Data from 1,302 participants indicated that flaxseed supplements are associated with significant reductions in both systolic and diastolic blood pressure of about 2.85 mmHg and 2.39 mmHg, respectively.
“The results obtained in the present meta-analysis – a decrease of 2.85/2.39 mmHg after flaxseed supplementation – might be valuable for the hypertension management using nutraceuticals, since Heart Outcome Evaluation study demonstrated that a 3.3/1.4 mmHg reduction was associated with a 22% decline of relative risk of cardiovascular mortality,” wrote scientists from Romania, Iran, Australia and Poland in Clinical Nutrition .
The scientists also report that supplementation for longer than 12 weeks resulted in even greater reductions in systolic and diastolic blood pressure of 3.10 mmHg and 2.62 mmHg, respectively, compared to trials of shorter duration.
The potential biological mechanism are not completely understood, said the researchers, but could be linked to the lignan content of flaxseed. Specifically, a lignan named SDG is known to be an angiotensin-converting enzyme (ACE) inhibitor. ACE inhibitors work by inhibiting the conversion of angiotensin I to the potent vasoconstrictor, angiotensin II, thereby improving blood flow and blood pressure.
The ALA content of flaxseed may also contribute to the potential benefits, they said. This may affect blood pressure either via its ability to reduce the activity of soluble epoxide hydrolase. “It has been shown that these pro-inflammatory oxylipins produced by soluble epoxide hydrolase are responsible for loss of vasodilatation and progression of inflammation in arterial hypertension,” they explained.