Blood pressure reductions in order of 3 mmHg were observed following 16 weeks of consumption of omega-3 fortified bread by overweight boys going through their adolescent growth spurt, according to new findings from Copenhagen University and the Technical University of Denmark.
“A blood pressure decrease of about 3 mmHg corresponds to a [greater than] 15 percent reduction in the risk of stroke at a whole population level in adults,” wrote the researchers in The Journal of Pediatrics.
“Blood pressure has been shown to track into adulthood, with children and adolescents with high blood pressure more likely to suffer from hypertension later in life. Thus, adolescents with blood pressure in the higher range can be viewed as ‘prehypertensive,’ but whether the tracking of high blood pressure is a result of unhealthy diet and exercise habits carried from childhood to adulthood or whether some programming of blood pressure occurs during adolescence is not known,” they added.
Omega-3s ‘heart’ hearts
The heart health benefits of consuming oily fish, and the omega-3 fatty acids they contain, are well-documented, being first reported in the early 1970s. To date, the polyunsaturated fatty acids (PUFAs) have been linked to improvements in blood lipid levels, a reduced tendency of thrombosis, blood pressure and heart rate improvements, and improved vascular function.
Beyond heart health, omega-3 fatty acids, most notably EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), have been linked to a wide-range of health benefits, including reduced risk of certain cancers, good development of a baby during pregnancy, joint health, and improved behaviour and mood.
The new study extends our understanding of the cardiovascular benefits of the fatty acids, and involved 78 mildly overweight adolescent boys aged between 13 and 15. “We chose to recruit slightly overweight boys, because we wanted clear potential for improvement in the risk factors evaluated,” explained the researchers.
Boys were randomly assigned to consume a supplement of 1.5 grams of omega-3 fatty acids per day or control (vegetable oil) for 16 weeks. The oil was formulated into bread.
At the end of the study the researchers recorded a significant increase in EPA and DHA levels in the red blood cells of the omega-3 group of 1.2 and 6.7 percent, respectively, compared with increases of 0.6 and 4.1 percent in the control group.
In addition, systolic blood pressure was 3.8 mmHg lower following 16 weeks of omega-3-rich bread consumption, compared with control, while diastolic blood pressure was 2.6 mmHg lower in the omega-3 group.
No changes in blood levels of triacylglycerol or insulin sensitivity.
Increases in HDL and non-HDL cholesterol levels were also recorded in omega-3 group of 5 and 7 percent, respectively, compared with 2 and 0 percent in the control group.
“In this study, the non- HDL/HDL ratio, which is believed to be a better indicator of risk, was unaffected by the treatment, and thus the net effect appears to be neutral,” added the researchers.
Commenting on the potential mechanism to explain the apparent benefits, the researchers point to the competition between EPA/DHA and arachidonic acid (AA) in the synthesis of inflammation-related eicosanoids: AA derivatives may stimulate the constriction of blood vessels which would increase blood pressure, while EPA/DHA derivatives may inhibit this pathway.
Source: The Journal of Pediatrics
September 2010, Volume 157, Issue 3, Pages 395-400.e1
“Effects of Fish Oil Supplementation on Markers of the Metabolic Syndrome”
Authors: M. Hojgaard Pedersen, C. Molgaard, L.I. Hellgren, L. Lauritzen