We’re at the start of winter cold and flu season, and inside your body, a series of small battles is being waged. The army, your immune system, is made up of a number of key players, all dedicated to protecting you from foreign invaders. How to keep immunity healthy and balanced? In part one, we’ll show you the best advice on what to eat and what to avoid. Stay tuned for part two, on what to take and how to live.
What to eat.
The immune system is like an army protecting the body from foreign invaders, and it’s important to keep the soldiers well nourished. But studies of supplementing with individual nutrients are mixed, and mega-doses of certain vitamins can adversely impact immunity. The best defense is a balanced diet, with ample amounts of certain key nutrients. Some of the most important:
Brazil nuts. They’re high in selenium, a powerful antioxidant that has been shown in a number of studies to significantly improve immune response.1 Other good sources of selenium include halibut, turkey and sardines. Easy fixes: chop Brazil nuts and add to steamed quinoa; puree Brazil nuts, garlic, fresh basil and olive oil for pesto.
Pumpkin is rich in vitamin A, which enhances immune functions, such as white blood cell activity. Vitamin A also has antioxidant properties, and studies have shown that a deficiency increases risk of infectious disease.2 Carrots, sweet potatoes, spinach, collards and kale are also high in vitamin A. Easy fixes: add pureed pumpkin to pasta sauce, halve sugar pie pumpkins and roast until tender.
Oysters are the richest source of zinc, an antioxidant mineral that’s essential for immune cell function.3 Many studies have shown that even mild zinc deficiency depresses immunity.4 Beef, crab, turkey and kidney beans are other good sources of zinc. Easy fixes: add oysters to stuffing recipes; combine oysters, crab and fish in a fragrant stew.
Red peppers contain vitamin B6, which is necessary for production of several important immune system cells.5 Other good B-6 sources: tuna, spinach, cod, bananas, soy and beans. Easy fixes: puree roasted red peppers and white beans for a quick dip; add minced red peppers to tuna salad.
Papayas are rich in vitamin C, long recognized for its immune-enhancing effects. Studies have shown that vitamin C improves many components of the immune system, including natural killer cell activities. Strawberries, grapefruit juice, peaches, peppers, broccoli and Brussels sprouts are other good sources. Easy fixes: add frozen papaya cubes to smoothies; combine chopped papayas and peaches with minced jalapenos, red onion and lime juice for salsa.
Sunflower seeds are rich in vitamin E, essential for overall immune function; in studies, even a small vitamin E deficiency impaired immune response. 6 Other good sources of vitamin E: almonds, turnip greens, spinach and beet greens are other good sources. Easy fixes: puree sunflower seeds with cooked artichokes, swap sunflower butter for peanut butter on sandwiches.
What to avoid.
Some foods, toxins and drugs upset immune system balance and deplete the body’s ability to ward off toxins. The worst offenders:
Sugar decreases the ability of white blood cells to engulf bacteria—in some studies, as much as 40 percent. White sugar is the worst, but any concentrated sweetener—including honey, agave and maple syrup—has similar actions. Same with pasta, bread, baked goods and other refined carbohydrates that lack adequate fiber to slow the release of glucose into the bloodstream. Stick to low-glycemic carbs, like sweet potatoes, quinoa, oat groats, buckwheat and beans, and use sugar in great moderation.
Coffee and other significant sources of caffeine tax the adrenal glands and central nervous system, increasing stress—which directly impacts immune function. Keep your coffee intake to one cup a day; or combine coffee grounds with Teecino ground herbal coffee substitute, and brew as usual. At coffee shops, stick to decaf coffee, chai or green tea.
Alcohol. Drinking wine, beer and hard liquor hamper immunity in much the same way as sugar: by reducing the ability of white blood cells to fight pathogens. Excessive alcohol intake—three drinks or more– also inhibits the ability of white blood cells to protect against cancer. Additionally, heavy drinking usually results in deficiencies of key immune-boosting nutrients. Stick to one drink a day, or less; if you’re drinking red wine for the health benefits, switch to red grape juice to get the same heart-healthy antioxidants (mainly resveratrol).
Allergenic foods. Food allergies, or even sensitivities, stress the immune system; the most common offenders are gluten, dairy, corn, soy and peanuts. Food additives, like artificial colors, preservatives and pesticide residues, may also cause sensitivities. Focus on whole, unprocessed foods (those without a label); if you suspect that you’re allergic to a food, work with a nutritionist to identify offending foods.
Obesity. Some studies suggest that excessive amounts of stored fat in the body trigger inflammation and upset the immune system; one theory is that some fatty acids “look” like bacterial invaders, leading the body to believe they’re foreign invaders. Additionally, obesity can lead to resistance to leptin–a hormone produced by fat cells that supports white blood cell production and enhances immune function.
Next up: Infection Protection, part 2—what to take, how to live