A cup of this gourd packs more than 160 percent of the recommended daily amount of vitamin A, key for keeping your skin, eyes, and immune system in good shape. Plus your gut's goblet cells, which help your body digest and absorb nutrients, need the vitamin to work their magic. "If your digestive system isn't healthy, nutrients from food can't get where they need to go," says Lisa Young, PhD, RD, a FITNESS advisory board member and adjunct professor of nutrition at New York University.
- Cook cubed butternut squash in chicken or vegetable broth. Fold into whole wheat mac and cheese.
- Drizzle squash chunks with olive oil and maple syrup and roast until tender. Serve over kale and lentils with honey-mustard dressing.
"Millions of bacteria and viruses constantly bombard your body," explains Vaclav Vetvicka, PhD, the vice chair for research in the Department of Pathology and Laboratory Medicine at the University of Louisville in Kentucky. Beta-glucan, a special fiber found in foods like yeast, oats, barley and mushrooms, can give you an extra boost. Nearly every immune cell in your body has special receptors designed to grab onto beta-glucan, kicking up the activity of white blood cells that, Pac-Man-like, gobble up bacteria and viruses.
- Add a layer of 1/2 cup cooled cooked oatmeal to your yogurt parfait.
- Whip up a savory oatmeal risotto: Simmer 1/3 cup steel-cut oats in 1 cup chicken broth for 30 minutes, stir in 1/3 cup thawed frozen peas, and top with shaved pecorino cheese.
Like oats, these shrooms provide beta-glucan, but that's just the beginning. "Shiitakes have protective compounds and antioxidants that are believed to work together to stimulate immune cells and proteins in our bodies," Dubost says. The result is a lean, mean virus- and bacteria-fighting machine. Shiitakes are so powerful that a study found that their extract helped kill several strains of bacteria, including the deadly MRSA.
- Stir-fry shiitakes with asparagus, onions, hoisin sauce, and sriracha.
- Saute shiitakes in olive oil with fresh sage and serve over warm polenta.
More Health Boosters
You can't always fend off the flu, but selenium-rich foods like shrimp (10 supply 62 percent of your daily dose) could help make it less severe by upping your body's production of cytokines. These proteins tell your immune system to work harder. Without enough of this mineral, you'll feel the flu in your chest, where selenium-starved bronchial cells pump out extra mucus.
- Defrost a handful of precooked shrimp and toss with arugula, oranges and avocado for a salad.
- Cook 1/4 cup brown rice with 1/2 teaspoon curry powder. Stir in 1/2 cup cooked peas, 2 sliced scallions, and 10 diced steamed shrimp.
Where's the zinc? "Even a mild deficiency of this mineral, which is essential for your body's response against all diseases, can weaken your immune system," says Harold Sandstead, MD, a professor emeritus at the University of Texas Medical Branch in Galveston. Fall short and your body won't be able to produce enough interleukin-2, special cytokines that help quash bacteria and viruses. Three ounces of the leanest cuts, like top sirloin or 95 percent lean ground beef, pack more than half your daily zinc.
- Pile sliced grilled sirloin onto romaine leaves. Top with shredded cabbage tossed with fish sauce, lime juice, and rice wine vinegar.
- Saute 3 ounces of 95 percent lean ground beef in a nonstick pan. Stir in 3/4 cup tomato sauce; serve over 2 cups cooked spaghetti squash.
Vitamins and minerals aren't the only players you need to score Teflon defenses. Protein is the MVP. When a virus infects you, it can multiply more than 100 times in as little as an hour. To keep that from happening, your body fights back by churning out antibodies the minute it senses an attack. And to make those antibodies, your body needs protein — ideally, a lean source like a skinless chicken breast, which provides 27 grams for 133 calories.
- Sprinkle cubed grilled chicken breast into quinoa with walnuts, fresh thyme, and roasted grapes.
- Stir shredded skinless rotisserie chicken breast into a steaming bowl of udon noodles with sliced carrots, bok choy, and ginger.
Probiotics, the healthy, live bacteria found in fermented foods like yogurt, could be the secret to fewer sniffles. Researchers at the University of Medicine and Dentistry of New Jersey asked college students to down a daily probiotic supplement or placebo for three months. While each group was found to be equally cold-prone, the probiotic group's colds were two days shorter and 34 percent less severe. Researchers suspect that probiotics may lessen the inflammation that causes symptoms.
- Drink a lassi, an Indian spiced yogurt drink. Blend 1 cup nonfat plain yogurt with 1 cup frozen sliced strawberries, 1 teaspoon sugar and a pinch ground cardamom.
- Dip veggies in tzatziki, a Greek sauce. Whisk together 6 ounces plain nonfat Greek yogurt, 1/2 cup shredded cucumber, 1 teaspoon minced garlic, and 1 tablespoon fresh lemon juice.
According to one study, people with low vitamin D levels are 62 percent more likely to suffer from recurrent strep throat than people with adequate levels. This vitamin regulates more than 290 genes, many of which directly affect our immune systems, explains Michael F. Holick, MD, PhD, a professor of medicine at Boston University School of Medicine. Without enough D, our immune cells can't turn on genes needed to control the release of proteins that fight strep bacteria. You would have to drink about five cups of milk to get a day's worth of D — or you could eat just 3 ounces of rainbow trout. Bonus: The omega-3 fats in the fish ease airway inflammation, so you breathe easier.
- Cut trout fillets into 2-inch strips. Lightly saute and serve in corn tortillas with pineapple salsa.
- Marinate trout fillets in soy sauce and minced garlic. Saute in peanut oil and serve over brown basmati rice with steamed sugar snap peas.
A study in the Journal of the American College of Nutrition found that women who consumed more than 200 milligrams of vitamin C from food daily were half as likely to catch a cold over a four-month period than women whose diets served up less than 100 milligrams. "There's an advantage when you eat foods that contain C: You get other beneficial nutrients at the same time," says Elinor Fondell, PhD, the lead author of the study. A prime example is low-sodium veggie juice. Not only does one 8-ounce serving contain more than a day's worth of vitamin C, but it also supplies 40 percent of your immune-enhancing vitamin A.
- Mix a Mexican mocktail with low-sodium vegetable juice, a dash each of hot sauce and Worcestershire, and a squirt of lime juice.
- Keep single-serve cans in your office drawer for busy days when you don't eat all your veggies.
Just two tablespoons of PB provide 20 percent of your daily cold-busting vitamin E. This antioxidant guards your cells from free-radical assaults that can weaken the protective outer layer that shields them from foreign invaders. It also helps your body's immune response when it's under attack. "Vitamin E from food may help lessen symptoms if you do get a cold," Fondell says.
- Combine 1 tablespoon each peanut butter and honey and microwave until just melted. Drizzle over 2 cups air-popped popcorn.
- Toss spinach with sliced water chestnuts, dried cranberries and diced apples. For dressing, combine equal parts peanut butter, orange juice, and cider vinegar.
When it comes to staying strong, what you eat can work for or against you. Consume these foods with care.
Cocktails: One martini won't hurt you. But more than that may mess with the cilia in your lungs. Normally, these windshield wiper-like mini organs sweep bad bacteria from your airways. Too much booze slows them down, so they're less effective.
Pizza: The delivery staple is a top source of saturated fat in the American diet. Recent research from the University of New Mexico in Albuquerque found that this type of fat may lead to the growth of disease-promoting bugs in your gut.
Lattes and mochas: Liquid calories are a prime cause of weight creep. Over time extra pounds set off a cascade of defense-weakening reactions that can make you prone to many ills, including ulcers and the flu, says a study in Experimental Biology and Medicine.
Originally published in FITNESS magazine, April 2014.