Postmenopausal women who carry more fat on their legs than on their stomach have a lower risk of developing cardiovascular disease (CVD), according to new research*.
Writing in the European Heart Journal, researchers followed 2,600 women of healthy weight with a BMI of between 18 and 25 over a period of 18 years. They found that women of a healthy weight with the highest risk of stroke or heart disease had the most belly fat and the least hip and thigh fat.
The women were all part of the Women's Health Initiative, which began in the mid-1990s, had regular scans to check fat, muscle and bone density. The study found "apple-shaped" women, with more fat around the belly, had a more than threefold increased CVD risk compared with those who were "pear-shaped".
Scientists already know that visceral fat increases the risk of metabolic problems like type 2 diabetes and cardiovascular disease. The reason leg fat might be protective is not well understood, but it is not causing problems elsewhere in the body.
But Professor Qibin Qi, from the Albert Einstein College of Medicine in New York, who carried out this study, said previous research has focused on those who were overweight or obese.
"Our study participants were all women with normal weight. So this message is very important: even for women with a healthy body weight, 'apple shape' or 'pear shape' still matters," he said.
Professor Qi says it is all about trying to reduce belly fat, so the ratio of belly to leg fat is better.
He added: "It is unknown whether there might be some particular diet or exercise which can help relocate fat. Our group is working on this question and hopefully we can have an answer soon.
In the meantime, he said the usual advice about eating healthily and exercising applied.
Dr Sonya Babu-Narayan, associate medical director at the British Heart Foundation, told the BBC: "This study uncovers an interesting link between where fat is stored and your risk of heart attack and stroke, but can't tell us why it exists.
"Future research to uncover how the distribution of body fat is related to these diseases could reveal important new ways to prevent and treat the world's biggest killer."
*Chen G-C, Arthur R, Lyengar NM, et al. Association between regional body fat and cardiovascular disease risk among postmenopausal women with normal body mass index, European Heart Journal, ehz391, DOI: 10.1093/eurheartj/ehz391