Vitamins are a class of organic compounds necessary for human life activities and play a vital role in all stages of the immune response. Vitamins exist in natural foods, and the human body generally cannot synthesize them. They must be supplied by food. They can be divided into fat-soluble (vitamin A, D, E, K) and water-soluble (B vitamins, vitamin C).
Vitamin A-the “guardian” of the first defense line of immunity
Vitamin A is a general term for a class of compounds containing bioactivity of retinol. It has functions of maintaining normal vision, promoting proliferation and differentiation of epithelial tissues, and promoting growth and development of children. It participates in the whole process of the maturation of the human immune system, can improve the stability of the cell membrane, maintain the integrity of the mucosal barrier, and is the “guardian” of the first defense line of immunity.
The recommended intake of vitamin A for adults in my country is 800 μg RAE/d for men and 700 μg RAE/d for women. In daily life, the most vitamin A-containing food we can come into contact with is liver, and eggs are also rich in vitamin A. A healthy adult can consume pork liver 1 to 2 times a month, about 1 to 2 or so each time, to easily meet the needs of vitamin A. Carotenoids contained in vegetables and fruits can be converted into vitamin A in the body, especially dark green and red-yellow vegetables, such as broccoli, carrots, spinach, etc., contain more carotenoids, and can also supplement vitamin A. effect.
B vitamins-“help” the normal functioning of the immune system
B vitamins are a “big family”, including vitamins B1, B2, B6, B12, niacin, pantothenic acid, folic acid and so on. B vitamins are important coenzymes involved in the metabolism of the body’s three major nutrients, and are essential water-soluble vitamins to maintain the body’s normal function. B vitamins can mediate immune regulation and assist the normal operation of the immune system. For example, vitamin B6 participates in the proliferation, differentiation, maturation and activation of lymphocytes, regulates the production of cytokines and chemokines; vitamin B12 acts as an immune regulator of cellular immunity ; Folic acid supports immune response, etc.
Vitamins B1 and B6 are abundant in meat, vegetables, grains, and beans. Vitamin B2 is widely distributed in food, and the content in animal food is relatively high, especially liver, kidney, eggs, milk and so on. The vast majority of vitamin B12 comes from meat, such as fish, animal offal, eggs, milk and so on.
Vitamin C-the “number one helper” to enhance immune function
Vitamin C has various effects such as promoting collagen synthesis, promoting wound healing, and whitening skin. It supports immune defense by supporting various cell functions in non-specific immunity and specific immune response.
The recommended intake of vitamin C for Chinese adult residents is 100 mg/d. The main food sources of vitamin C are fresh vegetables and fruits, such as broccoli, peppers, cabbage and prickly pears, kiwi, strawberries, etc. A pound of vegetables and half a catty of fruit per day is enough to provide daily vitamin C, and the general population does not need extra supplement.
It should be noted that supplementing vitamin C through the daily diet is to eat fresh vegetables and fruits, because the vitamin C content will be greatly reduced after a long time. In addition, Vitamin C is easily decomposed by high temperature. For vegetables, eat them raw. It is recommended not to over-cook. Vegetable soup cooked with healthy fats will leave a lot of vitamin C. Drinking can not only supplement vitamin C, but also supplement high-quality fat.
Vitamin D-Regulator of immunity
In the last century, researchers proved through experiments that vitamin D is the ingredient in cod liver oil to treat rickets. Because it is the fourth named vitamin, it is called vitamin D.
Vitamin D is also called anti-rickets vitamin. Its main function is to regulate calcium and phosphorus metabolism, promote intestinal calcium and phosphorus absorption and bone calcification, and maintain blood calcium and blood phosphorus balance. Rickets, rickets, and osteoporosis occur when the body lacks vitamin D. Vitamin D receptors are widely present in immune cells, so they can participate in the proliferation and differentiation of various immune cells. In addition, vitamin D can not only enhance the innate immune response, but also suppress the acquired immune system, thereby regulating the immune response.
The recommended intake of vitamin D for Chinese adult residents is 10 μg/d. Vitamin D is rich in animal foods, such as liver, eggs, dairy products, etc. Among them, fatty fish is a good source of vitamin D. Sunlight is also the most important, natural and economical source of vitamin D, so vitamin D is called “sunshine vitamin”.
Vitamin E-the first line of defense against lipid peroxidation
Vitamin E can protect the integrity of cells and internal structures of cells and prevent the destruction of certain enzymes and internal components of cells. In addition, it can also enhance the secretion of luteinizing hormone and promote the completion of fertilization, which is also the origin of its tocopherol. Vitamin E (tocopherol) is an important fat-soluble antioxidant in cell tissues. It is the body’s first line of defense against lipid peroxidation, thereby protecting cell membranes from the damage of free radicals, and is important for maintaining the normal function of immune cells. .
The appropriate intake of vitamin E for Chinese adult residents is 14mg α-TE/d. Foods rich in vitamin E are widely distributed, and edible oil is usually the main source of vitamin E intake from the diet. In addition, beans, nuts and vegetables all contain a certain amount of vitamin E.
Vitamins are essential for maintaining the normal immune function of the human body. A healthy and balanced daily diet can provide various vitamins required by the human body, thus casting an indestructible line of defense for the body!