Vitamins | Types of Vitamins | Source & Functions

In this article, we will know about Vitamins, types of vitamins such as Fat-soluble and water-soluble vitamins, Vitamin A, D, E, and K. We will also know role and functions, sources, daily recommended requirement, and deficiency. 

What are Vitamins?

Vitamins are micronutrients which are essential in small amounts for normal body function such as maintenance, growth, development, and production. Most of the vitamins are made by plants with the help of sunlight. They are organic compounds distinct from proteins, carbohydrates, and fats. They act as biological regulators and metabolic regulators. Vitamins cannot be synthesized in the body except vitamin D and vitamin K which can be synthesized in the body. There are about 30 different types of vitamins described so far.
Vitamins, Types of Vitamins, Source, Role, and Functions,

Types of Vitamins

Vitamins are generally divided into two groups:
1. Fat-soluble vitamins: There are four types of fat-soluble vitamins such as A, D, E, and K. These vitamins are stored in fatty tissues and liver for long period of time because you do not need them every day and the body can use these vitamins stores for future use. They do not dissolve in water but dissolve in fat. If these are taken in excess, they cause a condition of toxicity and adverse reaction. Each of the fat-soluble vitamins has multiple functions in the body.

2. Water-soluble vitamins: The water-soluble vitamins are B1(thiamin), B2(riboflavin), B3(niacin), B5(pantothenic acid), B6(pyridoxine), B12(cyanocobalamin), C(ascorbic acid), biotin, and folic acid. These vitamins are easily absorbed directly into the bloodstream. Once absorbed, they circulate in the body and are available when needed for body function.
Most of the water-soluble vitamins are not stored in the large amounts for a long period of time. If water-soluble vitamins are the excess amount in the body, they have washed away from the body via urine.
Let's discuss first fat-soluble vitamin one by one in detail.

Vitamin A (Retinol)

What Is Vitamin A?
➲ Vitamin A, also called retinol, was discovered by Mc Collum and Davis but was isolated by Holmes. It is also known as an anti-infection
➲ Vitamin-A can be found in fruits, vegetables, eggs, milk, butter, meat, and fish. 
➲ It can be synthesized in the liver from yellow and red carotenoid pigments.
➲ It forms the retinal pigments such as rhodopsin of rod cells and codopsin of cone cells of the retina.
➲ It is required for normal growth of children.

Role and functions of Vitamin A

Each vitamin has some specific function. Some are used more widely than others and are needed in large amounts. The specific function and role of vitamin A are given below.

1. Vitamin A is required for the maintenance of normal night vision.
2. It helps in maintaining the healthy immune system.
3. It also helps in repairing and growing the skin, hair, nail, cornea of the eye.
4. Vitamin A is involved in the development of sperm and organs.
5. It also involves in the formation and maintenance of the teeth, bones, tissues, white blood cells, and the immune system. 
6. It maintains normal, living secretory epithelia in mucous membranes and glands.

Source of Vitamin A

Sources of vitamin A are Chicken liver, fish oil, cheese, milk, egg yolk, carrot juice, green vegetables, Ghee, butter, tomatoes, papaya, guava, orange, sweet potato, mango etc.

Recommended Daily intake

The recommended daily requirement of vitamin A is 900 micrograms(mcg) for adult men, 700 mcg for women, 770 mcg for during pregnancy, and 1300 mcg during breastfeeding. 

Vitamin A Deficiency

Deficiency of vitamin A cause diseases like Night blindness, Dry eyes(Xerophthalmia), Dry and itchy skin, and Diarrhea.

Vitamin D(Calciferol)

➲ It is also known as a sunshine vitamin or antiricket vitamin.
➲ It is an essential nutrient which you can get in the body when your skin is exposed to the sunlight for a certain period of time. otherwise, you will have to take an essential amount from the foods. 
➲ It has two major forms vitamin D2 and vitamin D3.
➲ Vitamin D is synthesized in the skin by cholesterol and UV light.
➲ It regulates absorption and utilization of calcium and phosphorus.

Role and Functions of vitamin D

1. Vitamin D regulates the calcium and phosphorus levels in the blood by promoting their absorption from food in the intestine, and by promoting re-absorption of calcium in the kidney.
2. It promotes bone formation and mineralization.
3. It is essential in the development of the strong skeleton.
4. It inhibits parathyroid hormone secretion from the parathyroid gland.
5. It also affects the immune system by promoting the immunosuppression and anti-tumor activity.
6. It helps in maintaining the muscles strength and normal glucose level.

Sources of vitamin D

Sources of vitamin D are meat, liver, milk, cod liver oil, and shark liver oil, fish, egg yolk, Mushroom etc.

Recommended Daily intake

The recommended daily requirement of vitamin D for adults between 19 to 50 years is 15 micrograms(mcg) per day,  for 71+ years 20 mcg per day, 15 mcg per day for during pregnancy, and breastfeeding woman. 

Vitamin D Deficiency

Deficiency of vitamin D cause diseases like poor mineralization of bones causing rickets in children, osteomalacia(soft bones), and if the calcium is also deficient in adults, osteoporosis may be.

Vitamin E(Tocopherols or Tocotrienol)

It is commonly called antisterility vitamin or beauty vitamin.
It inhibits peroxide formation and thereby prevents the damage of membrane lipids.

Role and Functions of vitamin E

1. Vitamin E removes scars and wrinkles of the skin.
2. It acts as an antioxidant in the human body. 

Sources of vitamin E

Sources of vitamin E are wheat, sunflower seeds, almonds, peanuts, vegetable oils, dark leafy vegetables, sweet potato, pumpkin, oily fish etc.

Recommended Daily intake

The recommended daily requirement of vitamin D for adults and a pregnant woman is 15 mg per day, and during breastfeeding woman, 19 mg per day.

Vitamin E Deficiency

Vitamin E deficiency diseases are sterility(impotent) and muscular atrophy.

Vitamin K(Phylloquinone)

➲ It is commonly called Anti hemorrhagic vitamin.
➲ It is synthesized by bacteria in the colon.
➲ It was discovered by Danish Scientist Dam in 1935.

Role and Functions of vitamin K

1. It is essential for the normal blood clotting.
2. It helps to increase the strength of bone.
3. It is essential for the synthesis of prothrombin in the liver.

Sources of vitamin K

Sources of vitamin K are green plants, green cabbage, cauliflower, spinach, nuts, fruits, vegetable oils etc.

Recommended Daily intake

The recommended daily requirement of vitamin K for adult men is 120 mcg per day and for a woman(during pregnancy and breastfeeding) is 90 mcg per day.

Vitamin K Deficiency

Deficiency of vitamin K causes uncontrolled bleeding(no coagulation or clotting).

Final words:
I hope that this article will give basic knowledge of Vitamins, Types of vitamins Fat-soluble and Water-soluble vitamins, source, role, and function and many more. We have covered almost all the important topic related to Fat-soluble vitamins.