Omega-3s to enter weight loss category?

Emerging research looks set to position omega-3 fatty acids as a new ingredient for weight loss foods and supplements, reports Dominique Patton.

There is already evidence to link consumption of seafood with reduced risk of weight gain but there has been little knowledge so far about how this effect is produced.

New studies carried out by one of the top three omega-3 suppliers, Pronova Biocare, have identified a potential mechanism for the weight reduction effect of fish-derived omega-3 fatty acids in mice. The company, which will patent the findings on its concentrated DHA/EPA combination, says that a human trial underway in the Czech Republic may confirm the animal results in the coming months. “No mechanisms have been suggested for this effect to my knowledge. This is very new,” Morten Bryhn, director of research and development for Pronova Biocare, told NutraIngredients.com. Researchers from the company and colleagues at Charles University and the Academy of Sciences of the Czech Republic in Prague report on their results in the December issue of Lipids (vol 39, pp 1177-1185).

They showed that a 60 per cent omega-3 concentrate, containing 50 per cent docosahexaenoic acid and 10 per cent EPA (known as EPAX 1050 TG) increased oxidation of fat by activating genes that break down fat in the mitochondriae and peroxisomes.

The fish oil concentrates not only caused weight reduction in the mice but they also appeared to stop the animals from gaining weight when given free access to food.

Additionally, the omega-3 concentrate reduced the number of fat cells, especially in the abdominal region.

These effects were increased in animals that were put on a 10 per cent calorie reduction regime. The regimen was previously tested in a pilot study, presented at the North American Association for Study of Obesity (NAASO) meeting in November (abstract no 249-P). It involved 20 women with severe obesity (body mass index of more than 40) who were already on a very low calorie diet. The group given the omega-3 concentrate reduced their weight by 20 per cent more than the placebo group after only three weeks of treatment (7.55 kg compared to 6.07kg in the placebo group). BMI was reduced by as much as 15 per cent, says Pronova.

The firm has now initiated a larger study of 30 obese women to confirm these findings. The trial, as well as the previous pilot trial, will also give researchers the chance to check the mechanism identified in mice by analyzing biopsies of fat tissue taken from the patients. “We are planning to present these results at Vitafoods in May,” Dr Bryn said.

“Most products in this area make a lot of promises for fast weight loss. But this really targets the mechanism behind weight gain and offers the possibility for weight loss,” he added.

Being overweight is not only a problem of too much food and too little exercise but also a problem of bombarding genes with signals leading to fat accumulation, explained Dr Bryn.

“A diet rich in red meat and vegetable oils increases accumulation of fat in fat tissue because of a chronic disarray of genes responsible for handling fatty acids and carbohydrates.”