Omega Ratio Influences Weight

NICE, FranceEating a diet with too few omega-3 essential fatty acids (EFAs) and with too many omega-6 fatty acids can lead to weight gain that can pass on from parent to child for at least four generations, according to a new study from the University of Nice Sophia Antipolis (JLipid Res. 2010 Aug;51(8):2352-61).

Because obesity has steadily increased during the same time that populations of industrialized Western countries have been exposed to diets rich in fat with a high content of the omega-6 linoleic acid and a low content of the omega-3 alpha-linolenic acid, French researchers examined this possible connection. Experts say human beings evolved on a diet with approximately a 1:1 ratio of omega-6 to omega-3 EFAs, whereas in Western diets, the ratio is 15:1 to 16.7:1.

In order to determine how this imbalance affects obesity, researchers bred male and female mice who were fed high-fat diets (35 percent energy as fat) where the linoleic acid:a-linolenic acid ratio was 28 to 1. While the mices genomes did not change, the offspring showed, over four generations, a gradual enhancement in fat mass occurred with no change in food intake.

Insulin-resistance and inflammation markers levels also occurred, singling an increased risk of type 2 diabetes.

The authors concluded, Thus, under conditions of genome stability and with no change in the regimen over four generations, we show that a Western-like fat diet induces a gradual fat mass enhancement, in accordance with the increasing prevalence of obesity observed in humans.