Flaxseed (Food) for Blood Pressure Regulation

Research suggests that flaxseed and its primary active component, alpha-linolenic acid (ALA), may help lower blood pressure through several plausible biological mechanisms, including suppression of ACE activity, inhibition of an enzyme called soluble epoxide hydrolase, reduced sympathetic nervous system activity, and decreased inflammatory signaling. The evidence base includes animal studies, mechanistic investigations, and at least one randomized controlled trial in patients with peripheral arterial disease that found meaningful reductions in both systolic and diastolic blood pressure with daily milled flaxseed consumption, with the supporting animal and mechanistic research generally pointing in the same direction. Studies indicate that whole flaxseed and flaxseed oil appear to be the more active forms, with lignan and fiber fractions showing less effect in animal models, while one trial in NAFLD patients found no statistically significant blood pressure advantage for flaxseed oil over a comparator oil when both were combined with diet and exercise. Limitations worth noting include the reliance on animal models for much of the mechanistic work, the fact that the primary human RCT was conducted in a population already managing cardiovascular disease on medication, and that a trial specifically designed to test flaxseed as a standalone intervention in newly diagnosed hypertension was still in the protocol stage as of 2014, leaving some questions about generalizability to broader populations unanswered.