Is it better to take more vitamin supplements? Warning: Excessive intake may increase the risk of disease

Vitamins are a class of organic compounds necessary for maintaining normal life activities of the human body. They can be divided into fat-soluble vitamins and water-soluble vitamins. There are so many types of vitamins. What effects do they have on our immunity? Is it better to take more vitamins?

There’s a myth that the human body doesn’t need many vitamins every day, but it never hurts to get as much as possible.

The truth is that some types of vitamin supplements can cause toxicity when taken in excess of the standard amount. Among them, excessive intake of vitamin A and vitamin D may have the greatest toxic potential, niacin (vitamin B3) has moderate toxic potential, and the others have low or negligible toxic potential.

In addition, some vitamins can reduce the efficacy of certain drugs and even increase the risk of certain diseases. For example, the most common vitamin E has a good antioxidant effect and is often added to skin care products. It can also promote the secretion of sex hormones by taking vitamin E. However, excessive supplementation of vitamin E can increase the risk of heart failure by 13%.

Generally speaking, most diets provide a variety of vitamins that can meet the body's required levels and prevent clinical symptoms caused by vitamin deficiency. Vitamin supplements should only be considered in the following situations: women during pregnancy, gestation, and lactation should take appropriate folic acid supplements; vegetarians and people over 50 years old can take vitamin B12 supplements; newborns can take a single dose of vitamin K to prevent abnormal bleeding; certain drugs or diseases can interfere with the body's absorption or utilization of vitamins, in which case specific vitamins need to be supplemented.

Fat-soluble vitamins

Vitamin A

Vitamin A can promote the synthesis of immunoglobulins and improve the body's ability to resist infection and tumors; it can also eliminate immune tolerance. Various cytokines that affect immune responses may also change when vitamin A is deficient, thereby affecting the antigen-antibody response in the body.

Vitamin A is mostly found in animal foods, such as animal liver, fish eggs, whole milk, poultry eggs, etc.; in addition, carotenoids in plant foods can be converted into vitamin A, which is mainly found in dark green or red, orange and yellow vegetables or fruits, such as broccoli, spinach, water spinach, mango, apricots, persimmons, etc.

Vitamin D

Vitamin D is an important immunomodulator, and most cells in the body, including immune cells, contain vitamin D receptors. Vitamin D in macrophages can regulate the synthesis of endogenous cathepsin inhibitors and regulate the pattern of cytokine secretion; both cathepsin inhibitors and cytokines can enhance the body's defense against pathogens. People who are deficient in vitamin D are more likely to have respiratory infections, which are more frequent and more severe.

Human vitamin D is mainly synthesized by the skin through ultraviolet radiation or obtained from the diet. Vitamin D in food is mostly found in high-fat marine fish, animal liver, egg yolk and cream.

Vitamin E

Vitamin E is important for maintaining normal immune function, especially the function of T lymphocytes: it can enhance the stimulation reactivity of lymphocytes to mitogens and the response to antigens and antibodies, and promote phagocytosis; studies have shown that vitamin E can further affect immune function by affecting nucleic acid and protein metabolism.

The main source of vitamin E in the daily diet is vegetable oil. In addition, barley, oat and rice bran, as well as nuts are also good sources of vitamin E.

Water-soluble vitamins

Vitamin B6

Vitamin B6 promotes the synthesis of antibodies in the body, and is beneficial to the synthesis of nucleic acids and proteins as well as cell proliferation. When vitamin B6 is deficient, the synthesis of antibodies decreases, the body's resistance decreases, and the synthesis of DNA is impaired. Therefore, vitamin B6 is very important for maintaining proper immune function.

Vitamin B6 is widely available in food sources, including animal and plant foods, such as chicken, fish, animal liver, whole grain products, nuts, and egg yolks. Vitamin B6 is also found in high levels in vegetables and fruits, such as bananas, cabbage, and spinach.

Vitamin C

Vitamin C has an antioxidant effect, which can protect immune cells from oxidative damage and promote antibody formation. Vitamin C can regulate the function of phagocytes, the proliferation of T lymphocytes, the production of cytokines and the gene expression of monocyte adhesion molecules. In addition, vitamin C can prevent and delay the oxidation of vitamin A and vitamin E.

Vitamin C mainly comes from food, and fresh vegetables and fruits contain the most, such as chrysanthemum, cabbage, spinach, red dates, strawberries, citrus, etc. If you can regularly consume abundant fresh vegetables and fruits and cook them properly, you can generally meet the needs of the human body. (Compiled from the official website of Beijing Association for Science and Technology and China Center for Disease Control and Prevention)