Losing weight with chocolate, plus deep-fried dioxins, edible sunscreens and more in this week's news

Overheating cooks up dioxins in foods
High-temperature frying can trigger the development of potentially toxic dioxins and furans in food, say environmental scientists at the Chinese Academy of Sciences in Beijing. The majority of dioxin-related compounds that they cooked up were isolated from the smoke coming off frying meats or oils, the researchers report online April 26 in the Journal of Agricultural & Food Chemistry. Dioxins most readily formed when food had been fried with flavorings, like the no-calorie sweetener sucralose, that contain chlorine, an essential building block of the toxic pollutants. —Janet Raloff

Diet by chocolate
Compounds in chocolate can inhibit enzymes the body relies on to absorb and use fats and carbs. In test-tube studies, scientists at the Hershey Center for Health and Nutrition and nearby Pennsylvania State University in University Park find that procyanidins — pigmented and antioxidant compounds — and to a lesser extent processed cocoa, ratchet down activity of three important digestive enzymes. The scientists, who report their findings online April 16 in the Journal of Agricultural & Food Chemistry, say that effective concentrations should be achievable in people. They conclude that cocoa-derived compounds demonstrate promise for use in body weight management. —Janet Raloff

A truly green sunscreen
Here’s the brew for a paler you. Regularly downing catechins — the primary antioxidant chemicals in green tea — makes skin less prone to sunburn, a German study finds. Thirty women took part in a 12-week trial in which they drank a liter of a test beverage throughout each day. Compared to women downing a catechin-free drink, the 15 whose beverage delivered 1,400 milligrams of green tea catechins daily ended up with skin that was smoother and better hydrated. Their skin also proved 24 percent less susceptible to reddening following exposure to ultraviolet rays typical of sunlight, the researchers reported online April 27 in the Journal of Nutrition. —Janet Raloff

Meaty cataract risks
A new study links eating plenty of red meat with an elevated risk of age-related cataracts, a potentially blinding clouding in the lens of the eye. Researchers at the University of Oxford in England collected dietary data from more than 27,000 men and women and then followed them for more than a decade. By 2009, 1,484 recruits had developed cataracts. Among people 65 and older, those who ate the most red meat had the highest cataract risk, vegetarians the lowest. Risks for low-meat and fish eaters fell in between, the scientists report in the May American Journal of Clinical Nutrition. —Janet Raloff

Salmonella turns off plant defenses
Although Salmonella typhimurium is best known as a virulent human food-poisoning agent, it can also infect tobacco and survive within the host. Natali Shirron and Sima Yaron of TechnionIsrael Institute of Technology in Haifa now demonstrate that the bacterium accomplishes this by secreting a substance that actively turns off the plant’s germ-killing immune defenses. Salmonella cells then hide out within the plant’s leaves. These new data suggest that at least some plants might serve as a good vehicle to transfer germs from the environment into the gut of a new human host, the researchers conclude April 26 in PLoS One. —Janet Raloff

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