Fat-burning bacteria
An excess of one of the major intestinal bacteria may encourage obesity, according to two studies, using mice and humans. Most of the 100,000 million bacteria in the gut are firmicutes or bacteroidetes, which help break down food. Obese people tend to have relatively fewer of the latter and more of the former, which seem to help extract more calories from food, AFP reports. In Washington University studies, lean mice given a boost of firmicutes got twice as fat. In another study, dieting boosted the relative levels of bacteroidetes in people from 3 per cent to 15 per cent.
Memorable chemical tracker
A chemical that shows how Alzheimer's affects the brain may be useful in diagnosis and treatments, a University of California, Los Angeles, study shows. The compound FDDNP binds with the plaques and tangles in the brain that are characteristic of the disease and is used with brain imaging, WebMD reports. 'We showed that this is an accurate diagnostic tool,' says researcher Gary Small. 'This could be to Alzheimer's what a cholesterol test is to heart disease and stroke.' And tests on male mice at the University of Southern California suggest that testosterone, levels of which decrease with age, may help guard against Alzheimer's.
Long lives for positives
Optimists may live longer than pessimists, according to a 40-year study of almost 7,000 people in the US. On average, the Duke University, North Carolina, study found the most pessimistic people were 42 per cent more likely to die of any cause than the most positive, Reuters reports. Among the possible reasons are that optimists are less likely to suffer from depression, and may be more likely to have healthier lifestyles.
Healing hands