Health & Science

Does chocolate ward off heart disease?

Eating chocolate could be good for your heart. British scientists analyzed studies involving more than 100,000 people and found that those who reported eating the most chocolate—whether in cookies, candy bars, or milk shakes—were 37 percent less likely to develop cardiovascular diseases and 29 percent less likely to have a stroke than those who ate the least. The results are “promising,” study author Oscar Franco, a lecturer at the University of Cambridge, tells NPR​.org, but he urged people to eat chocolate only “in a moderate manner.” The data can’t explain what causes the link between chocolate and heart health. Previous studies have shown that cocoa products contain antioxidants and anti-inflammatories that can improve blood flow and help regulate insulin levels. The pleasure of eating chocolate may also help reduce stress. But Victoria Taylor, a dietician at the British Heart Foundation, points out that most products that contain chocolate are also loaded with sugar, fat, and calories. “If you want to reduce your heart disease risk,” she says, regular exercise and balanced meals are better places to start than “the bottom of a box of chocolates.”

A gift from the Neanderthals

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We may owe parts of our immune system to our ancestors’ trysts with Neanderthals. A new study shows that many modern humans inherited a significant share of one class of disease-defense genes from our extinct hominid relatives. ”We didn’t just replace” the Neanderthals, study author Peter Parham, a Stanford University microbiologist, tells the San Francisco Chronicle. “We have retained some of them in us.” Scientists discovered last year that up to 4 percent of Eurasians’ DNA descends from that of Neanderthals, but they weren’t sure what those genes did. Now they’ve found that some of them are varieties of HLA, a diverse class of genes that help fight off invading viruses and bacterial infections. Europeans inherited more than 50 percent of one type of HLA from Neanderthals and another extinct hominid species, the Denisovans; among Asians the figure is 70 percent. Africans have no Neanderthal DNA, suggesting that only Homo sapiens who migrated out of Africa and into Europe and Asia mated with the species. The interbreeding likely helped the newcomers survive unfamiliar diseases they encountered in their new environments. Parham says the Neanderthals’ genetic legacy has also increased Homo sapiens’s long-term “capacity to resist infection.”

How the gut affects mood

We may soon be swallowing bacteria instead of popping pharmaceuticals to treat depression and anxiety. Researchers have found that eating a species of bacteria called Lactobacillus rhamnosus, which is found in certain yogurts, cheeses, breads, and probiotic supplements, has a calming effect on mice. When scientists at University College Cork in Ireland fed rodents a broth of L. rhamnosus and then put them in stressful situations, such as swimming or completing a maze, the bacteria-fed creatures seemed “more chilled out” than mice without it, study author John Cryan tells ScienceNOW, and their brains produced fewer stress hormones. The finding bolsters other recent evidence that our gut “microbiome”—the hundreds of species of bacteria that live in our bowels—has a major effect on our mood. Cryan now thinks L. rhamnosus and other bacteria influence mood by way of the vagus nerve, which connects our digestive organs to our brains; when that nerve is disabled in mice, the effects of L. rhamnosus on mood disappeared. The next step is to see if scientists can use the vagus pathway to treat psychiatric disorders without drugs, Cryan says, “by targeting the gut.”

The nation’s union gap

Americans living in the South and the West are more likely to get married­—and divorced—than those residing in the Northeast. That finding, from a new Census Bureau analysis, “surprises people because regions we think of as socially conservative have higher rates of divorce,” Johns Hopkins University sociologist Andrew Cherlin tells USA Today. He links the difference to education levels. States whose residents tend to go to school longer—such as New Jersey, New York, and Massachusetts—have later marriages and fewer divorces. In states with lower education rates, like Alabama, Arkansas, and Texas, there are many young newlyweds but also more divorces than average. The nation’s overall trend, the Census Bureau analysis shows, is toward fewer and later marriages. Today 52 percent of American adults are married, compared with 57 percent in 2000. Couples are now marrying for the first time at a median age of 28 for men and 27 for women, an increase of about 6 years each from 1970. Forty years ago, 42 percent of women married as teens, and 88 percent were wed by 24; today, those numbers have fallen to 7 and 38 percent.