Mixed results from animal studies of CLA

Conjugated linoleic acid (CLA), a supplement taken to promote weight loss, may cause insulin resistance, according to recent data from rodent studies led by Martha Belury, associate professor of Human Nutrition at the USA's Ohio State University.

In one study, Belury's team found that, while mice on a CLA-supplmented diet lost weight, they accumulated abnormally high amounts of fat in their liver. Although this is a common sign of rapid weight loss it is also a hallmark of insulin resistance, which is the earliest clinical presentation of type 2 diabetes.

Mice who were taken off CLA recovered insulin sesitivity but Dr Belury also found that a second group of mice fed a diet rich in CLA, who were given injections of the prescription insulin sensitizer Avandia (rosiglitazone), neither lost weight nor displayed resistance to insulin.