Dietary Fats and Blood Pressure: A Critical Review of the Evidence

Comparisons of blood pressure patterns among populations suggest that low-fat diets or consumption of unsaturated fatty acids decrease blood pressure. However, in most single populations dietary fatty acids and total fat, as determined by diet history, are not significantly correlated with blood pressure. Dietary fatty acids, quantitated by levels in adipose tissue or plasma lipoproteins, had no consistent association with blood pressure. Dietary fatty acids and total fat were not predictive of the development of hypertension over four years in a large cohort of nurses in the United States. Although several dietary trials lacking randomized controls suggested effects of dietary fats on blood pressure, 11 of 12 controlled trials showed no significant effects. All seven double-blind trials, and the two trials of longest duration (one and five years), showed no effect of either varying the content of total fat or of exchanging polyunsaturated for saturated fatty acids. In summary, there is little convincing evidence that the amount or type of dietary fat, varied within customary dietary patterns, affects blood pressure levels in persons with normal or mildly elevated blood pressure.