As we all know, vitamins are essential nutrients to maintain the normal physiological functions of human body. They play an important role in the growth, metabolism, and development process of human body. There are various kinds of vitamins, each with its specific effect on human body. As a result, in the following passage, we will introduce them in detail.

1. :
Vitamin A can maintain the health of the skin and hair. If the body lacks of vitamin A, the skin will become dry and colorless. More seriously, it may lead to hair loss and other symptoms. Foods such as carrot, tomato, persimmon, peach, pumpkin, sweet potato and broccoli, are rich in vitamin A.

2. Vitamin B1:
The physiological function of vitamin B1 is to increase the appetite and maintain the normal activities of nerves. Lack of vitamin B1 will cause beriberi, neurodermatitis and so on. An adult needs to take in 2 mg of vitamin B1 every day. It is widely present in rice bran, egg yolk, cow milk, tomato and other foods.

3. Vitamin B2:
Vitamin B2 is also known as riboflavin. Without enough vitamin B2, the body will be susceptible to stomatitis, dermatitis, and so on. An adult should take in 2 to 4 mg of vitamin B2 every day. It is widely contained in foods such as grains, vegetables, milk, fish and so on.

4. Vitamin B3:
Vitamin B3 is also known as nicotinic acid. It not only can maintain the health of digestive system, but is also an indispensable material for the synthesis of hormone. For the modern people who live under great pressure, nicotinic acid can also help them maintain the health of nervous system and keep the normal operation of brain function.

5. Vitamin C:
Vitamin C is not only a powerful antioxidant, but is also an important nutrient for the production of collagen fibers. As a result, vitamin C has a good effect for skin-care. It can make the skin white, delicate, and elastic. At the same time, it can also reduce the risk of cancer and heart. Foods which contain plenty of vitamin C include kiwi fruit, papaya, broccoli, citrus, and so on.

6. :
The physiological function of vitamin D is to help the body absorb phosphorus and calcium. It is an essential raw material for the growth of bone. As a result, lack of vitamin D will lead to rickets. Foods such as cod liver oil, animal liver, egg yolk, are rich in vitamin D.