Fish oil containing Omega 3 fatty acids plus moderate exercise can help overweight people shed pounds, even if their diet remains the same, scientists have found.

The Omega-3 fatty acids in oily fish are already known to slow aging in the human brain. The latest study shows they can contribute to significant weight loss by increasing the elasticity of blood vessel walls and improving the flow of blood to muscles during exercise.

Exercise equivalent to aking a 45-minute walk three times a week appears sufficient to produce the weight loss benefit.

Risk of Diabetes, Heart Disease

Professor Peter Howe led a study involving 68 overweight-to-obese adults. PhD candidate Alison Hill monitored the participants during the 12-week trial.

All of the volunteers had risk factors for metabolic syndrome -- a cluster of symptoms, such as hypertension, that are associated with obesity and can lead to Type 2 diabetes or cardiovascular disease.

Some had high blood triglycerides, a type of fat that indicates future heart and arterial disease. Some had insulin resistance or heightened insulin levels, both of which are precursors to diabetes.

The researchers assigned each volunteer to one of four groups: those who took fish oil and walked or ran for 45 minutes three times a week; those who took fish oil without exercise; those who took sunflower oil and walked or ran for 45 minutes three times a week; and those who took sunflower oil without exercise.

No Change in Eating Habits

All of the volunteers ate whatever they wanted. The first group -- those who combined fish oil with exercise -- lost weight, while none of the other groups did.

Those who took the daily doses of fish oil and exercised lost an average of 4.5 pounds over a three-month period.

"If you take the Omega-3 each day and exercise moderately, our studies show your weight will drop," said Hill.

Howe called the impact on body shape and body composition of the participants "the most exciting outcome of the research."