Cocoa Extract Prevents Hypertension in Older Adults with Normal Blood Pressure

Hypertension affects millions of older adults and represents a major cardiovascular risk factor. While short-term studies suggested cocoa flavanols might lower blood pressure, no large-scale trial had examined their effects on preventing hypertension development.

Researchers conducted the COSMOS trial, a randomized, double-blind, placebo-controlled study involving 8,905 older adults (mean age 71) without baseline hypertension. Participants received either cocoa extract supplements containing 500mg daily flavanols (including 80mg epicatechin) or placebo for a median 3.4 years. The primary outcome was incident hypertension based on physician diagnosis, medication initiation, or elevated blood pressure readings.

Overall, cocoa extract showed no significant effect on hypertension development (hazard ratio 0.96). However, subgroup analysis revealed striking differences based on baseline blood pressure. Among participants with normal systolic blood pressure (<120 mmHg), cocoa supplementation reduced hypertension risk by 24% (hazard ratio 0.76). This translated to approximately 0.7 additional months free from hypertension over four years. The protective effect became evident after two years of supplementation.

Interestingly, no benefit was observed in participants with elevated-normal blood pressure (120-139 mmHg), suggesting the intervention works best as primary prevention in those with optimal blood pressure. The mechanism likely involves cocoa flavanols' ability to stimulate nitric oxide production and inhibit ACE activity, supporting vascular health.

These findings suggest a precision medicine approach to hypertension prevention, where cocoa extract supplementation may be most beneficial for older adults maintaining normal blood pressure levels. However, the study relied on self-reported outcomes and included primarily white participants, limiting generalizability.