Walnuts May Reduce Insulin Levels

NEW SOUTH WALES, AustraliaDietary fat can be manipulated with whole foods such as walnuts, producing reductions in fasting insulin levels, according to a study in the European Journal of Clinical Nutrition (2009;63:100815). A total 50 overweight adults with non-insulin-treated diabetes were randomized to receive low-fat dietary advice 30 g/d of walnuts targeting weight maintenance (around 2,000 kcal, 30 percent fat) for one year.

The walnut group consumed significantly more polyunsaturated fatty acids (PUFA) than the control (P=0.035), an outcome attributed to walnut consumption. Most of the effects were seen in the first three months. Despite being on weight maintenance diets, both groups sustained a 1 to 2 kg weight loss, with no difference between groups (P=0.680). Both groups showed improvements in all clinical parameters with significant time effects (P<0.004), bar triacylglycerol levels, but these were just above normal to begin with. The walnut group produced significantly greater reductions in fasting insulin levels (P=0.046), an effect seen largely in the first three months. Long-term effects are also apparent but subject to fluctuations in dietary intake if not of the disease process.