Vitamins are a big family. There are dozens of known vitamins, which can be roughly divided into two categories: fat-soluble and water-soluble. Some substances that are similar in chemical structure to a certain vitamin and can be converted into vitamins through simple metabolic reactions are called provitamins. For example, beta-carotene can be converted into vitamin A.
Vitamins Absorbability
Water-soluble vitamins, after being absorbed from the intestinal tract, are circulated to the tissues required by the body, most of which are excreted in the urine, and very little is stored in the body. Fat-soluble vitamins are mostly absorbed by bile salts and circulated to various organs of the body through the lymphatic system, and the body can store a large amount of fat-soluble vitamins. Vitamins A and D are mainly stored in the liver, vitamin E is mainly stored in adipose tissue, and vitamin K is stored to a lesser extent.
Fat-Soluble Vitamins
1. Vitamin A is not a single compound, but a series of derivatives of retinol, also known as anti-dry eye vitamin. It is rich in cod liver oil and green vegetables.
2. Vitamin D, also known as calciferol, anti-rickets vitamin, mainly includes vitamin D or ergocalciferol and vitamin D or cholecalciferol. This is the only vitamin that animals can synthesize in small amounts. It is rich in cod liver oil, egg yolks, dairy products, yeast.
3. There are four main types of vitamin E: alpha, beta, gamma, and delta. It is rich in eggs, liver, fish, vegetable oils.
4. Vitamin K is a general term for naphthoquinone derivatives, mainly including natural vitamin K1 from plants, vitamin K2 from animals, and synthetic vitamin K3 and vitamin K4, also known as coagulation vitamins. It is rich in spinach, cabbage, liver.
Water-Soluble Vitamins
1. Thiamine is normally present in the body in the form of thiamine pyrophosphate (TPP). It is mainly found in yeast, grains, liver, soybeans, meat.
2. Riboflavin, mainly found in yeast, liver, vegetables, eggs.
3. Niacin, also known as vitamin P and vitamin PP, includes niacin and niacinamide, both of which are pyridine derivatives.
4. Pantothenic acid, mainly found in yeast, grains, liver and vegetables.
5. Pyridoxines, including pyridoxine, pyridoxal, and pyridoxamine, are found in yeast, grains, liver, eggs, and dairy products.
6. Biotin, also known as vitamin H, is found in liver and grains.
7. Folic acid is mainly found in the leaves and liver of vegetables.
8. Choline is one of the B vitamins and is abundant in liver, egg yolks, dairy products and soy.
9. Vitamin C, also known as ascorbic acid, is found in fresh vegetables and fruits.