EFFECTS OF DIETARY FISH AND WEIGHT-REDUCTION ON AMBULATORY BLOOD-PRESSURE IN OVERWEIGHT HYPERTENSIVES

Obesity is a major factor contributing to hypertension and increased r isk of cardiovascular disease. Regular consumption of dietary fish and omega 3 fatty acids of marine origin can lower blood pressure (BP) le vels and reduce cardiovascular risk. This study examined the potential effects of combining dietary fish rich in omega 3 fatty acids with a weight loss regimen in overweight hypertensive subjects, with ambulato ry BP levels as the primary end point. Using a factorial design, 69 ov erweight medication-treated hypertensives were randomized to a daily f ish meal (3.65 g omega 3 fatty acids), weight reduction, the 2 regimen s combined, or a control regimen for 16 weeks. Sixty-three subjects wi th a mean+/-SEM body mass index of 31.6+/-0.5 kg/m(2) completed the st udy. Weight fell by 5.6+/-0.8 kg with energy restriction. Dietary fish and weight loss had significant independent and additive effects on 2 4-hour ambulatory BP. Effects were greatest on awake systolic and dias tolic BP (P<0.01); relative to control, awake pressures fell 6.0/3.0 m m Hg with dietary fish alone, 5.5/2.2 mm Hg with weight reduction alon e, and 13.0/9.3 mm Hg with fish and weight loss combined. These result s also remained significant after further adjustment for changes in ur inary sodium, potassium, or the sodium/potassium ratio, as well as die tary macronutrients. Dietary fish also significantly reduced 24-hour ( -3.1+/-1.4 bpm, P=0.036) and awake (-4.2+/-1.6 bpm, P=0.013) ambulator y heart rates. Weight reduction bad a significant effect on sleeping h eart rate only (-3.2+/-1.7 bpm, P=0.037). Combining a daily fish meal with a weight-reducing regimen led to additive effects on ambulatory B P and decreased heart rate. The effects were large, suggesting that ca rdiovascular risk and antihypertensive drug requirements are likely to be reduced substantially by combining dietary fish meals rich in omeg a 3 fatty acids with weight-loss regimens in overweight medication-tre ated hypertensives. The reduction in heart rate seen wifh dietary fish suggests a cardiac/autonomic component, as well as vascular effects, of increased consumption of omega 3 fatty acid from fish.