A study by scientists from King's College London has found that relatively small amounts of omega-3 fatty acids from algae can lower blood pressure and could ultimately reduce the risk of cardiovascular disease. This form of omega-3, unlike fish oil, has the advantage of being both sustainable and acceptable to vegetarians.
The research, which is published in the April issue of the Journal of Nutrition, made measurements of cardiovascular function in healthy middle-aged men and women before and after three months supplementation with a placebo or a purified oil rich in the omega-3 fatty acid docosahexaenoic acid (DHA). The DHA was extracted from the marine algae crypthecodinium cohnii. Each subject received both DHA and placebo with a four month break between treatments. The study was conducted ‘double-blind' so that neither the investigators nor the subjects knew which treatment was which.
Results showed that a daily intake of 0.7g DHA lowered diastolic blood pressure by 3mm of Hg. Diastolic blood pressure (resting or background pressure) is a strong risk factor for cardiovascular events. A 3mm reduction in the average population blood pressure could help to prevent thousands of heart attacks and strokes.
Previous studies which have used fish oil have found in excess of 2-3g of omega-3 fatty acids are needed to lower blood pressure; fish oil generally contains much more eicosapentaenoic acid (EPA) than DHA. It has always puzzled scientists why very low intakes of fish (1-2 portions of oily fish a week) may reduce risk of heart disease. This study shows, for the first time, that relatively small amounts of DHA markedly affects the composition of cell membranes and lowers blood pressure.
‘Our findings provide further evidence that relatively small amounts of this form of omega-3 helps promote a healthy heart,' said the study's lead author, Professor Tom Sanders, Head of King's College London's Nutritional Sciences Research Division. ‘There are long-term worries about the sustainability of fish stocks and our results suggest that a sustainable vegetable source synthesised by algae may be useful for preventing cardiovascular disease. Importantly, this form of DHA is acceptable to people who do not eat fish, for example vegetarians.'
Omega-3 fatty acids are considered essential fatty acids and because they cannot be manufactured by the body they must be obtained from food. Omega-3 fatty acids can be found in fish and certain plant oils. Extensive research indicates that omega-3 fatty acids reduce inflammation, help prevent certain chronic diseases such as heart disease and arthritis and play a crucial role in brain function as well as normal growth and development.
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