If you're pear-shaped and smug, a new study's findings may take you down a peg: For those at slightly increased risk of developing diabetes, fat stored in the buttocks pumps out abnormal levels of two proteins associated with inflammation and insulin resistance. (And that's not good.)
The new research casts some doubt on an emerging conventional wisdom: that when it comes to cardiovascular and diabetes risk, those of us who carry some excess fat in our hips, thighs and bottoms ("pear-shaped" people) are in far better shape than those who carry most of their excess weight around the middle ("apples").
The new study was posted online this week in the Journal of Clinical Endocrinology and Metabolism, and it focuses on a number of proteins, with names such as chemerin, resistin, visfatin and omentin-1, that could one day be used to distinguish between obese people headed for medical trouble and those whose obesity is less immediately dangerous.
The subjects in the study were all people with "nascent" metabolic syndrome — meaning patients who already have at least three risk factors for developing diabetes (large waist circumference, high blood pressure, high triglcerides, low HDL, or "good" cholesterol, and high fasting blood sugar) but no cardiovascular disease or diabetes complications yet.
The researchers found these subjects' "gluteal adipose tissue" — fat in and around the buttocks — pumped out unusually high levels of chemerin, a protein that has been linked to high blood pressure, elevated levels of C-reactive protein, triglycerides and insulin resistance, and low levels of good cholesterol. The blood and subcutaneous fat drawn from gluteal tissue also contained unusually low levels of omentin-1, a protein that, when low, is linked to high triglycerides, high circulating glucose levels and low levels of good cholesterol.
"Fat in the abdomen has long been considered the most detrimental to health, and gluteal fat was thought to protect against diabetes, heart disease and metabolic syndrome," said Ishwarlal Jialal, a professor of pathology and laboratory medicine and of internal medicine at UC Davis and lead author of the study. "But our research helps to dispel the myth that gluteal fat is innocent," he added.