Grapefruit Juice May Help Control Insulin, Reduce Weight Gain - Even with a High-Fat Diet
the MPR take:
Few studies have evaluated the effect of grapefruit juice (GFJ) on metabolism in well-controlled experiments, with contradictory results on weight loss and improved insulin sensitivity. In animal studies, the bitter taste of GFJ and its flavanoid naringin has led to weight loss independent of metabolic effects due to them being adverse to the bitter taste. A new study in PLOS One addresses some of these research issues by evaluating a clarified preparation (cGFJ) with added saccharin; mice were fed either a low-fat or high-fat diet for 100 days with access to water or 50% cGFJ as their sole source of liquids. The mice that were fed a high-fat diet and cGFJ exhibited an 18.4% decrease in weight, a 13–14% decline in fasting blood glucose, a three-fold decrease in fasting serum insulin, and a 38% decrease in triacylglycerol values vs. controls. Mice that were fed a low-fat diet plus cGFJ only experienced a two-fold decrease in fasting insulin. The decrease in blood glucose with cGFJ was similar to that seen in mice with metformin. Don’t trade healthy eating and pharmacological therapy for grapefruit juice just yet – additional studies in both humans and animals are needed to better understand the mechanisms and scope of GFJ actions, the authors note.
Grapefruit juice (GFJ) is relatively rich in nutrients, including vitamins and minerals, and has fewer calories than other many juices. Putative health and weight-loss promoting effects of grapefruit or GFJ consumption have been popularized, but mostly in context of a hypocaloric diet, e.g. the “Hollywood diet”, which limits caloric intake to as low as 3349 kJ per day.