In a study of overweight adults, Australian
researchers found that a combination of exercise and fish oil
supplements was effective at reducing body fat and improving
cholesterol levels and blood vessel function.
Study participants who took fish oil, alone or with exercise,
saw their levels of "good" HDL cholesterol go up,
while their triglycerides (an unhealthy form of blood fat)
took a dip. Meanwhile, both exercise and fish oil seemed to
cut body fat.
The overall benefits, according to the study authors, suggest
that a combination of exercise and fish oil may improve overweight
adults' cardiovascular health.
Peter R. C. Howe and colleagues at the University of South
Australia in Adelaide report the findings in the American
Journal of Clinical Nutrition.
Numerous studies have shown that the omega-3 fatty acids
in fish may benefit the heart, by lowering blood pressure
and triglycerides, reducing the risk of blood clots and improving
blood vessel function.
There's also evidence from lab studies that fish oil
affects metabolism in a way that can reduce body fat, but
the little research that has been done in humans has yielded
conflicting findings, according to Hill's team.
For their study, the researchers randomly assigned 75 overweight
adults to one of four groups: one that took 6 grams of fish
oil per day; one that consumed fish oil and walked for 45
minutes three days per week; one that consumed pills containing
sunflower oil; and a fourth that combined sunflower oil and
After 12 weeks, the researchers found, volunteers who were
taking fish oil showed greater improvements in their blood
fats and blood vessel function than those who took sunflower
What's more, exercise and fish oil each helped reduce
"Increasing intake of (omega-3 fatty acids) could be
a useful adjunct to exercise programs aimed at improving body
composition and decreasing cardiovascular disease risk,"
Howe and his colleagues write.
However, they point out, this is the first clinical trial
to look at the cardiovascular and weight benefits of combining
fish oil with exercise. More research is needed to investigate
the long-term effects, the researchers conclude.
SOURCE: American Journal of Clinical Nutrition, May 2007.