual irregularities. Among newly incarcerated women with stress 9% had amenorrhea and 33% had menstrual irregularity.

In males, there can be decreased sperm count, motility and altered morphology.Ejaculatory disorders, impotence and oligospermia may be associated with psychological factors in male infertility.

Psychosocial dwarfism

This is an extreme form of failure to thrive and may be associated with dramatic behavioral abnormalities. Defective GH secretion has been reported with stimulation test. Reversal of GH insufficiency within three weeks of removal from hostile environment has been reported.Munoz-Hoyos et al., observed a conspicuous reduction in the levels of neuroendocrine markers (melatonin, serotonin, β-endorphins and ACTH) in children suffering from affective deficiency, a diminution which was even more noticeable in the children presenting delayed growth. The organic incapability of confronting stress on a genetic basis, and/or the fact of repeated stresses, from exhaustion of the homeostatic mechanisms, could make some groups of patients liable to suffer depressive symptoms associated with a wide range of deleterious consequences in the endocrine system leading to delayed growth.

Obesity

Mental stress leads to chronic activation of the neuroendocrine systems. Cortisol favors central fat deposition, a decrease in the adipostatic signal leptin and an increase in the orexogenic signal ghrelin, inducing increased appetite and food intake. This phenomenon contributes to the current epidemic of obesity. The “stress” genes which have been selected under pressure in ancient environments may have not adapted to the rapid environmental changes of today.

Impact of Stress on Preexisting Endocrine Disorders

Poor glycemic control

In adults the relationship between stress and poor diabetic control is well established.Poor metabolic control has also been reported in children and adolescents with Type 1 diabetes with stress.

Addisonian crisis

Patients with adrenal insufficiency because of various etiologies may develop adrenal crisis on exposure to stress. To prevent this, the replacement doses of steroid need to be doubled during the period of stress

Thyroid crisis

Thyroid storm may be precipitated by physical stress. Acute emotional stress can also precipitate thyroid storm. Yoshiuchi et al., observed that those patients with GD who were stressed for six months after beginning of therapy were significantly and independently associated with the hyperthyroid state 12 months after beginning therapy. Fukao et al., studied the effects of emotional stress and patients′ personality traits on the prognosis of hyperthyroidism in 69 antithyroid drug-treated euthyroid patients with Graves′ hyperthyroidism. They observed a higher frequency of relapse in those who had stress. A retrospective study by Benvenga on GD found that those who had taken benzodiazepine only in the acute phase of thyrotoxicosis relapsed more compared to those who had taken benzodiazepine for a longer period.Vos et al., observed that stress exposure is not related to the biochemical severity of GD, but is directly related to the clinical severity of GD.

The adrenal gland produces androgen and cortisol. It helps to control blood sugar and much more. Learn how the hormones produced by this gland affect many aspects of genetics and it’s role in the endocrine system.Adrenaline is a hormone released into the body of someone feeling extreme emotions, which causes the person to have more energy. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Adrenocorticotropic hormone (ACTH) is a hormone that plays an important role by stimulating the production of cortisol. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Aldosterone plays an important role in cardiovascular health and can be a cause of endocrine hypertension. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Angiotensin is a common name for four hormones and play an important role in blood pressure regulation. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Women are born with their lifetime supply of eggs but these decrease with age. Anti-Müllerian Hormone (AMH) acts as the gatekeeper for fertility and reproductive development. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Calcitonin is one of the most critical hormones, controlling calcium and potassium levels. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Cholecystokinin is most recognized for improving digestion. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Dehydroepiandrosterone (DHEA) is an important precursor hormone. It has little biological effect on its own but has powerful effects when converted into other hormones used for reproduction. Learn what happens if you have too much or too little of this hormone.

Dihydrotestosterone is a hormone that stimulates the development of male characteristics. The amount of dihydrotestosterone present in the body from day to day depends on the amount of testosterone present. Learn what happens if there is too much or too little of this hormone.

Several organs play a major role in helping the endocrine system to work well. Although these organs are not glands themselves, they do produce, store, and send out hormones that help the body to function properly and maintain a healthy balance.

Erythropoietin support the production of red blood cells. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Estradiol is the strongest of the three estrogens and an important player in the female reproductive system and the most common type for women of childbearing age. Learn more about what happens if there is too much or too little of this hormone.

Estriol is an estrogen hormone a minor female sex hormone. It promotes the uterus’ growth and gradually prepares a woman’s body for giving birth. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Estrogen is one of two main sex hormones that women have. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Estrone is one of the three types of estrogens and the only estrogen your body makes after menopause-when menstrual periods stop. Learn more about what happens if there is too much or too little of this hormone.

Gastrin is directly responsible for the release of gastric acid, which breaks down the proteins in the food you eat. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Ghrelin is an important digestive hormone that controls appetite. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Glucagon, a peptide hormone, is produced by the pancreas to regulate glucose in the bloodstream. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Glucagon-like Peptide 1 (GLP-1) is a hormone produced in the small intestine that stimulates insulin production and prevents glucagon production, thereby lowering blood sugar. Learn what happens if there is too much or too little of this hormone.

Gonadotrophin-Releasing Hormone (GnRH) secrete improtant reproductive hormones such as luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Learn how this hormone affects many aspects of your health and how to keep it in balance.

Growth hormone (GH) is a substance that controls your body’s growth. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Ever wonder how are at-home pregnancy tests able to detect if you are pregnant? The Human Chorionic Gonadotropin (HcG) hormone is important in the early stages of pregnancy. Learn how this hormone affects many aspects of your health and how to keep it in balance.

The hypothalamus is in control of pituitary hormones. Learn how the hormones produced by this gland affect many aspects of genetics and it’s role in the endocrine system.

The hormone insulin is essential for life, regulates many metabolic processes that provide cells with needed energy. Understanding insulin, what insulin does, and how it affects the body, is important to your overall health.

Kisspeptin is made in the hypothalamus, is an important hormone that starts the release of several other hormones. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Leptin is a hormone that is crucial to appetite and weight control. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Melanocyte-Stimulating Hormone (MSH) is essential for preserving the skin from ultraviolet rays, the development of pigmentation, and controlling appetite. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Melatonin is a hormone that regulates our sleep and wake cycle and is sometimes used as a supplement. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Norepinephrine is a hormone and a neurotransmitter that increases heart rate and blood pressure, breaks down fat, and more. Learn how this hormone affects many aspects of your health and how to keep it in balance.

The ovaries play an important role in female reproduction and development. Learn how the hormones produced by this gland affect many aspects of genetics and it’s role in the endocrine system.

Oxytocin is a hormone crucial for childbirth and labor, breastfeeding, and social behaviors and bonding. Learn how this hormone affects many aspects of your health and how to keep it in balance.

The main function of the pancreas is to maintain healthy blood sugar levels. Learn how the hormones produced by this gland affect many aspects of genetics and it’s role in the endocrine system.

The parathyroid is important in bone development. Learn how the hormones produced by this gland affect many aspects of genetics and it’s role in the endocrine system.

The parathyroid hormone affects your calcium levels in the bones, intestines and kidneys. Learn how this hormone affects many aspects of your health and how to keep it in balance.

How is your body able to recognize when you have eaten enough food? After eating, the hormone peptide YY (PYY) is produced by the small intestine and released into your bloodstream. Learn how this hormone affects many aspects of your health and how to keep it in balance.

The pineal gland and its importance for your sleep cycle. Learn how the hormones produced by this gland affect many aspects of genetics and it’s role in the endocrine system.

Progesterone is a female hormone that regulates the menstrual cycle and is crucial for pregnancy. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Prolactin, or luteotropin, is the hormone that helps mammals produce milk. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Prostaglandins are lipids that aid in recovery at sites of tissue damage or infection. Learn how this hormone affects many aspects of your health and how to keep it in balance.

When a woman is ready to deliver a baby her body produces the hormone relaxin. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Have you ever wondered what hormone is responsible for your mood and feelings? Serotonin is the key hormone that stabilizes our mood, feelings of well-being, and happiness. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Somatostatin is also called SS, SST or SOM. This growth hormone inhibitory hormone affects several areas of the body by hindering the secretion of other hormones. Learn how this hormone affects many aspects of your health and how to keep it in balance.

The testes play an important role in male development. Learn how the hormones produced by this gland affect many aspects of genetics and it’s role in the endocrine system.

Testosterone is an important male sex hormone. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Thymus plays an important role during puberty. Learn how the hormones produced by this gland affect many aspects of genetics and it’s role in the endocrine system.

The thyroid gland releases triiodothyronine (T3) and thyroxine (T4). These hormones play an important role in regulation of your weight, energy levels, internal temperature, skin, hair, nail growth, and more. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Thyroxine aids in digestion, heart and muscle function, brain development, and bone maintenance. Learn how this hormone affects many aspects of your health and how to keep it in balance.

Bibliography

https://www.nhs.uk/conditions/vitamins-and-minerals/

https://www.news-medical.net/health/What-are-Hormones.aspx

https://www.britannica.com/science/hormone/The-hormones-of-vertebrates

https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/hormonal-endocrine-system

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3079864/

https://en.wikipedia.org/wiki/List_of_human_hormones

https://en.wikipedia.org/wiki/Hormone

https://www.hormone.org/your-health-and-hormones/glands-and-hormones-a-to-z

https://www.brainkart.com/article/Deficiency-of-Vitamins_2091/

https://www.lkouniv.ac.in/site/writereaddata/siteContent/202003291612341624kuaum_yadav_structure_and_properties_of_Vitamins.pdf