A vitamin is a nutrient that is required in tiny amounts and is essential for smooth metabolic reactions to take place in your body. Most of these vitamins cannot be produced by the body, and therefore they must be obtained from your diet.
Vitamins are essential for the normal growth and development of human beings. Vitamin deficiencies may be primary or secondary. A primary deficiency is when you do not get enough vitamins through your diet whilst a secondary deficiency is when an underlying disorder prevents or limits the absorption of the vitamin into your body.
This could be due to you making damaging lifestyle choices such as smoking, excessive alcohol or certain medications that could interfere with the vitamin working as usual. The best way to maintain a healthy flow of vitamins in your body is to eat a wide variety of foods. This ensures that you will never suffer from primary vitamin deficiency.
On the other hand, a restrictive diet that is generally associated with weight loss can cause prolonged vitamin deficits and these can lead to painful and even perhaps deadly diseases. Therefore, it is crucial that you increase your intake of vitamins when trying to lose weight. It is also important to realize that human bodies are unable to store most vitamins and that you must therefore consume vitamins on a regular basis to avoid deficiency.
Dietary supplements containing vitamins are used to ensure that the required amounts of nutrients are obtained on a daily basis, if the right amounts of the nutrients cannot be obtained through a varied diet.
Vitamins are found in a wide variety of foods and they fulfil many general or specific functions. These are the catalysts that spark off essential bodily processes or ensure that they work successfully. They also help to protect the body against infection, diseases and damage, and maintain general good health.
Vitamins are grouped into water-soluble types – vitamins C and B group – and fat-soluble types – vitamins A, D, E and K.
The body does not store water-soluble vitamins for any length of time and excess intakes are excreted, so the diet must include regular supplies. These vitamins also seep out of food into cooking liquids. They are sensitive to heat and light, and the levels in food diminish with staleness.
Even though the fat-soluble vitamins are stored in the body, they are still required regularly but they can be eaten to excess. These vitamins are not as easily lost during food preparation and boiling, but they are lost with fat during roasting, frying and grilling.
Found in fruit and vegetables. It is essential for healthy tissue and known as the vitamin that is vital for good skin. It is necessary for the process of absorbing and utilizing other nutrients, usch as iron. Vitamin C is also an antioxidant, helping to protect the body and repair any damage caused by free radicals.
The B-Group vitamins are important for the metabolism, the breaking down, absorbing and using of food. They also fulfill other vital tasks, including maintaining a healthy nervous system and generating red blood cells.
Vitamin B1 or thiamin
Found in meat and offal, whole grains, nuts, beans and pulses. It is important for the nervous system and in ensuring that the body can release and use energy from food.
Vitamin B2 or riboflavin
Found in meat, offal eggs, milk and its products, fish, fortified cereals, and flours. Riboflavin helps the body to release and use energy from food. Riboflavin is light-sensitive – so the content of this vitamin diminishes in milk which is left to stand in the sun.
Niacin or nicotinic acid
Found in poultry, meat, fish, nuts and vegetables. It is essential for cell function and for passing messages through the nervous system. It is important for the release and use of energy.
Vitamin B6 or pyridoxine
Found in many foods, including fish, poultry, meat, vegetables, cereals, nuts and yeast extract. It is important for the formation of red blood cells, for a healthy immune system and for breaking down protein.
Vitamin B12 or cobalamin
Found in animal foods, including fish, poultry, meat, eggs and diary produce. It is also found in fortified breakfast cereals. This vitamin is essential for producing DNA and so it is vital for all cell generation, including the formation of red blood cells. Since it is widely available in foods, deficiency is rare. However, those following a vegan diet, excluding all animal products, are vulnerable.
Folate or folic acid
Found in green vegetables, liver, wheatgerm and fortified cereals. It is essential for the production of red blood cells and all DNA.
Found in most foods, including meat and offal, vegetables, dried fruit and nuts. It assists in the release of energy and the manufacture of red blood cells, cholesterol and fat.
Vitamin A or retinol
Found in animal foods, such as oily fish, liver, milk and its products, and eggs. Beta carotene is converted into vitamin A in the body; it is found in highly coloured fruit and vegetables, including carrots, red and orange peppers, mango, apricots and green leafy vegetables.
Vitamin A is important for healthy eyes and good night vision, as well as cell construction, the mucous membranes in the eyes, and for the respiratory and digestive tracts. Vitamin A promotes healthy skin and is used for general cell building.
Found in liver, oily fish, eggs and fortified margarine. It is also synthesized in the body during exposure to sunlight. Deficiency is rare, except in those who are confined indoors, such as the elderly. Vitamin D is important for calcium and phosphorus absorption, therefore for healthy bones and teeth.
Found in vegetable fats and oils, including nuts, seeds, oils and avocado. It is an important antioxidant, protecting the body from damage caused by free radicals.
Found in green leafy vegetables. It is important for the normal clotting of the blood.
Minerals or dietary minerals are chemical elements that our body needs, apart from the elements carbon, hydrogen, nitrogen and oxygen. There are two main kinds of dietary minerals that are known as macro minerals and trace minerals.
Minerals assist with specific and general functions throughout the body. While some minerals are only required in small amounts, they are still important and the body must have an adequate supply to function well.
Found in milk and milk products, sardines and other fish where the bones are normally eaten (such as canned salmon), shellfish, dark leafy green vegetables and sesame seeds. Oxalic acid in spinach and phytic acid in the outer layers of whole grains inhibit the absorption of calcium. Vitamin D is also essential for calcium absorption. Calcium is important for healthy bones and teeth.
Found in a wide range of foods and deficiency is rare. Liver, shellfish, nuts and mushrooms all provide copper. It is important for iron absorption, the manufacture of red blood cells and connective tissue, and it helps protect the body against damage from free radicals.
Found in fish, although the main dietary source, to varying degrees, is water, depending on soil and local policies on the fluoridation of tap water. It is important for the enamel coating on teeth and for healthy bones but an excess can be damaging, causing the over formation or hardening of bones.
Found in seafood, including seaweed, vegetables and fruit. The level of iodine in food depends on the soil, with more in coastal areas. Iodine is essential in small amounts for a healthy thyroid gland and the levels of hormone it produces to control energy production as well as growth and development. Iodine deficiency leads to an under-active thyroid gland, one of the symptoms of which is a general lack of energy.
Found in meat and offal, egg yolks and green leafy vegetables. Iron from vegetables, such as spinach and watercress, is not as easily absorbed as that from animal sources. Vitamin C aids iron absorption, so it is helpful to combine foods rich in vitamin C with those rich in iron. The body limits the amount of iron that it will absorb and store, so the diet must include a regular supply. Iron is important for haemoglobin or red blood cell production and for the proper functioning of enzymes.
Found in diary produce, grains, pulses, green vegetables and nuts, as well as many other foods. Deficiency is rare in a good, mixed diet. It is important for enzyme activity and the function of the nervous system and muscles.
Found in plant foods in levels that depend on the amount in the soil. It is obtained from whole grains, pulses and nuts. Its roles include enzyme activity, proper thyroid function, insulin production, and muscle and nerve function. Deficiency is rare in a healthy, mixed diet.
Widely distributed in plant foods and liver, and deficiency is rare. It is important for proper enzyme function.
Found in animal foods, plants and whole grains, and deficiency is rare. It is vital for healthy bones and teeth, and for energy production. It is also found in, and is important to the function of, body proteins. It is so widely available that deficiency is rare but it can be eaten to excess.
The phosphorus and calcium in the diet should be balanced, as too much phosphorus can cause the body to reduce its calcium absorption, resulting in calcium deficiency. Phosphorus and calcium are found in the same natural foods; however, phosphorus is found in processed foods in the form of phosphates (compounds of phosphorus), and diets with a high content of processed foods, rich in phosphates but low in calcium, can lead to an imbalance.
Found in most foods, specially meat, whole grains, vegetables, celery, citrus fruit and bananas. With sodium, potassium is important for bodily fluid balance and efficient nerve and muscle activity.
Widely available in fish, meat, offal, diary produce, citrus fruit, grains and avocados. Levels in plant sources relate to those in the soil. Selenium plays roles in hormone activity, growth and development. It is important for healthy eyes and hair, and as an antioxidant, helping to protect against damage from free radicals.
Found in sodium chloride or salt. It is essential, with potassium, for balancing fluid levels in the body, and for nerve and muscle function. Salt is so widely used that diets can have too high a sodium content, especially when lots of processed and prepared products (generally containing lots of salt) are eaten regularly. A very high salt content contributes to the problem of high blood pressure. Sodium is lost in sweat, so levels have to be replenished.
A compound found in proteins, so it is available from animal foods, fish and pulses. It is important in body proteins, including skin, hair, nails and connective tissue, and vital to many of the body’s hormonal functions.
Found in fish and shellfish, as well as all animal foods and whole grains. Zinc in animal foods is more readily absorbed than that in vegetable sources. It is important for enzyme activity of the immune system, as well as for night vision, taste and digestion, and energy production.