14 Vitamins and What they do in Our Body

Vitamins are the natural biomolecules that are present in the human body.

They are called catalysts because along with the enzymes, they speed up the biochemical reactions.

These vitamins are present in very minute quantities and can be had from nutritious food. But interestingly they have no calorific value.

Their deficiency for prolonged periods can lead to vitamin deficiency diseases.

Plants synthesize vitamins on their own.

But humans synthesize some, store some while the remaining have to be taken from the diet. So let’s go into more details on

Vitamins and What they do

Vitamins are organic substances that regulate the body’s physiology.

These vitamins are of two types based on their solubility as fat and water-soluble ones.

Vitamins and What they do

The fat-soluble ones include vitamin A, D, E, and K while the water-soluble ones include vitamin B and C.

The fat-soluble ones are stored in the body for a long period and do not need regular replenishment.

While the water-soluble ones are easily excreted from the body through water. Hence, they need regular replenishment into the body.

Further, these individual vitamins are available in different forms.

E.g. Vitamin D is available as Vitamin D2 and D3, Vitamin K as K1 and K2.

While water-soluble vitamin B is a complex one, it is comprised of 8 vitamins like B1, B2, B3,  B5, B6, B7, B9, B12.

These vitamins perform diverse functions in the body like

1. They are enhancers of various body reactions, i.e., they speed up the reactions.

2. They are involved in the synthesis of various substances in the body like fats, proteins, DNA, RNA.

3. They play a key role in the formation of body cell-like red blood cells (RBC),  WBC, etc.

4. They stimulate the formation of bone cells, cones (color sensors) in eyes, bone cells, etc.

5. Vitamins like Vit. C helps fight against cold and other infections.

6. They promote reproductive health. Ex Vit. E

More details on individual vitamins, their functions, and deficiency diseases can be seen in the table below.

Vitamins SourcesFunctions Deficiency Diseases
Vitamin-Aa) Carrot, tomato, mango
b) Milk, Ghee, Butter, Egg
c) Shark & Cod liver oils
Body growth, weight, vision, healthy eyes, skin & nervous system. Aid fertility, bone cell formationNight blindness, xeropthalmia, digestive disturbance, respiratory infections, irregular bone growth
Exposure to sunlight, fish liver oils, egg yolk, fortified foods
It promotes calcium absorption, bone mineralization, cell growth, glucose metabolism.Rickets, Osteomalacia, dental abnormalities, hypocalcemic seizures, and more.
Vitamin-Ea) Wheat sprout, Soyabean, edible oils.
b) Milk, butter & leafy vegetables.
As an antioxidant, involved in immune function, cell signalling and metabolism.Degeneration of muscles, nerves, retinopathy, immune deficiecny, chances of abortion.
Vitamin-KFound in green leafy vegetables like collard greens, spinach, soy, cheese, meat, gut bacteria, etc.It aids in the clotting of blood, the building of the bones.Bleeding tendency, osteoporosis
Vitamin-C (Ascorbic acid)Mainly available in plant sources like citrus fruits (lemons, oranges, grapes, gooseberries), Guava, potato, etc.It acts as an anti-oxidant, helps form blood vessels, cartilage, muscles, and store Iron. Scurvy is seen with bleeding gums, Petechiae, i.e., under skin bleeding as seen by small red patches.
Vitamin-B1 (Thiamine)Pulses, nuts, upper coats of cereals, carrots, beans, etc.Oxidation of sugars to produce energy, fat synthesis aids in the growth, functioning of the heart, nerves, musclesBeri-beri, muscular weakness.
Vitamin-B2 (Riboflavin)Green vegetables, milk, eggs, meat. Also by bacteria in the intestine.Body growth, cellular respiration, transfer of light stimuli in the eye, protein metabolismSwelling of lips, tongue, dry skin, hair fall, etc.
Vitamin-B3 (Niacin)Beans, Pulses, cereal coat, tomato, milk, fish, meat, etcAs a Co-enzyme in the oxidative process of energy generation, dilation of blood vesselsPellagra, macrocytic anemia
Vitamin-B5 (pantothenic acid)Peas, Sweet potato, liver, eggs, meatCarbohydrate metabolism to generate energy, fat, cholesterol synthesisFatigue, irritability, hypoglycemia, etc.
Vitamin-B6 (pyridoxin)Cereals, fish, eggs, by Bacteria in the gutSynthesizing fats, proteins, carbohydrates.Ulceration, conjunctivitis, glossitis, etc.
Vitamin-B7 (Biotin) (VItamin-H)Peas, cauliflower, liver
Cell growth, maintains steady glucose level in the blood, formation of fatty acids
hair loss, conjunctivitis, dermatitis.
Vitamin-B9 (Folic Acid)Soya bean, Leafy vegetables, milk, meatRBC formation, nucleic acid synthesis (DNA, RNA)Megaloblastic anemia.
Vitamin-B12Milk, Egg, meat, etc. Absent in plants.RBC formation, Enhances WBC & thrombocytes production, Good for the nervous system and lipid formation.Damage to brain, anemia

As seen above, vitamin deficiency causes diseases. This vitamin deficiency does not occur in individuals with a healthy lifestyle.

But it can frequently occur during pregnancy, lactation, Malnutrition. Even alcoholism and a few medications can also cause vitamin deficiency.

The best way to recover from the loss is through the consumption of foods rich in related vitamins.

And still, if there is a deficiency, then one can take up the vitamin supplements.

If you consider being suffering from any vitamin-related diseases, it is better to consult a physician.

Medical applications of vitamins:

Vitamins in a multi vitamin and mineral capsules

Besides their use in deficiency diseases, vitamins find their use in medicine.

1. Vitamin A is used in the treatment of pimples in the form of retinol from animals.

2. Vit. B is used in consumption diseases like tuberculosis treatment.

Vitamin-B6 is included along with treatment regimen drugs. Because Isoniazid, a TB drug cause causes peripheral neuropathy. With the addition of Vitamin B6, this adverse effect can be prevented in the patients.

Also, vitamin B is used as an appetite stimulant, i.e., it enhances hunger.

3. Vit. E is used during pregnancy and also to enhance conception. Hence, it is routinely employed even in animals breeding.

4. Vit. C and Vit. B combinations are used in case of ulcers in the mouth and gut.


  1. Vitamin C
  2. Vitamin D fact sheet for health professions.
  3. Vitamin K.
  4. Vitamin E Deficiency

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