How much good fat is a good amount?

Consumption of omega-3 fatty acids -- found naturally in foods including salmon, walnuts and soybeans -- has shown to lower blood pressure and increase good cholesterol (HDL) in children eight to 15 years old.

However, parents looking to feed their children more of these foods should be mindful that as they gain weight they'll need more of these to make a difference, said lead author Lisa Christian, Associate Professor at the Ohio State University in the US.

Given fluctuations in BMI percentile measures as children grow, it would seem to make the most sense to base dosing on weight alone, Christian said.

In the study, appearing in the journal PLOS ONE, researchers compared fatty acid uptake after kids took a supplement to both overall body weight and body-mass index (BMI).

The findings showed that more a child weighed or higher the BMI category, the lower was the levels of Omega-3 fatty acids such as EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) in their bloodstream.

"Weight, rather than age, may be more meaningful when determining recommended doses. The difference in size between a 7-year-old and a 10-year-old can be quite significant," Christian said.

The study highlights the need for parents trying to ensure their kids get an appropriate amount of omega-3 fatty acids and also highlights the need for weight-appropriate dosing of supplements and medications.

"While this study just looked at fatty acid supplements, it's important to recognise that weight differences could factor into how children and adults respond to many types of medications," Christian noted.