Effects of Docosahexaenoic Acid Supplementation on Blood Pressure, Heart Rate, and Serum Lipids in Scottish Men with Hypertension and Hypercholesterolemia
To investigate the effects of daily supplementation with docosahexaenoic acid (DHA) on coronary heart disease risks in 38 middle-aged men with hypertension and/or hypercholesterolemia in Scotland, a five-week double-blind placebo-controlled dietary supplementation with either 2？g of DHA or active placebo (1？g of olive oil) was conducted. Percent composition of DHA in plasma phospholipids increased significantly in DHA group. Systolic and diastolic blood pressure and heart rate decreased significantly in DHA group, but not in placebo group. High-density lipoprotein cholesterol (HDL-C) increased significantly, and total cholesterol (TC)/HDL-C and non-HDL-C/HDL-C ratios decreased significantly in both groups. There was no change in TC and non-HDL-C. We conclude that 2？g/day of DHA supplementation reduced coronary heart disease risk factor level improving blood pressure, heart rate, and lipid profiles in hypertensive, hypercholesterolemic Scottish men who do not eat fish on a regular basis. 1. Introduction In Scotland, coronary heart disease (CHD) has been one of the leading causes of death, and standardized mortality rates (SDRs) from CHD have been among the highest in Europe for decades although it has been declining since the late 1970s [1, 2]. Evidence from our epidemiological studies showed an inverse relation between death from CHD and fish consumption and that fish consumption in Scotland was at the lowest level among 24-study populations in the world [3, 4]. Diets high in saturated fats, low in fibre, antioxidants, and polyunsaturated fatty acids (PUFAs) were shown to contribute to the higher mortality rates for CHD in Scotland [5]. There have been various public health projects undertaken to facilitate dietary modifications as primary means of the prevention of CHD among the Scottish people. However, dietary efforts to improve CHD risk in Scotland need as well to emphasize the importance of increasing intake of fish and fish products among the general population. Sections of populations, which consume large amounts of marine foods, have a low prevalence of cardiovascular diseases (CVD) [6, 7]. Our epidemiological study indicated plasma docosahexaenoic acid (DHA) level as a useful biomarker of the frequency of fish intake [8]. The intake of fish oils has been associated with a significant reduction in blood pressure (BP) [9], triglycerides, and very-low density lipoprotein cholesterol [10]. The effect of fish oil on reducing heart rate (HR), a CVD risk factor, has also been recognized [11]. We further confirmed a significant inverse association of
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