National Geographic : 2017 Sep
If only it were as simple as “An apple a day keeps the doctor away.” Nutrition scientists are in fact constantly scruti- nizing the health properties of foods. Everything on this page, along with olive oil and tea, has been the subject of more than 20 studies in the past 25 years, says physician Michael Roizen, chief wellness officer at the Cleveland Clinic. Why? “ They either have unexpected benefits,” he says, “or are commonly consumed but may have risks.” Some foods—like pomegranates and pistachios in the U.S.—rise to nutrition fame because a large company that dominates the production and sales pays for much of the research. But spon- sored studies can shade the science, says Roizen. The National Dairy Council, for instance, “has a huge marketing arm,” allowing it to widely promote the genu- inely nutritious aspects of milk, yogurt, cheese, and more. Some dairy products contain a compound called lecithin, long considered healthy. However, it in- teracts with gut bacteria to produce the damaging compound trimethylamine, which causes inflammation and can lead to disease. Egg yolks also have lecithin in them, so Roizen advises minimal intake. Highly studied foods are not always the ones you should eat. Roizen suggests avoiding low-carb diets that emphasize butter, cheese, and lots of meat. Even healthy-sounding grass-fed beef con- tains carnitine, another trimethylamine producer. “The protein is not different whether it’s grass-fed or grain-fed.” Red wine or a generous splash of un- adulterated extra-virgin olive oil—two top-studied foods—can slightly mitigate the negative effects of meat and dairy. But alcohol is hazardous, and olive oil is high in calories. The best bet, says Roizen, is to follow science, not sensation. Eat vegetables. Instead of meat, choose salmon or ocean trout—they have more good fish oil than most other high-fat, low-mercury species. Drink black coffee (it can be good for the liver). Snack on nuts, but not too many. And for dessert: a bite of dark chocolate. EAT, DRINK, AND BE WARY By Catherine Zuckerman EXPLORE HEALTH REBECCA HALE, NGM STAFF DHA—a type of omega-3 fatty acid found in fish oil—boosts brain power. The pungent sulfur compounds in cabbage appear to give it cancer- fighting properties. Nuts are known to reduce risk of cancer, heart dis- ease, and stroke.