William Booth Walter, a nutrition and immunity expert at Scripps Institute in California, said: "Low-nutrition diet is the biggest reason why healthy bodies weaken the immune system." And a comprehensive and healthy diet is the key to strengthen the immune system. The following foods can strengthen the immune system and keep your immune system in a fighting state. Beef: Strengthening Your Weaknesses Zinc deficiency is a phenomenon that most adults are undernourished, especially vegetarians and people who don't eat beef, because beef is an important source of immune minerals. If zinc is deficient, even a slight deficiency will increase the risk of infection. Buswater explained that zinc also plays an important role in the growth of white blood cells. These brave immune cells can identify and destroy invading bacteria and viruses, and can also classify other bad cells. About 86 grams of lean beef (good enough to make a roast beef sandwich) can provide 30% of the daily zinc demand. This has made a difference between zinc deficiency and zinc enrichment. Not only eat beef, but also try zinc-rich oysters, zinc-enriched grains, pork, poultry, yogurt or milk. Sweet potato: Consolidate your line of defense You may not think that skin is a part of your immune system. This important organ covering an area of about1.5 square meters is the first line of defense against the invasion of bacteria, viruses and other harmful substances. To get healthy skin, you need vitamin A. One of the ways to get vitamin A is to eat food containing beta carotene, which can be converted into vitamin A by human body. A quick, convenient and delicious way to get beta carotene is to eat candied sweet potatoes. Each half cup of candied sweet potato contains only 170 calories, but it can provide 40% of the daily requirement of beta carotene. This kind of food is so wonderful that you can use it as a dessert. Other foods rich in beta carotene are: carrots, pumpkins (canned), cantaloupes and cantaloupes. Mushrooms: accelerating the vitality of white blood cells. People all over the world have been eating mushrooms to enhance their immunity for centuries. Modern research reveals the reasons. Douglas, director of the Institute of Natural Medicine in Washington, D.C., said: "Studies show that mushrooms can increase the number of white blood cells, make them more energetic, and thus become more aggressive. This is undoubtedly a good thing for people to resist infection. " Now you can buy fresh mushrooms everywhere, and eating mushrooms often can greatly improve your immunity. Mushrooms are also very easy to eat, just add a little seasoning, sauce and a little cooking oil; You can also make pizza with eggs. It doesn't matter to people who are not good at cooking, because it can be said that mushrooms will greatly enhance and mobilize people's immune system as long as they are used for cooked food. Tea: antioxidant soup like all wars, the war with bacteria is also a melee. When people's immune system repels invading bacteria and viruses, and then begins to repair and rebuild the damage caused by them, some potentially destructive mixtures (called free radicals) will be produced. They can destroy cells and their DNA, accelerate aging and form the basis of diseases such as cancer. Antioxidants can clean up these free radicals before they take their toll. Fruits and vegetables contain antioxidants, but black tea and green tea obviously contain higher antioxidants than the above two. So drink a large glass of this "antioxidant soup". In recent research, bagged tea can release a lot of polyphenols, which is a strong antioxidant. Yogurt (Yogurt): The intestinal mucosa of the reinforcements is home to hundreds of millions of good bacteria, which resist the invading harmful bacteria through the intestinal wall. Unfortunately, antibiotics can destroy these good bacteria, making people vulnerable to the attack of those unwelcome and hateful bacteria that cause diarrhea. People can eat yogurt or strengthen their intestines with a delicious yogurt wine. This delicious food with a long civilization tradition is an excellent source of healthy bacteria, which can re-arm people's intestinal defense line. Ruth Dibak of the Digestive Disease Clinic said: "Early studies have confirmed that this exquisite food enhances the immune system's response, thus improving general health. This kind of food tastes delicate and smooth, and the calorie of a cup of yogurt (sour milk wine) is 160 calories, which is a favorite dessert. "