Key Findings:
Limited data are available on its effects on hypertension among subjects in a community setting. Animal and human studies on the association between alpha linolenic acid and blood pressure have been inconsistent. Here data was used from 4594 white participants of the National Heart, Lung, and Blood Institute (NHLBI) Family Heart Study to assess whether dietary consumption of higher amounts of total linolenic acid (α-linolenic and γ-linolenic acid) was associated with a lower prevalence of hypertension and lower resting blood pressure. In this cross-sectional study, a higher intake of dietary linolenic acid (α-linolenic and γ-linolenic acid) was associated with a lower prevalence of hypertension, with only modest evidence for a dose-response relationship. In addition, total linolenic acid was associated with lower resting SBP (≈2.0 mm Hg lower in the highest compared with the lowest quartile of linolenic acid). Linoleic acid was not associated with hypertension. An anti-inflammatory was postulated in that dietary linolenic acid has been shown to be inversely related to (1) the intima-media thickness of the carotid arteries and (2) calcified atherosclerotic plaque in the coronary arteries. In addition, the effects of linolenic acid on blood pressure could be indirect through effects of its metabolites on cell membrane structure and function. Future studies are needed to investigate prospectively the effects of dietary linolenic acid on blood pressure as well as the underlying physiological mechanisms.
ABSTRACT:
Dietary linolenic acid has been shown to be associated with coronary artery disease. However, limited data are available on its effects on blood pressure. We used data from 4594 white participants (aged 25 to 93 years) in the National Heart, Lung, and Blood Institute (NHLBI) Family Heart Study to evaluate whether dietary linolenic acid was associated with prevalent hypertension and resting blood pressure. We used generalized estimating equations to determine the prevalence odds ratios (ORs) of hypertension and adjusted means of systolic and diastolic blood pressure across quartiles of linolenic acid. Mean dietary linolenic acid intake was 0.81±0.35 g per day for men and 0.69±0.29 g per day for women. From the lowest to the highest quartile of linolenic acid, multivariable adjusted ORs (95% confidence interval [CI]) for hypertension were 1.0 (reference), 0.73 (0.56 to 0.95), 0.71 (0.53 to 0.95), and 0.67 (0.47 to 0.96), respectively (P for trend 0.04), controlling for age, sex, energy intake, body mass index, risk group, study site, education, smoking, alcohol intake, exercise, and history of coronary artery disease and diabetes mellitus. Dietary linolenic acid was related inversely to resting systolic (P for trend 0.03) but not diastolic blood pressure (P for trend 0.43). Linoleic acid, an omega-6 fatty acid, was not associated with prevalent hypertension or blood pressure. These data suggest that dietary linolenic acid is associated with a lower prevalence of hypertension and lower systolic blood pressure in white subjects.