Should some kids take fish oil supplements?

Fish oil supplements could lower blood pressure in slightly overweight teenage kids, a new study suggests, and their hearts may reap the benefits years later.

"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 to Reuters Health.

Fish oil has been shown to help lower blood pressure in adults with high blood pressure and to have beneficial effects on cholesterol levels. Lauritzen and colleagues wondered if fish oil's benefits might be seen during the rapid growth period of adolescence.

She and her team recruited about 80 slightly overweight Danish boys between the ages of 13 and 15, and randomly divided them into two groups: one received daily doses of fish oil (1.5 grams, or as much as one and a half soft gels) and the other equivalent amounts of vegetable oil (the placebo). The oils were infused in bread, masking any fishy taste and blinding the kids to their assigned group.

After the 16-week study, the researchers noted that the kids consuming fish oil-laced bread had 3.8 mm Hg lower systolic pressure (the top reading) and 2.6 mm Hg lower diastolic pressure (the bottom reading), compared to the placebo group.

In adults, a drop in blood pressure of 3 mm Hg corresponds to at least a 15 percent reduction in the risk of stroke, they point out.

Blood pressure in early life has been shown to track into adulthood, with children and adolescents with high blood pressure more likely to suffer from high blood pressure later in life. This happens either by diet and exercise habits carried over time, or a "programming" that takes place in the body, the researchers explain in The Journal of Pediatrics. Most of the boys in the current study had blood pressure within the normal range.

The researchers also evaluated other heart disease risk factors, including blood sugar levels, insulin and cholesterol. While they found a slight change in HDL cholesterol (the "good" cholesterol) and non-HDL cholesterol - both were higher in the fish oil group - no other differences emerged.

"I don't think that the fact that the other [factors] 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.

Riediger explains that the study used a more "realistic" dose of fish oil than studies that may have found 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," she said.

Also, the vegetable oil used in the placebo bread contained a small amount of the same heart-healthy omega-3 fatty acids that were in the fish oil, which may have weakened the resulting differences between the two groups.