Millions of Americans take fish oil supplements daily because they believe the omega-3 it contains benefits their heart. Until now, scientific studies have been contradictory, but new research published in Physiological Reports finds that taking omega-3 fish oil supplements every day can improve the heart health of seniors after only 12 weeks.

Arteries become more stiff with age, affecting how strongly the heart needs to pump to circulate blood. Pulse wave velocity (PWV) and augmentation index measure arterial stiffness. When the heart sends blood into blood vessels, pressure increases and creates a bulge in the vessel. PWV is the speed at which the bulge ripples through the arteries. When the pressure pulse meets a fork in the arteries, part of the pressure bounces back and combines with the new pulse coming out of the heart. How much the reflected pulse boosts the new one is called the augmentation index. High PWV and augmentation index values indicate stiffer arteries and an increased risk of cardiovascular disease.

Earlier studies had indicated that fish oil could reduce arterial stiffness, and researchers at Pennsylvania State University College of Medicine examined whether omega-3 supplements could reverse the effects of aging in healthy older adults.

Healthy volunteers ages 60 to 80 took two omega-3 capsules twice a day for 12 weeks. Each capsule contained 1000 milligrams of omega-3 (split between 465 mg of eicosapentaenoic acid and 375 mg docosahexanoic acid). PWV, augmentation index, and blood pressure were measured before and after the 12-week program.

After only 12 weeks, PWV values significantly decreased, although blood pressure and the augmentation index did not improve.

"These findings provide support for the concept that increased omega-3 intake may be an efficacious therapy in the primary prevention of cardiovascular disease in aging humans through effects on central arterial stiffness," the researchers wrote. They added that "these effects occurred over a relatively short period of time."