The researchers at the Norwegian National Institute of Nutrition and Seafood Research (NIFES) have revealed a close link between omega-6 fatty acids in the diet and the development of overweight and obesity. But they have also seen that omega-3 fatty acids counteract this effect.
Omega-6 fat is found in several plant oils and used widely in processed foods. The Norwegian researchers together with American colleagues examined how different intake of polyunsaturated fats affect appetite and fat storage. In the experiment, two groups of mice given different amounts of linoleic acid, a polyunsaturated omega-6 fatty acid that is found mostly in soy oil, corn oil and sunflower oil.
A third group was also treated to a high content of omega-6 (linoleic acid), but also a certain proportion of marine omega-3. The total fat content was the same for all groups, and the mice could eat as much as they wanted.
The results showed that the mice that received the highest amount of omega-6 in food, ate more and became much fatter than the mice that received little omega-6. The researchers found that intake of omega-6, which is within the official recommendations (8 percent of energy from omega-6) resulted in weight gain in mice independently of the mice’s food intake.
The body converts omega-6 to endocannabinoids, neurotransmitters that govern appetite, hunger, energy and fat storage. Producing the body more of the neurotransmitters than we need, does not turn hunger of properly. Thus, we eat more than we need.
Eat more fish
– Based on these results, it may be appropriate to consider whether the increased use of cooking oils with omega-6, especially soybean oil, corn oil and sunflower oil, may be a contributing factor to the development of overweight and obesity in Norway, says research director Bente E . Torstensen at NIFES. Torstensen also noted that the results shows it is wise to eat more fish, as recommended by the authorities.