Study finds fish oil may be useful for overweight teenagers

Oily fish, such as salmon, trout, mackerel and sardines, and fish oil supplements provide the body with the long chain omega 3 fatty acids (EPA and DHA) that are so important for health and which I write about so frequently.  In adults there is indication that fish oil is important for heart health, it can help to lower blood pressure and seems to have beneficial effects on cholesterol levels. 

A newly published study (1) has found that fish oil supplements might be useful for lowering blood pressure in overweight teenage children.  This could be important for heart health in later life.


The study researchers wanted to investigate whether fish oil affects cardiovascular (heart) risk factors during the time of adolescent growth spurt (1).  The study was small, involving 78 teenage boys, aged 13-25, who were slightly overweight.  The boys were given either fish oil, which provided 1.5g of long chain omega 3 fatty acids daily, or vegetable oil (the control group) for 16 weeks.  Neither group knew whether they were taking the fish oil or the vegetable oil since the oils were ‘hidden’ in bread.

After 16 weeks (1) the group eating the fish oil infused bread had higher concentrations of the long chain omega 3 fatty acids EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) in their red blood cells than the group eating the vegetable oil bread, indicating that the fish oil was being well absorbed and incorporated into the body.  The systolic blood pressure was around 3.8mm Hg lower and diastolic blood pressure was around 2.6 mm Hg lower in the fish oil group compared with the control group.  The changes in red blood cell EPA content were inversely correlated with the changes in systolic and diastolic blood pressure i.e. the higher the EPA content in the blood the greater the reduction in blood pressure.

Systolic blood pressure, represented by the top number in a blood pressure reading, is the measure of the phase of the heartbeat when the heart contracts and pumps blood into the arteries.  Diastolic blood pressure, represented by the bottom number in a blood pressure reading, is the measure of the phase of the heartbeat when the heart muscle relaxes and allows the chambers to fill with blood. 

The findings are significant since, in adults a drop in blood pressure of 3 mm Hg corresponds to at least a 15% reduction in the risk of stroke.  In addition to this, blood pressure has been shown to track into adulthood: children and teenagers with higher blood pressure seem more likely to suffer from high blood pressure later in life.  High blood pressure is a risk factor for stroke and heart disease.  More research is certainly needed before any recommendations can be made for fish oil supplementation for heart protection in children however, research showing the benefits of omega 3 fatty acids for health is vast and ever growing.  It would seem sensible to introduce young children to the taste of oily fish early in life and to make oily fish a regular (twice weekly) part of the diet, especially since here in the UK many individuals do not include fish as a regular part of their weekly diet.  If you want to consider a fish oil supplement for yourself or your children it would be worth checking with a medical doctor prior to starting a new regimen.

(1)Pedersen MH et al.  Effects of Fish Oil Supplementation on Markers of the Metabolic Syndrome.  The Journal of Pediatrics.  E-pub prior to print online May 17, 2010. doi:10.1016/j.jpeds.2010.04.001

Written by Ani Kowal