Editor's Note:  Fish oil has numerous health benefits and there are plenty of studies to prove it. However, there are very few studies that show fat loss is one of those benefits. Christian Finn explains...

If you live in the UK, you might have read a recent article in the Daily Mail about a study showing that daily doses of oil containing omega-3 fatty acids, combined with moderate exercise like walking for 45 minutes, can result in significant weight loss.

But taking the oil without exercise, or exercising without taking the oil, does not result in any weight loss, according to researchers from the University of South Australia.

"When we divided up a number of people in our research program, we found that those taking fish oil combined with exercise lost significantly more fat mass than any other group in the study," says study co-author, Professor Peter Howe.

Sixty-eight overweight-to-obese adults took part in the 12-week trial. They were divided into four groups — a group taking fish oil and exercise, another taking just fish oil, a third group taking sunflower oil without exercise and a fourth being asked to combine sunflower oil and exercise.

The clear winners in the study were those in the group who were given small daily doses of fish oil and who walked or ran for 45 minutes three times a week. They lost an average of 4.5 pounds over the three months.

The group that took the sunflower oil, which does not contain omega-3 fatty acids, but who exercised, did not lose any weight. The two groups that did no exercise (including those on fish oil) also lost no weight.

So, how does fish oil work?

According to the Daily Mail article, fish oil increases the elasticity of blood vessel walls and improves the flow of blood to muscles during exercise. This increased blood flow, in theory at least, could accelerate fat loss via an increase in the delivery of lipolytic stimuli to fat cells.

Although it's an interesting idea, I'm not sure that an increase in blood flow would be sufficient to account for all of the extra weight loss seen in the group using fish oil.

Other studies I've seen show that the long-chain omega-3s (DHA and EPA) appear to function as fuel partitioners by directing fatty acids away from synthesis and towards oxidation (see the British Journal of Nutrition for a detailed review, or you can read my summary in The Real Truth about Fish Oil and Fat Loss found in the member's only area of my website).

If you want to increase your intake of omega-3s, eat more deep-colored cold-water fish such as salmon, trout, mackerel and sardines. On days when you don't eat any cold-water fish (or if you don't eat fish at all), use a fish oil supplement.

However, despite the fact it has a number of important health benefits, the idea that fish oil is some kind of magic bullet for weight loss is a myth. You can't just pop a few fish oil capsules and expect the fat to melt away without making changes to your diet and exercise program first.

And while there's plenty of research demonstrating the effect of fish oil on fat loss in rats and mice, research showing a direct effect on body fat in humans is limited in both size and quality.

In fact, other than the study reported in the Daily Mail, I could find only two published trials to show that long-chain omega-3s accelerate fat loss in humans.

To my knowledge, no such studies exist for alpha-linolenic acid (the short chain omega-3 fatty acid found in walnuts and flaxseed). If anyone knows of any that have been done, I'd love to hear about them.
 

Read other articles by Christian Finn

About the Author

Christian Finn is a Certified Personal Trainer and holds a masters degree with distinction in exercise science. He's lectured at a number of universities and private training organizations around the United Kingdom on fitness training, weight loss and the effective use of nutritional supplements. He writes extensively on the subject and his articles have been published in numerous magazines, leading industry journals and websites worldwide, including Men's Health, Men's Health Muscle, Fit Pro (April/May 2001), CAM magazine (February 2003), Image (January 1997), Zest (March 2004), and Body Life magazine (March/April 1997). He was also featured in the July 2004 issue of Muscle & Fitness (UK edition). His website, TheFactsAboutFitness.com, is dedicated to providing its members up-to-date, unbiased information and research on the world of fitness.