It’s that time of year again. Perhaps you’re already fighting a cold. If you’re lucky you’ll make it through the rest of the season without catching one. More likely, though, you’ll get one or two, especially if you have young kids in school.
You can’t prevent cold and flu viruses from making their fall appearance, but you can bolster your immune system making it better prepared to fend off attacking viruses. And the remedy might be no farther away than your refrigerator.
While no single food (or supplement) is guaranteed to keep this season’s viruses away, the following eight foods, packed with immune-enhancing nutrients, can give you an edge against cold and flu bugs. Don’t wait until you’re sick to revamp your diet; add these must-have foods to your fall menu now.
Just one Brazil nut packs in two day’s worth of selenium, a mineral that’s essential for mounting a proper immune response against foreign invaders. As an antioxidant, selenium also neutralizes harmful free radicals before they cam damage infection-fighting white blood cells.
Brazil nuts contain more selenium than any other food, thanks to the Amazon jungle’s selenium-rich soil where they grow. One Brazil nut delivers 95 mcg of the mineral; adults need 55 mcg of selenium each day.
Don’t go overboard though. The safe upper daily limit of selenium is 400 mcg, about four Brazil nuts. Ongoing intakes of excess selenium can cause a metallic taste in the mouth, hair and nail loss and fatigue and irritability.
Also eat (for selenium): tuna, shrimp, salmon, beef, chicken, brown rice, sunflower seeds.
This leafy green is an excellent source of vitamin E, an antioxidant nutrient needed for healthy immune function. Several studies indicate that a vitamin E deficiency impairs the action of immune cells. And in elderly individuals, supplementing with vitamin E has been shown to enhance immunity and reduce susceptibility to certain infections.
Vitamin E also works in tandem with selenium to fend off free radicals. You’ll get twice as much vitamin E from frozen spinach as you from fresh. That’s because spinach manufacturers blanch it before freezing to preserve freshness making it denser than raw spinach. (It’s a great addition to smoothies and protein shakes.)
One-half cup of frozen spinach delivers 3.6 mg of vitamin E, one-quarter of your daily requirement (15 mg).
Also eat: almonds, hazelnuts, wheat germ oil, grapeseed oil, sunflower oil, safflower oil, peanut butter.
Spinach manufacturers blanch spinach, or lightly boil it, before freezing to preserve freshness. Therefore, frozen spinach is denser than raw spinach and provides higher levels of vitamins and minerals per serving.
When it comes to zinc, a mineral that’s critical for immunity, you can’t beat oysters. Half a dozen delivers 26 mg of zinc, a three-day supply for women and two and a half day’s worth for men. (Women require 8 mg of zinc each day; men need 11 mg.) Among its many roles, zinc potentiates the action of interferon, a protein that inhibits viral replication. Too much zinc, though, can depress the immune system. The safe upper limit is 40 mg per day.
Oysters are also an exceptional source of B12 (14 mcg in 6 oysters); a lack of B12 can suppress the activity of natural killer cells, a type of white blood cell that destroys virus-infected cells.
If you don’t like raw oysters, buy them canned (cooked) and add them to stews and soups.
Also eat: beef, pork, dark turkey, lobster, fortified breakfast cereal, baked beans, yogurt, cashews.
High in immune-enhancing vitamin C, kiwifruit is easy to blend into smoothies and protein shakes, slice on top of cereal and toss into salads and salsas.
Vitamin C from foods (and supplements) hasn’t been proven to prevent colds or flu but it is vital for immune health. The nutrient stimulates the production and activity of many different types of immune cells.
The official recommended intakes for vitamin C – considered too low by some experts – are 90 mg (men) and 75 mg (women) daily. Two small kiwifruit contain 128 mg.
Also eat: oranges, grapefruit, red bell peppers, green bell peppers, tomato juice, broccoli, Brussels sprouts.
Canned sockeye salmon
Turn to salmon not only for heart-healthy omega-3 fats but also vitamin D, a nutrient that strengthens immunity and boosts immune cells’ production of microbe-fighting proteins. Getting enough vitamin D might guard against the flu. Studies have found that people with lower levels of the vitamin are more likely to get influenza.
Salmon, especially sockeye, is one of the few foods that offers a generous amount of vitamin D. Three ounces of canned sockeye salmon serves up 730 international units (IU), a little more than Health Canada recommends (600 IU) for children aged one to adults aged 70. (Older adults are advised to get 800 IU per day.)
Also eat: mackerel, trout, canned tuna, herring, sardines, milk, fortified non-dairy milk. I also advise taking a 1000 IU vitamin D supplement in the fall and winter and, for some people, year-round.
Not truly artichokes, these small brown-skinned tubers contain non-digestible carbohydrates that feed beneficial, probiotic bacteria in the gut. That’s a good thing since probiotic bacteria, e.g. Lactobacilli and Bifidobacteria species, enhance the activity of the immune system and protect us from sickness-causing germs.
To keep helpful gut bacteria flourishing, include good sources of prebiotics in your daily diet. Prepare Jerusalem artichokes like you would parsnips. Roasted them, sauté them or puree them to make soup.
Also eat: asparagus, bananas, garlic, leeks, onion, whole grains, kefir.
Research from Brigham and Women’s Hospital and Harvard University found that participants who drank black tea for two to four weeks secreted up to four times more virus-fighting interferon compounds than at baseline. Coffee had no effect.
Tea contains L-theanine, an amino acid that primes the immune system in fighting infection.
Also drink: green tea, white tea, oolong tea.
All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.