Have you noticed that people who normally shun shots are scrambling to get flu vaccines this year? And that's just the "regular" flu shot — vaccinations against H1N1, or "swine flu," aren't even widely available yet. At Epicurious, we're always looking for a food solution to any problem, so we contacted John La Puma, M.D., the author of "ChefMD's Big Book of Culinary Medicine," for advice about what to eat to boost immunity and fight the flu.
Before we jump into La Puma's list of top flu-fighting foods, here are a few notes from the doctor:
- Swine flu is most likely to be spread the same way as any kind of flu — from person-to-person contact, through coughing and sneezing — and the "best and easiest protection" against flu, including swine flu, is to "wash your hands often, for 15 to 20 seconds, with soap and water, or with an alcohol-based hand cleaner, [rubbing] until your hands are dry."
- You can't get swine flu from eating pork or from drinking bottled or tap water, two common myths about contagion.
- People with immunity problems, such as thyroiditis, rheumatoid arthritis, lupus, and celiac disease, should talk to their doctors before upping their intake of immunity-boosting foods, because "their immune systems are already overstimulated."
- Some reputed immunity-boosters, including garlic, foods high in zinc (such as oysters and peanuts), and foods rich in conjugated linoleic acid (hard cheeses) have not been proven to fight the flu.
Read on for the six foods La Puma says should be in your flu season diet.
Quercetin powerhouse produce: Apples, onions, broccoli, and tomatoes
Quercetin is one of many thousands of flavonoids — substances that are responsible for plants' colors, as well as many of their health benefits. La Puma says that in research performed on mice, stressful exercise increased flu susceptibility but quercetin canceled out the negative effects. The same illness-fighting results were found in a study on cyclists, La Puma says, citing a study from Appalachian State University in Boone, N.C. Quercetin is also believed to aid in disease prevention thanks to its anti-inflammatory properties (to learn more about inflammation, read our feature on the Anti-Inflammatory Diet). So load up on quercetin-packed produce, including apples, onions, broccoli, and tomatoes. Tip: When buying tomatoes, consider choosing organic, which La Puma says have higher levels of quercetin than conventionally grown ones (the same is true for lycopene in tomatoes).
- Recipes to try: Vegetable and Chickpea Ragout; Frisée and Apple Salad with Dried Cherries and Walnuts; Black Sea Bass with Moroccan Vegetables and Chile Sauce
It's not a suburban legend: Chicken soup really does have healing properties, according to La Puma. A steaming bowl of soup (unappetizing language alert) "reduces mucus and facilitates coughing it up." And it seems that chicken soup is more effective at the job than hot water, according to research cited by La Puma. To get the anti-inflammatory and other health benefits of produce too, the doctor suggests making chicken soup with vegetables rather than using store-bought condensed soup or cooking with chicken alone. He shares a favorite recipe for Simple Sopa Azteca on his Web site, and Epicurious has dozens of healthy chicken and vegetable soup recipes, including the ones below.
- Recipes to try: Hearty Chicken Vegetable Soup; Chicken and Hominy Soup; Chicken and White Bean Soup with Herb Swirl
Add fighting the flu to the long list of green tea's health benefits, which also include fighting cancer and heart disease and possible links to "lowering cholesterol, burning fat, preventing diabetes and stroke, and staving off dementia," according to WebMD. Green tea is high in "anti-viral activity against influenza," says La Puma, citing studies involving green tea from the Dr. Rath Research Institute in Santa Clara, CA, and the Department of Biotechnology, College of Engineering, Yonsei University in Seoul, South Korea. While all kinds of tea are made from the same leaves, white and green teas contain higher levels of catechins — the flavonoids thought to be responsible for tea's antiviral properties — than oolong and black teas. Although the studies La Puma cites involved green tea, it's likely that white tea has similar flu-fighting powers. Black and oolong tea do have some catechins and are higher than green tea in other polyphenols, so while they might be the second choice for the flu, they are still good for overall health.
Vitamin D–rich foods: Salmon, light tuna, sardines, milk, and cereal
Vitamin D has been a hot topic in the news recently, with stories about the sunshine vitamin's many health benefits dovetailing with reports that suggest that many of us don't get enough of it. La Puma says experiments in the 1940s showed that mice that received diets low in vitamin D were more susceptible to experimental swine flu infection than those that received adequate vitamin D. While the same has not yet been proven in humans, La Puma and many other experts believe that getting sufficient vitamin D can offer protection against swine flu — the vitamin is believed to cause the production of antimicrobial substances in the body. "In winter, too little vitamin D is made in your skin, because the angle of the sun is too low," says La Puma. "And winter is when you get flu." The good news is that food can pick up the slack. Milk (which is fortified with vitamin D in the U.S.), malted drink mixes, and fortified cereals such as Total Raisin Bran and Whole Grain Total all provide vitamin D, but La Puma says roasted sockeye salmon is the single best source, gram for gram. Roasting the fish allows it to maintain the most vitamin D. "Cooking fatty fish with oil allows the vitamin D to leak out," says La Puma. "Cooking fatty fish in water does retain a little vitamin D, at least in theory, so poaching and steaming work better than frying, deep-frying, and sautéing."
Other good seafood sources of vitamin D are chinook and pink salmon, as well as light tuna and sardines packed in oil. "Packing (but not cooking) fish in oil allows retention of omega-3s and vitamin D," says La Puma. But, he warns, "pouring off the oil from canned fish pours off the vitamin D too."In addition to making the dishes below, try omitting the step of draining the canned fish in recipes such as Sicilian-Style Pasta with Sardines or Tuna, White Bean, and Red Onion Salad. If you are not a fan of the flavor or extra calories in oil-packed fish, don't worry: Water-packed varieties do have some vitamin D, just not quite as much as oil-packed. For more information, see Epicurious's sister site Nutrition Data's list of foods highest in vitamin D. Bumble Bee Chunk Light Tuna was the top pick for oil-packed varieties in Epicurious's Canned Tuna Taste Test.
- Recipes to try: Baked Sockeye Salmon with Bell Peppers and Capers; Wild Salmon with Pearl Couscous, Slow-Roasted Tomatoes, and Lemon Oregano Oil; Penne with Tuna, Basil, and Lemon
Yogurt and kefir with live active cultures
Epicurious's recent blog post Fight Off the Flu with Delicious Yogurt Recipes discussed a study that suggests that probiotics — the friendly bacteria found in yogurt and some other foods, as well as in pill form — may reduce cold and flu symptoms. La Puma cites the same study and says that probiotics have been shown to reduce the incidence and duration of fever, cough, and runny nose by 73, 62, and 59 percent in kids ages 3 to 5, respectively. While the study was done with supplements, La Puma says we "foodistas" may prefer to get our probiotics from what we eat. When buying yogurt and kefir, be sure to look for the "Live and Active Cultures" label and choose one with as many different strains of cultures as possible. For more on how different strains affect health, see probiotic confusion from Nutrition Data. As the author of the article, Monica Reinagel, M.S., L.D./N., notes, friendly bacteria can also be found in fermented foods such as kimchi, kombucha, sauerkraut, and miso, and "eating a variety of fermented foods, which provides a wider variety of bacterial strains, might offer a wider range of benefits."
- Recipes to try: Moroccan-Style Vegetable Stew with Harissa Yogurt Sauce; Fig Salad with Goat's Milk Yogurt and Pepper Cress; Roast Chicken Breasts with Garbanzo Beans, Tomatoes, and Paprika
Chiles such as serranos, jalapeños, and poblanos
Spicy peppers don't just help clear your sinuses, they're also a great source of vitamin C, which "has been tested in influenza A and been shown to reduce the incidence of pneumonia that comes with flu," says La Puma. The vitamin has antiviral properties and stimulates antibody production, explains La Puma. Not a chili-head? Sweet red bell peppers are also packed with vitamin C, as are guava, kiwi, oranges, green bell peppers, strawberries, Brussels sprouts, cantaloupe, and papaya, according to the USDA.