importance of vitamins in nutrition

The importance of Vitamins in nutrition

The word ‘ Vitamine’ meaning a vital amine was proposed by a Polish Researcher, Dr. Cacimir Funk, in 1911 to designate a new food substance that cured beriberi. Other terms were proposed as new factors were discovered. But the word vitamin, with the final ‘e’ dropped, met with popular favor.

Vitamins are potent organic compounds that are found in small concentrations in foods. They perform specific and vital functions in the body’s chemistry. They are like electric sparks that help to run human motors. Except for a few exceptions, they cannot be manufactured or synthesized by the organism, and their absence or improper absorption results in a specific deficiency disease. It is not possible to sustain life without all the essential vitamins. In their natural state, they are found in minute quantities in organic foods. We must obtain them from these foods or dietary supplements.

Vitamins, which are of several kinds, differ from each other in physiological function, chemical structure, and distribution in food. They are broadly divided into two categories, namely, fat-soluble and water-soluble. Vitamins A, D, E, and K are all soluble in fat and fat solvents and are, therefore, known as fat-soluble. They are not easily lost by ordinary cooking methods and they can be stored in the body to some extent, mostly in the liver. They are measured in international units. Vitamin B Complex and C are water-soluble. They are dissolved easily in the cooking water. A portion of these vitamins may be destroyed by heating.

They cannot be stored in the body and hence they have to be taken daily in foods. Any extra quantity taken in any one day is eliminated as waste. Their values are given in milligrams and micrograms, whichever is appropriate.

Vitamins, used therapeutically, can be of immense help in fighting disease and speeding recovery. They can be used in two ways, namely, correcting deficiencies and treating disease in place of drugs. The latest researches indicate that many vitamins taken in large doses far above the actual nutritional needs can have a miraculous healing effect on a wide range of common complaints and illnesses.

Vitamin therapy has a distinct advantage over drug therapy. While drugs are always toxic and have many undesirable side effects, vitamins, as a rule, are non-toxic and safe.

The various functions of common vitamins, their deficiency symptoms, natural sources, daily requirements, and their therapeutic uses are discussed in brief as follows :

Vitamin A

Known as anti-ophthalmic, vitamin A is essential for growth and vitality. It builds up resistance to respiratory and other infections and works mainly on the eyes, lungs, stomach, and intestines. It prevents eye diseases and plays a vital role in nourishing the skin and hair. It helps to prevent premature aging and senility, increases life expectancy, and extends youthfulness.

The main sources of this vitamin are fish liver oil, liver, whole milk, curds, pure ghee, butter, cheese, cream and egg yolk, green leafy and certain yellow root vegetables such as spinach, lettuce, turnip, beets, carrot, cabbage and tomato and ripe fruits such as prunes, mangoes, papaya, apricots, peaches, almonds, and other dry fruits. A prolonged deficiency of vitamin A may result in inflammation of the eyes, poor vision frequent colds, night blindness and increased susceptibility to infections, lack of appetite and vigor, defective teeth and gums, and skin disorders.

The recommended daily allowance of vitamin A is 5,000 international units for adults and 2,600 to 4,000 international units for children. When taken in large therapeutic doses, which are usually 25,000 to 50,000 units a day, it is highly beneficial in the treatment of head and chest colds, sinus trouble, influenza, and other infectious diseases. It is also valuable in curing night blindness and other eye diseases as well as many stubborn skin disorders. This vitamin can be given up to 1,00,000 units a day for a limited period of four weeks under a doctor’s supervision.

In a recent year-long study, huge doses of vitamin A given twice a year reduced death by about 30 percent among Indonesian children. This has raised hope in the fight against a significant cause of childhood mortality in developing countries.

B Complex Vitamins

There are a large variety of vitamins in the B group, the more important being B1 or thiamine, B2 or riboflavin, B3 or niacin or nicotinic acid, B6 or pyridoxine, B9 or folic acid, B12, and B5 or pantothenic acid. B vitamins are synergistic. They are more potent together than when used separately.


Known as an anti-beriberi, anti-neuritic, and anti-aging vitamin, thiamine plays an important role in the normal functioning of the nervous system, the regulation of carbohydrates, and good digestion. It protects heart muscle, stimulates brain action, and helps prevent constipation. It has a mild diuretic effect. Valuable sources of this vitamin are wheat germ, yeast, the outer layer of whole grains, cereals, pulses, nuts, peas, legumes, dark green leafy vegetables, milk, egg, banana, and apple.

The deficiency of thiamine can cause serious impairment of the digestive system and chronic constipation, loss of weight, diabetes, mental depression, nervous exhaustion, and weakness of the heart.

The recommended daily allowance for this vitamin is about two milligrams for adults and 1.2 mg. for children. The need for this vitamin increases during illness, stress, and surgery as well as during pregnancy and lactation. When taken in a large quantity, say up to 50 mg. , it is beneficial in the treatment of digestive disorders, neuritis, and other nervous troubles as well as mental depression.

For best results, all other vitamins of the B group should be administered simultaneously. Prolonged ingestion of large doses of any one of the isolated B complex vitamins may result in high urinary losses of other B vitamins and lead to deficiencies of these vitamins.


Vitamin B2 or riboflavin, also known as vitamin G, is essential for growth and general health as also as healthy eyes, skin, nails, and hair. It helps eliminate sore mouth, lips, and tongue. It also functions with other substances to metabolize carbohydrates, fats, and protein. The main sources of this vitamin are green leafy vegetables, milk, cheese, wheat germ, egg, almonds, sunflower, seeds, citrus fruits, and tomatoes. Its deficiency can cause a burning sensation in the legs, lips, and tongue, oily skin, premature wrinkles on the face and arm, and eczema.

The recommended daily allowance for this vitamin is 1.6 to 2.6 mg. for adults and 0.6 to one mg for children. Its use in larger quantities say from 25 to 50 mg. is beneficial in the treatment of nutritional cataracts and other eye ailments, digestive disturbances, nervous depression, general debility, and certain types of high blood pressure.


Vitamin B3 or niacin or nicotinic acid is essential for proper circulation, healthy functioning of the nervous system, and proper protein and carbohydrate metabolism. It is essential for the synthesis of sex hormones, cortisone, thyroxin, and insulin.

It is contained in liver, fish, poultry, peanut, whole wheat, green leafy vegetables, dates, figs, prunes, and tomatoes. A deficiency can lead to skin eruptions, frequent stools, mental depression, insomnia, chronic headaches, digestive disorders, and anemia.

The recommended daily allowance is 12 to 20 mg. for adults and 4.8 to 12 mg. for children. Large doses of this vitamin say up to 100 mg. with each meal, preferably together with other B group vitamins, affords relief in case of migraine and high blood pressure caused by nervousness, high cholesterol, and arteriosclerosis.


Vitamin B 6 or pyridoxine is a group of substances – pyridoxine, pyridoxal, and pyridoxamine – that are closely related and function together. It helps in the absorption of fats and proteins, prevents nervous and skin disorders, and protects against degenerative diseases.

The main sources of this vitamin are yeast, wheat, bran, wheat germ, pulses, cereals, banana, walnuts, soybeans, milk, egg, liver, meat, and fresh vegetables. Deficiency can lead to dermatitis, conjunctivitis, anemia, depression, skin disorders, nervousness, insomnia, migraine headaches, and heart diseases.

The recommended daily requirement is 2.0 mg. for adults and 0.2 mg. for children. This vitamin used therapeutically from 100 to 150 mg. daily can relieve painful joints and the discomforts of pregnancy and pre-menstrual symptoms. Vitamin B6 is now the most intensively studied of all vitamins.

Researches are on the threshold of several promising developments involving treatments of various ailments with this vitamin. They include hyperactivity in children, asthma, arthritis, kidney stones, blood clots in heart attack victims, and nervous disorders.

Folic Acid

Vitamin B9 or folic acid, along with vitamin B12 is necessary for the formation of red blood cells. It is essential for the growth and division of all body cells for healing processes. It aids protein metabolism and helps prevent premature greying.

Valuable sources of this vitamin are deep green leafy vegetables such as spinach, lettuce, brewer’s yeast, mushrooms, nuts, peanuts, and liver. A deficiency can result in certain types of anemia, serious skin disorders, loss of hair, impaired circulation, fatigue, and mental depression.

The minimum daily requirement of this vitamin is 0.4 mg. To correct anemia and deficiencies 5 mg or more are needed daily. Some authorities believe that folic acid is contraindicated in leukemia and cancer.

Pantothenic Acid

Vitamin B5 or pantothenic acid helps in cell building, main- training normal growth and development of the central nervous system. It stimulates the adrenal glands and increases the production of cortisone and other adrenal hormones. It is essential for the conversion of fat and sugar to energy.

It also helps guard against most physical and mental stresses and toxins and increases vitality. The main sources of this vitamin are whole grain bread and cereals, green vegetables, peas, beans, peanuts, and egg yolk. It can be synthesized in the body by intestinal bacteria. A deficiency can cause chronic fatigue, hypoglycemia, greying and loss of hair, mental depression, stomach disorders, and blood and skin disorders.

The minimum daily requirement of this vitamin has not been established but is estimated to be between 30 and 50 mg a day. The usual therapeutic doses are 50 to 200 mg. In some studies, 1,000 mg or more were given daily for six months without side effects. It is useful in the treatment of insomnia, low blood pressure, and hypoglycemia or low blood sugar.

Vitamin B12

Vitamin B12 or cobalamin, commonly known as “red vitamin”, is the only vitamin that contains essential mineral elements. It is essential for the proper functioning of the central nervous system, production, and regeneration of red blood cells, and proper utilization of fat, carbohydrates, and protein for bodybuilding.

It also improves concentration, memory, and balance. Valuable sources of this vitamin are kidney, liver, meat, milk, eggs, bananas, and peanuts. Its deficiency can lead to certain types of anemia, poor appetite and loss of energy, and mental disorders.

The recommended daily allowance of this vitamin is 3 mcg. Taken in large therapeutic doses from 50 to 100 mcg., it is beneficial in the treatment of lack of concentration, fatigue, depression, insomnia, and poor memory.

Vitamin C

Vitamin C or ascorbic acid is essential for normal growth and the maintenance of practically all body tissues, especially those of the joints, bones, teeth, and gums. It protects one against infections and acts as a harmless antibiotic. It promotes healing and serves as protection against all forms of stress and harmful effects of toxic chemicals. It helps prevent and cure a common cold. It also helps in decreasing blood cholesterol.

This vitamin is found in citrus fruits, berries, green and leafy vegetables, tomatoes, potatoes, sprouted Bengal, and green grams, A deficiency can cause scurvy marked by weakness, anemia, bleeding gums and painful and swollen parts, slow healing of sores and wounds, premature aging and lowered resistance to all infections.

The recommended daily allowance is 50 to 75 mg. for adults and 30 to 50 mg. for children. Smokers and older persons have a greater need for vitamin C. It is used therapeutically in huge doses from 100 to 10,000mg. a day. It prevents and cures colds and infections effectively, neutralizes various toxins in the system, speeds healing processes in virtually all cases of ill health increases sexual vitality, and prevents premature aging. According to Dr. Linus Pauling, a world-famous chemist and nutrition expert, ” because vitamin C is one of the least toxic vitamins, it is very safe to use in high doses. ” Your body will take exactly what it needs and excrete any excess naturally.”

Vitamin D

Vitamin D is necessary for proper bone and teeth formation and the healthy functioning of the thyroid gland. It assists in the assimilation of calcium, phosphorus, and other minerals from the digestive tract. This vitamin is found in the rays of the sun, fish, milk, eggs, butter, and sprouted seeds. A deficiency can cause gross deformation of bones and severe tooth decay.

The recommended daily allowance of this vitamin for both adults and children is 400 to 500 international units. Therapeutically, up to 4,000 to 5,000 units a day for adults, or half of this for children, is a safe dose if taken for not longer than one month. It is beneficial in the treatment of muscular fatigue, constipation, and nervousness. It can be toxic if taken in excessive doses, especially for children. Signs of toxicity are unusual thirst, sore eyes, itching skin, vomiting, diarrhea, urinary urgency, and abnormal calcium deposits in blood vessel walls, liver, lungs, kidneys, and stomach.

Vitamin E

Vitamin E is essential for normal reproductory functions, fertility, and physical vigor. It prevents unsaturated fatty acids, sex hormones, and fat-soluble vitamins from being destroyed in the body by oxygen. It dilutes blood vessels and improves circulation.

It is essential for the prevention of heart diseases, asthma, arthritis, and many other conditions. It is available in wheat or cereals germ, whole grain products, green leafy vegetables, milk, eggs, all whole, raw, or sprouted seeds and nuts. Its deficiency can lead to sterility in men and repeated abortions in women, degenerative developments in the coronary system, strokes, and heart disease.

The official estimated requirement of this vitamin is 15 international units. Expert nutritionists estimate the actual requirement at 100 to 200 I.U. a day.

The therapeutic doses are from 200 to 2400 I.U. daily. It is beneficial in the treatment of various forms of paralysis, diseases of the muscles, and arteriosclerotic heart disease by dilating blood vessels. It prevents the formation of scars in burns and post-operation healing. It protects against many environmental poisons in the air, water, and food. It also has a dramatic effect on the reproductive organs and prevents miscarriage, increases male and female fertility, and helps to restore male potency.

Vitamin K

Vitamin K is necessary for the proper clotting of blood, prevention of bleeding, and normal liver functions. It aids in reducing excessive menstrual flow. This vitamin is contained in egg yolk, cow’s milk, yogurt, alfalfa, green and leafy vegetables, spinach, cauliflower, cabbage, and tomato. Its deficiency can lead to sufficient bile salts in the intestines, colitis, lowered vitality, and premature aging.