Eat these foods for better immunity during flu season
We had a relatively cool summer here in the Northeast. But, when I awoke with an intense craving for a pastured pork chop, fingerling sweet potatoes and a heap of garlicky kale — for breakfast — I knew that fall had officially arrived. Our bodies inherently respond to changes in season. That's why we crave lighter foods in late spring and summer and heavier foods in the fall and winter.
After the fall equinox, the days get progressively cooler and shorter and according to Ayurveda — a healing systems developed thousands of years ago in India — our body responds by increasing its digestive fire. This enables us to consume the denser foods that our bodies naturally crave when the temperature drops: root vegetables, meats, grains, nuts and seeds.
Ayurvedic practitioner John Douillard explains that eating foods harvested in late summer triggers a natural cleansing reaction in our body that helps us transition to colder weather and a winter diet.
Douillard elaborates: "Apples dissipate heat, scrub intestinal villi and act as a natural detoxifying diuretic; watermelons are diuretics, while pomegranates are liver and blood cleansers."
Transitioning to a "winter" diet
Flavor, taste and texture to try: Since winter is cold and dry, the body will be best nourished by foods that are sweet, sour, salty/heavy, oily, moist or hot — like soup, stews, steamed vegetables and warm herbal teas.
Temperature matters: Warm foods are ideal, as long as they are cooked with easy-to-digest oils like ghee or olive oil. Avoid (or limit) foods that are bitter, astringent or light — less (raw) salads, frozen smoothies, chips, salsa. You’ll also want to avoid consuming cold food and cold drinks, which douse your digestive fire and decreases immunity.
Limit immunity robbers: Caffeine, sugar, alcohol and processed foods.
8 Seasonal immune-boosting foods for fall and winter
Eating deeply colored, locally grown fall produce — on abundant display at farmers markets this time of year — nourishes our immune system as we transition from fall to winter (October through March). In Ayurveda, the dryness and coldness of winter is balanced out by foods with opposite qualities, like earthy, sweet-tasting vegetables, which are also chock-full of immune-supporting nutrients.
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A rich source of phytonutrients, including polyphenols (compounds that add astringency and bite to foods) and flavonoids, like quercetin, apples contain antioxidants and anti-inflammatory properties that help boost immunity. The flesh of the apple contains soluble fiber, which a University of Illinois study, showed has immune-strengthening properties. Apple skins contain phloridzin, a polyphenol that can help lessen the damage caused by high blood sugar — they are also a source of insoluble fiber, which helps cleanse the bowels.
Since apples rank No. 1 on the Environmental Working Group’s Dirty Dozen Plus list — retaining the highest level of pesticide residue of all produce tested — look for organic or minimally sprayed apples at your local farmers market. According to Ayurveda, it's best for winter digestion to eat apples cooked.
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A good source of immune-boosting vitamin C, beets are also a very good source of manganese, a mineral that supports immune function by enhancing natural killer cells and macrophage (white blood cell) activity. Beets are rich in essential minerals — potassium, copper, magnesium, phosphorus and iron — and an excellent source of folate and vitamin B6. Traditionally, deeply colored beets (thanks to betalain pigments) have been valued for providing antioxidant and anti-inflammatory support as well as for cleansing the blood and liver. High in fiber, beets can help relieve constipation. Ayurveda advises to cook your beets.
3. Brussels sprouts
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One cup of cooked Brussels sprouts contains double the amount of immune-boosting vitamin C than that found in an orange — it’s also an excellent source of vitamin K, which promotes healthy blood clotting function. Brussels sprouts provide antioxidant support by way of vitamin A, the mineral manganese and flavonoids, such as quercetin and kaempferol.
Research suggests that not only do Brussels sprouts have a detoxifying effect that helps fight cancer and other diseases — they may also protect our DNA, which can be damaged when natural chemicals in the cells replicate faster than normal.
From an Ayurvedic perspective, Brussels sprouts, which are harvested from winter through spring, are a seasonal food, providing the right kind of fiber for our digestive tract and for strengthening our immune system. Eating Brussels sprouts during the fall and winter can help prevent (bad) bacterial overgrowth, like H. pylori, in the digestive system.
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Boasting antibacterial, antiviral, antifungal, antiparasitic and anticancer properties, studies suggest that garlic bolsters the immune system. During World War I, garlic was used as an antibiotic — researchers later discovered that it is the allyl sulfide in garlic that exerts an antibiotic effect. Garlic also contains allicin, which, in large quantities (we're talking 7 to 28 garlic cloves daily!), confers cardiovascular benefits, including a potentially positive effect on blood cholesterol. While raw garlic can be too "heating" for some Ayurvedic body types, especially in the summer, it is the antidote to colds and flus during the winter.
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Organic pigments called carotenoids give pumpkins their classic orange color and are an excellent source of beta-carotene, which converts to immune-boosting vitamin A. Pumpkin also contains alpha-carotene, an antioxidant that is associated with living longer, according to a study published in the Archives of Internal Medicine (now JAMA Internal Medicine). It is thought to effectively inhibit the growth of cancer cells in the brain, liver and skin. Vegetables with alpha-carotene are also strongly associated with decreased risk of lung cancer.
6. Sweet potatoes
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There are about 400 varieties of sweet potatoes in a rainbow of colors — cream, tan, yellow, orange, pink and purple. In season, during November and December, these naturally sweet root tubers possess antioxidant, anti-inflammatory and cancer-fighting properties.
Orange-fleshed sweet potatoes are one of the best sources of beta-carotene. And, studies have shown that eating sweet potatoes effectively raises our blood levels of vitamin A, supporting our immune system. However, because beta-carotene is fat-soluble, you should eat sweet potatoes with at least three grams of fat — for example, one tablespoon of olive oil or grass-fed butter — to ensure maximum absorption of the beta-carotene.
A very good source of vitamin C, B vitamins as well as minerals (like manganese, copper and potassium), sweet potatoes are a good slow carb that helps stabilize blood sugar.
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A member of the Brassicaceae family of cruciferous vegetables (cabbage, kale, broccoli), turnips are rich in sulfuric compounds, especially glucosinolates. A good source of antioxidants, minerals, vitamins and fiber, turnips are a good source of vitamin C, potassium and most of the B vitamins.
In addition to being high in iodine — an adequate amount of which is needed for optimal thyroid function — turnips also contain hydroxycinnamic acids, powerful antioxidants that protect the body from free radicals, act as an anti-inflammatory and have cancer-fighting effects.
For maximum nutritional benefits, eat the turnip greens as well as the root vegetable: They are an excellent source of hard-to-get minerals.
8. Winter squash
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The orange-yellow-colored flesh of winter squash, including butternut, acorn, kabocha and Hubbard, are excellent sources of vitamin A (beta-carotene) and vitamin C as well as anti-inflammatory nutrients, such as omega-3s and vitamin K, all of which support a strong immune system that can ward off colds and flu.