Benefits, Uses & Side Effects of Vitamins Supplements

Before the 19th century, one of the hazards of long sea voyages was a condition called scurvy, whose symptoms were loss of hair and teeth, bleeding gums, very slow healing of wounds, and eventually death.

Hundreds of sailors and explorers died from scurvy until a Scottish physician, James Lind, in the 1750s discovered that adding a daily portion of citrus fruit to the rations of those at sea could prevent the condition, whereas adding cider, vinegar or various other substances that he tested, could not. 

In those days, it was considered that a disease was caused by something bad in the diet, or in the air, but not by the absence of something good, so despite Lind’s evidence, his ideas were not accepted by his fellow physicians. 

Additionally, he was unable to confirm his work by experiments on land since, although he tried to restrict the types of food eaten by a group of volunteers to attempt to produce scurvy in them, he was unable to do so, probably because it can take several months for the condition to develop, and in that time his volunteers occasionally cheated on their diet. 

However, though he died disillusioned, Lind had actually discovered the importance and source of vitamin C.

Before their detailed chemical structures were known, vitamins were named by being given a letter. They are generally still referred to by that letter and their chemical name; for example, vitamin C or ascorbic acid. 

There are two main groups of vitamins: fat-soluble vitamins and water-soluble vitamins. The body can store fat-soluble vitamins, but any excess water-soluble vitamins are easily removed from the body in the urine, so regular intake is necessary. Vitamins are, however, needed in only very small quantities.

The daily requirement of certain vitamins is much less than 1 mg (1mg is one-thousandth of a gram), and so is measured in micrograms per day, written as μg per day, where 1 μg is one-thousandth of a milligram. 

Vitamin A

Vitamin A is toxic if taken in very large quantities and poisoning has occurred in Arctic explorers who have eaten polar bear liver, which is particularly rich in vitamin A. 

The concentration of vitamin A in lamb and calf liver has increased substantially in the last 20 years due to supplements to their feed. Pregnant women are advised to restrict their intake of liver and pâté made from the liver since there is some evidence that high doses of vitamin A can cause birth defects. 

However, vitamin A is an essential part of the human diet and severe health problems occur if there is a deficiency. Since dairy products, such as butter, are a good source of vitamin A, all types of margarine and similar spreads are now required by law to have vitamin A added to them, as you will see on their labels. 

Vitamin A, which is actually a group of interrelated substances (retinol, retinal and retinoic acid), can be synthesised in the body from β-carotene, found in dark-green leafy vegetables such as cabbage, sprouts, broccoli and spinach, and in carrots. 

Cooking vegetables does not damage the β-carotene molecules and in fact β-carotene is more easily absorbed into the body from cooked carrots.

Retinal is found in the cells of the eye where it plays a vital part in the perception of light and this is why the ‘old wives’ tale’ that carrots help you see in the dark is, in fact, true. 

The speed at which the human eye adapts to seeing in the dark depends on the amount of vitamin A available in the body, known as the vitamin A status. A ‘dark adaptation test’ can be used as a measure of vitamin A status. Vitamin A deficiency is a major public health problem in the developing world, causing blindness in a quarter of a million people each year. 

Vitamin A supplements are successful in preventing blindness from this cause. Vitamin A also assists in keeping the epithelial cells of the body moist and healthy. As well as lining the whole of the digestive tract, epithelial cells cover the surfaces of the glands around the eyes and line the lungs (and are found elsewhere too). 

Xerophthalmia or dry-eye is a classic sign of vitamin A deficiency. Tear production is reduced and the eyes become susceptible to infections such as conjunctivitis. Children who are vitamin

A-deficient people are more susceptible to respiratory infections and measles. Vitamin A is involved in normal growth and bone formation and it plays a part in the production of red blood cells and therefore the prevention of anaemia.

In order to understand another important role of vitamin A and other vitamins, as antioxidants, you need to know a little more about the internal structure of atoms. Atoms sometimes carry a positive or a negative (+ or−) charge. 

These charges arise because atoms are made up of positively charged particles called protons and negatively charged particles called electrons. The protons, along with uncharged particles called neutrons reside in the core of the atom as part of the atomic nucleus. 

For the purpose of this simple description, you can think of the electrons as tiny spheres that are in orbit around the nucleus. Normally, the numbers of protons and electrons in any particular atom are the same, so the positive and negative charges are balanced, and overall the atom has no charge.

However, if an atom gains an electron, it has one extra negative charge (since it now has one more electron than it has protons), and so we would write a − sign beside it, and if it loses an electron, it has a positive charge (since it now has one more proton than it has electrons), and we would write + beside it. 

When atoms bond together, they can share pairs of electrons, one from each atom, so when we have been talking about a bond between two atoms (the atoms ‘holding hands’), we have actually been referring to these electron pairs.

However, sometimes a molecule can be formed in which there is an atom with a single free electron, and this type of molecule is called a free radical. Free radicals are extremely reactive and the problem is that as they react, they create more and more free radicals in a runaway chain reaction. 

This process happening within cells involves atoms in molecules such as DNA that are vital to the cell’s functioning, and it can have serious health consequences. The precise way in which free radicals cause the damage attributed to them is not fully understood, but they are implicated in many human diseases and disorders. 

Many pollutants generate free radicals, as does smoking, and free radicals are probably the link between exposure to toxins and the development of cancer.

Certain molecules have the ability to donate electrons to free radicals, while not themselves being destroyed or becoming free radicals. 

Thus they can safely interact with free radicals and terminate the chain reactions before vital cell components are damaged or destroyed. Such molecules are known as antioxidants, and vitamin A is one of the important antioxidants in the body.

Vitamin D

The main role of vitamin D is to facilitate the uptake of calcium from food, through the lining of the small intestine into the blood. It also controls the deposition of calcium in the bones during growth and maintains adult bone structure. 

If vitamin D is deficient, with less calcium available, the skeleton fails to develop normally. The most obvious symptom is the bowing of the leg bones in children, producing the condition called rickets. 

Children with vitamin D deficiency grow more slowly and may become smaller adults which, in women, has serious consequences because the pelvis may end up so small that giving birth normally is impossible. 

Vitamin D deficiency in adults is called osteomalacia. Rickets and osteomalacia were relatively common in Europe during the 19th century, especially in urban slums.

A generation or two ago, a regular dose of cod liver oil was given to children to prevent rickets. Levels of vitamin D in dairy products vary throughout the year but it is now added to margarine and many low-fat spreads, providing an all-year-round supply. Breakfast cereals, yoghurts and food for babies and infants are often also ‘fortified’ with vitamin D.

However, there is some debate as to whether vitamin D should actually be classified as a vitamin since it does not fit completely with the usual definition, which is that vitamins are obtained from the diet. It is not essential to obtain vitamin D in the diet. 

It can be synthesised below the surface of the skin in the presence of ultraviolet (UV-B) light. However, in the UK, there is insufficient UV-B in sunlight between October and March for synthesis to occur, although most people probably make and store enough in the body during the summer months to last through the winter.

In fact, the beneficial effect of sunlight, in playing a part in vitamin D synthesis, has to be balanced with the detrimental effect, its role in causing skin cancers. 

It appears that an exposure to sunlight of about 30 minutes per day (avoiding the part of the day when sunlight is strongest) is an appropriate balance between the harmful and beneficial effects.

Although rickets has largely been eliminated in the UK, due to the addition of vitamin D to food especially for infants and children, the condition has reappeared in Asian communities in the UK, especially in the more northern parts of the country.

Vitamin E

Vitamin E is not a single compound but consists of a group of eight closely related chemicals, of which the most important, responsible for about 90% of its activity in the body is alpha-tocopherol. 

Since, like vitamins A and D, vitamin E is fat-soluble, it occurs in fat-rich foods. The main sources in the UK diet are plant oils such as soya, corn and olive oil. Other good sources include nuts and seeds, and wheatgerm (the part of the wheat grain that will develop into the new plant) and some green leafy vegetables. 

It is added to some margarines and spreads. The main role of vitamin E in the body is as an antioxidant.

Vitamin E is particularly important in maintaining cell membranes in a healthy state. Its presence appears to be particularly significant in the lungs, red blood cells, heart and brain, though deficiencies are rare and few human conditions can be specifically related to its absence.

However, fewer cases of heart disease and cancer occur in people whose vitamin E intake is adequate. There is, as yet, no clear evidence that taking in additional vitamin E gives additional protection against these conditions and supplements are not advised.

Vitamin K

Like vitamin E, vitamin K is fat-soluble and composed of a series of related compounds. Vitamin K is widely distributed in the diet and it is absorbed from the small intestine with the assistance of bile acids. 

Vitamin K is also manufactured by the bacteria that inhabit the human large intestine and appears to be absorbed there too. The main role of vitamin K is in blood clotting. This process requires the presence of a number of different chemicals, called clotting factors, in the blood. 

A number of these (including prothrombin and Factors VII, IX and X) require vitamin K in their synthesis. Deficiency could therefore result in an increasing tendency to bleed. Vitamin K also plays a role in the formation of bone and supplements can be effective in increasing bone density in Osteoporosis.

There is a rare condition called vitamin K deficiency bleeding which occurs in about 1 in 10 000 babies in the first few weeks of life. Many babies who have this condition die or sustain significant brain damage due to bleeding into the brain. 

The condition occurs almost exclusively in breastfed babies, since human milk contains very little vitamin K, whereas it is added to formula milk. It is almost completely preventable by giving a single injection of vitamin K soon after birth, and such injection has been given routinely to UK babies since the 1960s.

However, two papers in the early 1990s suggested an association between the vitamin K injection and a very slight increase in the incidence of childhood leukaemia. This discovery led, in some countries, to vitamin K being offered as an oral dose instead. 

However, vitamin K by mouth was less effective than the injection at preventing vitamin K deficiency bleeding, which still occurred in 1 in 100 000 babies. Other research has not supported the link between vitamin K and leukaemia and a study published in 2004, which looked at 4000 cases of childhood cancers, found no association with the injections of vitamin K. 

In the UK now, new mothers may be given the choice of a vitamin K injection or a course of oral doses for their newborn baby.

Vitamin B

Vitamin B, often called the vitamin B complex, consists of a whole range of different compounds, some of which have similar functions and work together. However, unlike the families of compounds forming vitamins E and K, the B vitamins are sufficiently different from one another to be given individual names or numbers and to be listed separately on many food labels. 

Except for vitamin B12, the body can only store limited amounts of B vitamins and because they are all water-soluble, any excess is excreted in the urine. Their water-solubility also means that B vitamins are easily lost in cooking, and they can also be destroyed by light and exposure to air.

Thiamin (or thiamine, also known as vitamin B1 )

The deficiency disease beriberi has been known for thousands of years. The name literally means ‘I can’t, I can’t’ in Sinhalese (a major language in Sri Lanka), and reflects the crippling effect on its victims, who suffer from neurological symptoms, including pain, fatigue and paralysis, and cardiovascular disease. 

The disease was most common in southeast Asia, where white or ‘polished’ rice was a major part of the diet. The main source of thiamin is in the outer layers of the grain, the bran, which is removed during milling to produce white rice grain and white rice flour.

Thiamin is added to white flour in the UK and many breakfast kinds of cereal are also enriched in thiamin. It is present in seeds, nuts and in beans and in smaller quantities in other foods such as meat, milk and potatoes. 

Since potatoes are eaten frequently in the UK diet, they can form a useful source, though thiamin is gradually destroyed by boiling water and it is estimated that 20% of the possible dietary intake is lost in cooking.

Thiamin is essential in many of the metabolic pathways in the body, especially in the processing of carbohydrates to provide energy. Since the nervous system relies almost exclusively on carbohydrate (glucose) for its energy, it is not surprising that the symptoms of deficiency are seen there. 

Because, as a water-soluble vitamin, little thiamin can be stored in the body, symptoms appear in less than a month on a diet in which it is completely absent. The early symptoms can, however, be rapidly corrected by regular intake of thiamin.

There are two forms of beriberi, known as the ‘wet’ and ‘dry’ forms. In ‘wet’ beriberi, there is swelling of the limbs, increased heart rate, lung congestion and an enlarged heart, all symptoms of heart failure, which can ultimately be fatal. 

The symptoms of ‘dry’ beriberi include pain, tingling and loss of sensation in the hands and feet, muscle wasting and gradual loss of function and paralysis of the legs, brain damage and eventually death. 

Nowadays, with better nutritional information and the addition of thiamin to many foods, beriberi is rarely seen, except in people with alcoholism, who mainly have the ‘dry’ form, in a condition called Wernicke-Korsakoff syndrome. 

Chronic alcoholism is often associated with poor nutrition and therefore a low intake of thiamin.

Additionally, alcohol appears to interfere with thiamin absorption from the gut. The symptoms of Wernicke-Korsakoff syndrome begin with peripheral nerve damage (loss of feeling in hands and feet), then damage to the central nervous system and finally a confused mental state, or psychosis, which affects mood, language and thinking.

Because of its involvement in carbohydrate metabolism, additional thiamin may be needed during pregnancy, lactation and also in cancer patients and in people on kidney dialysis. It has been suggested that additional thiamin could be beneficial to performance in certain sports, but experiments so far have produced no evidence to support this idea.

Riboflavin (vitamin B2 )

Riboflavin or vitamin B2, which was originally known as vitamin G, is found in a wide variety of foods, including milk and dairy products. It is more stable to heat than some of the other B vitamins but is destroyed by exposure to sunlight. 

Milk in a glass bottle exposed to the sun loses 10% of its riboflavin per hour. Riboflavin plays a crucial role in the metabolism of carbohydrates and proteins and is involved in many other metabolic reactions in the body.

Although riboflavin deficiency does occur in some parts of the world, it is usually associated with deficiencies in other B vitamins and a specific deficiency syndrome is hard to identify. The clearest signs of deficiency are in the mouth, with cracks and inflammation at the corners, sore and ulcerated lips and a painful tongue. 

Other signs are detected in the eyes, with increased sensitivity to light and burning and itching sensations.

Niacin (vitamin B3 )

Niacin, which comprises two compounds, nicotinic acid and nicotinamide, also occurs widely in food and is added to many breakfast kinds of cereal. It is easily absorbed into the blood from the digestive system and plays a vital role in energy production in cells. 

It appears to reduce the levels of low-density lipoproteins or LDLs in the blood and increase high-density lipoproteins or HDLs, perhaps by affecting the proteins that carry the fats.

This is important because LDLs are a way of transporting cholesterol around in the blood. Cells that need cholesterol take it up from LDLs. If cells contain excess cholesterol, it is returned to the blood packaged into HDLs. 

The higher the ratio of HDL to LDL in the blood, the lower the risk of developing heart disease. Thus, if niacin increases HDLs and reduces LDLs, this should give some protection against heart disease.

The deficiency disease associated with a lack of niacin is pellagra. Its symptoms are the four Ds – diarrhoea, dermatitis, dementia and death, normally experienced in that order! The term ‘pellagra’ was first used in 1771 to describe the disease that was endemic at that time in poor populations in southern Europe. 

‘Pellagra’ is from the Italian words Pelle meaning ‘skin’ and agro meaning ‘sour’ and refers to the thickened, roughened skin, or dermatitis, which is characteristic of the disease.

It was noticed that people with pellagra subsisted on a diet that was based on maize and contained very little meat. By 1900, the disease had spread to France, Egypt and England, and in 1902 it was first reported in America. 

For the next 20 years, it reached epidemic proportions in the southern USA. Again, poverty and the consumption of large quantities of maize (corn) appeared to be the risk factors. Although it was soon realised that the deficiency disease could be prevented by the inclusion of meat in the diet, it was not until the late 1930s that the explanation of the link with eating a lot of maize was understood.

This link involves a molecule called tryptophan. Tryptophan is an amino acid, one of the molecules that make up proteins, and is commonly found in animal proteins. Niacin can be synthesised in the body from tryptophan. 

In fact, in the average UK diet, there is probably sufficient protein to satisfy all the niacin requirements of the body, and dietary niacin is therefore not essential. However, maize contains so little tryptophan that it is insufficient for the body to convert to niacin. Additionally, any niacin present in the maize itself is so tightly bound to molecules in the maize which are not digested, that it cannot be absorbed by the body. 

In the indigenous populations of Mexico and Central America, who also subsist on a diet of maize, there have been almost no occurrences of pellagra. It seems that their tradition of soaking the maize in an alkaline solution of lime before cooking it, releases the bound niacin, freeing it for absorption by the body. 

Poor peasants of the Deccan Plateau of India, however, do suffer from pellagra, although their staple carbohydrate is millet (sorghum) rather than maize. This grain contains sufficient tryptophan but it also contains very high levels of leucine, another amino acid that has been found to prevent niacin synthesis in the body, so symptoms of its deficiency occur. 

People with HIV infection can also suffer from a pellagra-like condition since the infection causes the tryptophan levels in their blood to be very low. High doses of niacin can reverse the pellagra condition.

Vitamin B6 (pyridoxine)

Vitamin B6 is composed of pyridoxine and two closely related compounds. It is found in small quantities in many foods, though it can be destroyed in the cooking process. 

No clear deficiency disease has been recognised in humans as being directly caused by lack of this vitamin since it is often found in conjunction with other B vitamins and their absence has greater effects. Its main role is in the conversion of some amino acids into other ones, depending on the requirements of the body.

It also plays a role in fat metabolism (in the conversion of linoleic acid to arachidonic acid) and in carbohydrate metabolism. Thus, deficiency causes generalised problems such as anaemia, dermatitis and neuromuscular problems such as headaches, aching muscles and difficulty in walking. 

There is some evidence that low doses of vitamin B6 can be helpful in improving the symptoms of premenstrual syndrome (PMS), even when there is no evidence of deficiency in the diet.

Folate (folic acid, vitamin B9 )

Folate is a generic name for a group of related compounds. The name ‘folate’ was based on the word ‘foliage’, after it was identified in a crude extract from spinach, though it is also found in liver, other green vegetables, oranges and potatoes and it is often added to breakfast cereals (usually listed as folic acid). 

Folate is less sensitive to heat than many of the B vitamins, though it is destroyed if food is reheated or kept hot for long periods. Folate is involved in amino acid metabolism, but its crucial role is in cell division since it is used in DNA synthesis. 

So deficiency of folate has its major effect on dividing cells, especially those in the bone marrow (which produces red blood cells) and those lining the digestive system. Failure of normal cell division in the cells lining the digestive system can lead to loss of appetite, nausea and diarrhoea, and soreness in the mouth. 

Failure of normal cell division in the bone marrow leads to a type of anaemia called megaloblastic anaemia, where large, immature blood cells which do not have the normal oxygen-carrying capacity, are released into the circulation. After iron deficiency, folate deficiency is the next most common cause of anaemia.

Due to the huge amount of cell division that goes on in the first few months of pregnancy, pregnant women need as much as five times more folate than the normal daily requirement. Up to 25% of women would show changes in their bone marrow that are characteristic of folate deficiency if they did not increase their intake. 

Folate also appears to be important around the time of conception. For this reason, women planning to become pregnant are now encouraged to take folate supplements for about three months before conception and for the first three months of pregnancy. 

There appears to be a link between lack of folate and neural tube defects such as spina bifida, where the spinal cord does not develop correctly in the early fetus. Several studies have shown that giving folate supplements to women who have previously given birth to a child with a neural tube defect can reduce the risk of the same problem arising in a subsequent pregnancy by almost 75%.

There is some evidence that folate deficiency is also linked with increased risk of cardiovascular disease and with cancer, but more work is needed in both these areas. 

Alcohol affects the uptake of folate from the digestive system into the blood, so alcoholics are at risk of folate deficiency for this reason as well as because their diet may be lacking in folate. 

Other population groups who do not have a balanced diet, due to poverty, poor food choices, or illness, may also be at risk. Some commonly used drugs, including aspirin, indigestion remedies and the contraceptive pill, together with some antibiotics and anti-epilepsy drugs, may affect folate uptake too, and smokers may need additional folate.

Chemotherapy drugs used in cancer treatment can also cause folate deficiency. In fact, folate deficiency is probably the most common vitamin deficiency seen in the developed world.

Vitamin B 12 (cobalamin)

Vitamin B12 is yet another group of compounds, this time with an atom of the metal called cobalt (present in only trace quantities in the body) in their structure, hence the alternative name ‘cobalamin’. 

Vitamin B12 works alongside folate and if levels of it are low, folate deficiency symptoms occur too. It is stored in the liver and in general, the body does not appear to need a regular intake. Many people have enough B12 stored in their liver to last for up to 30 years. 

Unlike most vitamins, vitamin B12 is found only in foods obtained from animals. In ruminant animals such as cattle and sheep, the bacteria in their stomachs synthesise vitamin B12, hence its presence in their meat, milk and dairy products. 

Due to its ability to boost metabolism and provide lasting energy, B12 is often associated with weight loss. For example, the popular weight loss supplement Meticore’s ingredients also include vitamin B12 because it can convert the food we eat into sugar and other types of fuel that keep the body running smoothly. You might read some Meticore reviews if you are interested in the natural fat burner.

They too store it in their liver and hence eating liver is a rich source of the vitamin. Vegetarians are likely to take in sufficient vitamin B 12 due to contamination of their food by yeasts and bacteria, but strict vegans may need to supplement their diet to ensure sufficient intake. If the diet contains excessive amounts of vitamin C, this can bind to vitamin B 12 and limit its availability. 

Vitamin B12 is essential for the formation of the protective coating of myelin, which is found around some nerve fibres (neurons) and so its deficiency can lead to malfunction of the nerves and eventual paralysis and dementia. Like folate, vitamin B12 is also vital for cell division, especially in the bone marrow, since it also plays a role in DNA synthesis.

The deficiency of vitamin B 12 due to dietary insufficiency is uncommon, but this vitamin can be deficient due to a condition that prevents its normal absorption. Because the B 12 molecule is particularly large, in order to be absorbed by the body it has to be linked to a protein known as ‘intrinsic factor’, which is produced by the lining of the stomach. 

The combined ‘complex’ is then absorbed into the blood when the food reaches the small intestine. If the cells that produce intrinsic factors are destroyed, or the intrinsic factor is inactivated, vitamin B12 cannot be absorbed. 

This situation may occur due to an autoimmune disease in which the body produces antibodies against the cells that produce the intrinsic factor or against the intrinsic factor itself. Women are more commonly affected than men and this type of autoimmunity tends to run in families. 

The intrinsic factor-producing cells can also fail to function efficiently in a patient with ulcers, stomach cancer or other conditions such as Crohn’s disease that affect the digestive system. 

The condition that results in all these cases is called pernicious anaemia, for which the treatment is regular injections of vitamin B12.

Pantothenic acid (vitamin B5 )

The name ‘pantothenic acid’ is derived from the Greek pantothen which means “from all sides”, indicating that it is widely distributed in the diet. It plays a vital role in metabolism, particularly in the production of energy in cells. 

Naturally occurring pantothenic acid deficiency is very rare, since it is so widespread in the diet. However, during World War II, prisoners in the Philippines, Burma and Japan suffering from severe malnutrition did experience numbness, tingling and painful burning in their feet, which was relieved specifically by pantothenic acid. 

In mice and rats, pantothenic acid deficiency led to their fur turning grey, and on the basis of this finding, pantothenic acid has been added to some shampoos, in the hope that it might prevent grey hair in humans. There is as yet no evidence that it does.

Biotin (vitamin H)

Although biotin is usually considered to be a member of the B vitamin complex, it is also sometimes known as vitamin H. Like pantothenic acid, it plays a major role in metabolism. 

Deficiency is not normally seen, though it can be induced in rats and people by them eating large quantities of raw egg white. This binds biotin and prevents it being absorbed. Various symptoms result, including hair loss, dermatitis, depression and lethargy.

Vitamin C (ascorbic acid)

Although we tend to think of scurvy as a disease of sailors long ago, it does still occur in refugee camps where the diet contains insufficient vitamin C, and among homeless people in the UK. 

Vitamin C is found in vegetables and fruit, especially blackcurrants and oranges. Potatoes are a good source too, though in the modern diet, more is probably obtained from fresh fruit and from fruit juices. Most mammals can synthesise their own vitamin C from glucose and so do not need it in their diet. 

However, along with humans and most other primates, guinea pigs lack this synthetic capacity. So some of the early research into vitamin C requirements was done on them, which is how ‘guinea pig’ came to mean a test subject in popular speech.

Vitamin C is very soluble in water. It is amongst the least stable of the vitamins and is rapidly destroyed by exposure to light and to air and by heating.

Vitamin C is readily absorbed from the digestive system and the total amount present in the body is typically about 2–3 g. Scurvy results when total body reserves fall below 300 mg.

Vitamin C takes part in many of the body’s metabolic processes and acts as an antioxidant (destroying free radicals). Vitamin C also appears to be beneficial to the immune system and there is evidence that moderate doses alleviate the symptoms of colds, though there is no convincing evidence that large doses can actually prevent colds. Many studies indicate that higher intake of vitamin C is linked with a lower risk of disease in general.

Apart from that, Vitamin C is used in the production of collagen, which is found in large quantities in bone, tendons, cartilage and skin, and in smaller amounts in other tissues. 

It is important in enhancing the absorption of iron (which is needed for red blood cells) from vegetable sources.

I have also reviewed a lot of other dietary supplements, if you are interested, you might check them out.

Key points about vitamins

  • Vitamins A, D, E and K are fat-soluble; the remainder is water-soluble.
  • Adequate amounts of vitamins are required, many on a regular basis, though some can be stored.
  • A balanced diet should provide the necessary amounts of vitamins, but people on a restricted diet need to take particular care to ensure an adequate intake of all of them.
  • Deficiency diseases can occur when vitamins are absent or in short supply.
  • Water-soluble vitamins are easily lost during cooking and are destroyed by exposure to air and light, so care is needed in food preparation to preserve them.

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