Substances that strengthen the body and increase its resistance to disease?

The substances that strengthen the body include vitamins. Lack of vitamins in the human body leads to a weakening of its immunity. In total, there are 13 vitamins necessary for normal life. If vitamins are not enough. then a person begins vitamin deficiency, which leads to the destruction of the body. The first signs of vitamin deficiency are dryness of the skin, they can crack, hair falls out, nails and teeth deteriorate.
But. and an excess of vitamins has a negative effect on a person. Therefore, the rate cannot be exceeded.