Your immune system is like a defensive army. If you don't keep it in tip-top shape, you increase its chances of succumbing to invaders. Getting a regular flu shot, washing your hands regularly and getting sufficient amounts of rest are a few ways you can build up your army. The foods you eat can significantly influence your health, so bulk up on immunity boosting nutrients.
Antioxidants
Antioxidants are substances that may help combat oxidation, according to the National Center for Complementary and Alternative Medicine. Oxidation, a chemical process that occurs in your body as you age, can produce unstable molecules called free radicals. These free radicals are produced during day-to-day functions such as food breakdown. Stress, alcohol consumption and exposure to substances such as cigarette smoke, alcohol, sunlight and environmental contaminants can also cause your body to produce free radicals. Excessive levels of free radicals are thought to boost your risk of developing diseases such as cancer and heart disease, but they can also interfere with your ability to fight off illnesses such as the common cold. Antioxidants derived from food include beta-carotene, selenium and vitamins C and E.
Fruits
Fruits high in antioxidants include berries, citrus fruits, cantaloupe, cherries, avocados, plums, mangoes, pineapple, kiwis, tomatoes and many varieties of apples. Berries, citrus fruits, citrus fruit juices and tomatoes are particularly high in vitamin C. Apricots, mangoes and cantaloupes are especially rich in beta-carotene. Most adults need between 1.5 and 2 cups of fruit per day. A single cup of fruit is equivalent to about 1 cup of 100 percent fruit juice or a half cup of dried fruit, but most of your daily fruit intake should be fresh.
Vegetables
Vegetables that are rich in antioxidants are generally vivid in color. Red and yellow peppers as well as green vegetables such as spinach, green peppers, broccoli and asparagus are high in vitamin C, according to the Cleveland Clinic. Vitamin E and beta-carotene are also present in dark leafy green vegetables such as kale, broccoli and spinach. You can also find beta-carotene in sweet potatoes, red and yellow peppers and carrots. Most adults need about 2 to 3 cups of vegetables per day. A single cup of vegetables equals about 1 cup of cooked or raw vegetables, 1 cup of vegetable juice or 2 cups of raw leafy greens.
Grains
Whole grains, wheat germ, oatmeal and brown rice are rich in vitamin E and selenium. However, oat-based products such as oatmeal are generally highest in antioxidants. Another immune-system boosting perk of oats is that they contain soluble fiber. Research at the University of Illinois found that soluble fiber helps heal cells that help speed up recovery from infection. Most adults need between 6 and 8 oz. of grains each day, but at least half of them should be whole grains. A 1 oz. serving of grains equals about one slice of bread or a half cup of cooked rice or cereal.
Proteins
Soybeans, nuts and nut butters are rich in vitamin E. Brazil nuts, dairy products, eggs, chicken and seafood are rich in selenium. Most adults need between 46 and 56 g of protein per day. One 8 oz. container of yogurt contains about 11 g of protein and 3 oz. of tuna contains about 22 g of protein. Because many protein foods are also rich in calories, limit your intake of oily foods, replace whole fat dairy products with low-fat or skim varieties and emphasize plant-based protein in your diet over animal-based protein.
References
- Linus Pauling Institute at Oregon State University: Vitamin C
- Women's Health: Improve Your Immune System with Food
- Harvard Health Publications: How to Boost Your Immune System
- Cleveland Clinic: Antioxidant Food Table
- Science Daily: Study Shows Soluble Fiber Boosts Immune System; March, 2010
- National Center for Complementary and Alternative Medicine: Antioxidant Supplements for Health; May, 2010
