NEW YORK – A new study shows that fish oil supplements may lower blood pressure in slightly overweight teens, and help their hearts years down the line.

"Starting with a healthy diet and keeping it throughout life may provide better protection than waiting until later when you are more at risk," senior researcher Dr. Lotte Lauritzen of Copenhagen University in Denmark noted in an email.

Adults with high blood pressure have been shown to lower their blood pressure by taking fish oil supplements, and also gain benefits on cholesterol levels. Lauritzen and company looked into whether fish oil's benefits might be useful during the rapid growth period of adolescence.

Her team researched around 80 slightly overweight boys from 13 to 15 years of age. They were randomly divided into two groups. While one received daily doses of fish oill, the other got the same level of vegetable oil (the placebo). The oils were infused in bread, masking the fish taste and smell, and blinding kids to their assigned group.

After 16 weeks, the research team found that kids with the fish-laced bread had lower systolic pressure and lower diastolic pressure, compared to the placebo group.

A drop in blood pressure of 3 mm Hg in adults equals a 15 percent reduction in the risk of stroke.

In early life, blood pressure has been shown to go into adulthood, with adolescents with high blood pressure more likely to suffer the ailment chronically. This happens with diet and exercise habits carried over time, or a “programming” that takes place in the body. Most of the study participants had normal blood pressure.

The team also looked into other heart disease risk factors. These included blood sugar levels, insulin and cholesterol. While there was a change in HDL cholesterol, and non-HDL cholesterol, both were higher in the fish oil group.

"I don't think that the fact that the other were not significant means that fish oil doesn't benefit them," Natalie Riediger, a PhD student at the University of Manitoba in Canada and lead researcher on a recent review of fish oil's role in health and disease, told Reuters Health in an email.

The research used realistic doses of fish oil that other studies, and that may have helped the others to find changes in more risk factors. “I don't think it's practical for people to consume 10 capsules per day as described in other studies," Riediger said.

The vegetable oil used as the placebo also contained a small amount of the same heart-healthy omega-3 fatty acids that are found in fish oil, which may have weakened the contrast between the two groups.

The changes in blood pressure alone confirm Lauritzen's original hypothesis: cardiovascular funtion is susceptible to fish oil's effects during spurts of growth. "There's something going on," she said. "And more research is needed."

She says for now, "Give children good food habits early, including a taste for fish."