As another season of colds and flu gets underway, many of us are looking for ways to bolster our immune systems, a critical step to fighting off the estimated two to four cold viruses that will afflict most Americans this year, as well as more serious diseases.
A healthy immune system produces fighter cells, killer cells and scavenger cells that search and destroy foreign invaders?microorganisms. But this highly complex defense arsenal depends on an adequate and steady supply of nutrients. EN reports the latest research.
B Sure. B vitamins are vital to cell reproduction, including cells involved in the body’s defenses. Even borderline deficiencies of vitamins B6, B12 and folic acid can wreak havoc with immune function. Older people are especially vulnerable, because they are more likely to be deficient in these particular vitamins. For insurance, take a multi.
C the Difference. Vitamin C is renowned for preventing colds, a reputation it doesn’t deserve; there’s little solid evidence for that. But it is a critical component of a healthy immune defense. EN recommends getting at least 200 milligrams a day, by eating plenty of citrus plus other fruits and vegetables.
Get E-nough. Not getting enough vitamin E can also derail the immune system. Look to wheat germ and almonds as super sources. The amount of E for optimal immunity may be as high as 200-800 International Units (134-536 milligrams) daily?levels available only with supplements. Such amounts have been shown to restore age-related declines in immune function.
A-void Too Much. Some nutrients?notably vitamin A?can backfire and actually suppress immune function if you get too much. Vitamin A is essential for a healthy immune system, but too much of the retinol form of A is detrimental to immunity, bones and liver. Look for a multi that provides no more than 100% of the Daily Value (DV) for vitamin A, with at least 20% as beta-carotene.
Critical Mineral Players. Several minerals key to a healthy immune system are plentiful in lean red meats, whole grains, nuts, beans and fortified cereals.
Zinc is crucial for normal immune cell development and growth. Particularly vulnerable to a zinc deficiency are cells that replenish rapidly, such as those in the outer layer of skin and in the lining of the gastrointestinal and respiratory tracts. Even borderline deficiencies of zinc leave older people vulnerable to attack by opportunistic infections. But stick to 100% of the DV in your multi; too much actually impairs immunity.
Copper deficiency can reduce acquired immunity. When under attack, a copper-poor body is less able to produce T cells, B cells and antibodies?immune-specific cells that help activate a cascade of events to kill off invaders. Copper deficiency also causes a decline in circulating neutrophils, white blood cells that ingest invaders. Choose a multi with copper.
Iron is also essential for keeping immunity strong, but too much can be as detrimental as too little, because extra iron fuels invading organisms. Men and postmenopausal women do not need extra iron, unless anemic. Otherwise, choose a multi without iron.
Selenium also aids immune function, but supplements are not recommended; it’s too easy to get too much. Brazil nuts are super-high; limit to two daily.
Focus on Favorable Fats. High blood cholesterol is not only bad for your heart, but may also impair immunity. Researchers at the Human Nutrition Research Center on Aging at Tufts University in Boston compared immune function in people eating a high-fat diet (38% of calories) versus a low-fat diet (28% of calories). The low-fat diet enhanced T-cell-mediated immunity in older people with elevated low-density lipoprotein (LDL-cholesterol) levels.
Skimping on the right fats can be just as harmful. Your body needs alpha-linolenic acid, an essential omega-3 fatty acid in flaxseed, walnuts and canola oil, and a precursor to the more potent omega-3 fats in fish. Also essential is linoleic acid, an omega-6 fatty acid in vegetable oils, margarines, nuts and seeds. Not getting enough of these fats can delay wound healing.
Shed Some Weight. Carrying around extra pounds can weigh down your immune system. Population studies show that the severity of some infectious illnesses are higher in obese people than in those who are lean. Researchers at the University of Navarra in Pamplona, Spain speculate that a link between an obesity hormone, leptin, and T-cell function is responsible for a poor antibody response in overweight people.
Overall Nutrition and Lifestyle. Getting older takes its toll on immunity; age-related changes make the body less able to fight off infection. Older people are particularly likely to be deficient in their intake of protein, calories, zinc and vitamin B6, making them especially vulnerable to disease.
Letting yourself get ?run-down? is a catchall phrase that includes skimping on sleep, poor nutrition and failing to effectively deal with stress. It may sound like common sense, but there’s science behind the following advice:
Get Moving. Moderate exercise boosts your immunity with each session. Research shows that over time this translates to fewer days of illness.
Look on the Bright Side. People who see the cup as half-full have healthier immune systems than those who see the cup as half-empty.
Get Your Zzzz’s. Shortchanging your body on sleep can shortchange your ability to make natural killer cells.
The Bottom Line. Besides the above lifestyle advice, give yourself the best chance to fend off unwanted illnesses:
? Eat a wide variety of foods. Include five to nine servings of fruits and vegetables daily, plus whole grains, lean protein, nonfat dairy foods and small amounts of nuts and seeds.
? Keep fat intake below 30% of calories. Choose immune-boosting fats found in olive and canola oils over butter, margarine or other oils.
? Megadoses of single nutrients?except perhaps vitamin E?are not likely to help. A general multivitamin/mineral formula is a safe, EN-recommended immune insurance policy.