101. Effect of eicosapentaenoic and docosahexaenoic acids on blood pressure in hypertension: a population-based intervention trial from the Tromso Study
- Author
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Bonaa, Kaare H., Bjerve, Kristian S., Straume, Bjorn, Gram, Inger T., and Thelle, Dag
- Subjects
Fatty acids -- Measurement ,Hypertension -- Care and treatment - Abstract
Polyunsaturated fatty acids, which occur in fish oil and other foods, have been claimed to be beneficial for people with hypertension (high blood pressure). Eskimos have a high concentration of polyunsaturated fatty acid in their diet and they also have a low incidence of death from coronary heart disease, a disease of the coronary arteries, which supply blood to the heart itself. However, reports on blood pressure among Eskimos have been contradictory. Fish oil has appeared to lower blood pressure in some studies, but not in all. A carefully designed and controlled study was carried out on 156 mildly hypertensive residents of Tromsa, Norway, to observe the effects of diet on their blood pressure. They had undergone physical examinations, laboratory tests, and electrocardiographic exams. After an initial six-month observation period during which their dietary habits were monitored, subjects were randomly assigned to receive either fish oil components (eicosapentaenoic and docosahexaenoic acids, metabolic products of arachidonic acid breakdown) or corn oil (linoleic acid) in capsule form as supplements to their regular diet. Participants were examined after five weeks and again after 10 weeks. Complete dietary information was collected and evaluated for each subject. Changes in blood pressure, extent of fish consumption, and concentration of fatty acids in blood samples were recorded. Results showed that the subjects receiving fish oil had a significant reduction in systolic (4.6mm Hg), diastolic(3.0mm Hg), and average (3.5mm Hg) blood pressure values, while those taking corn oil had no changes. The subjects in both groups with a high fish intake had lower average blood pressure than those with low fish intake. The effect of fish oil on blood pressure was not significant, however, for subjects who ate the largest amount of fish, and for these subjects, too, their diet was found to account for two-thirds of the changes in blood levels of saturated and monounsaturated fatty acids. The component of fish oil that produced blood pressure reduction is not known, although eicosapentaenoic and docosahexaenoic acids worked for this group, and the effect on blood pressure was correlated with blood levels of eicosapentaenoic but not docosahexaenoic acid. It therefore seems likely that this was the effective component. Not all subjects receiving fish oil experienced lowered blood pressure (32 percent did not). The fattiness of the fish consumed in the diet was found to be a factor here; people who did lower their blood pressure ate less fatty fish. The results demonstrate that fish oil can lower blood pressure in people with mild hypertension. (Consumer Summary produced by Reliance Medical Information).
- Published
- 1990