Carotenoids can help keep your blood pressure in check Original paper

In this meta-analysis of randomized controlled trials, supplementation with carotenoids (lycopene or astaxanthin) reduced systolic and diastolic blood pressure.

The effect of supplementation with carotenoids on systolic blood pressure, diastolic blood pressure, and heart rate.

A total of 1,151 adults (average ages of 23–68), including participants without known health conditions and participants with cardiovascular disease or type 2 diabetes.

A meta-analysis of 19 randomized controlled trials was performed. Three trials each were conducted in Iran, the United Kingdom, Israel, and Japan, 2 trials were conducted in Australia, and 1 trial each was conducted in the United States, Russia, Spain, Poland, and Korea. In the vast majority of trials, the carotenoid administered was lycopene (9 trials; daily dose of 5–30 mg) or astaxanthin (7 trials; daily dose of 6–18 mg). In most trials the comparator was a placebo. The intervention duration ranged from 1 month to 1 year.

Supplementation with carotenoids reduced (improved) systolic blood pressure by 2.5 mmHg and diastolic blood pressure by 1.6 mmHg, with the certainty of the evidence rated as high for both of these outcomes.

Meta-regression analyses indicated a moderating effect of carotenoid dose on systolic blood pressure. In subgroup analyses, the reduction in systolic blood pressure was statistically significant in trials that administered carotenoids in daily doses greater than 10 mg, but not in trials that administered carotenoids in daily doses of 10 mg or less.

In dose-response analyses, the largest reduction in systolic and diastolic blood pressure was observed with a daily dose of approximately 15–20 mg of supplemental carotenoids.