Weaknesses in using quasi-quantitative food-frequency questionnaire data to link habitual intake of flavonoids to hypertension incidence

Cassidy et al (1) have recently published a post hoc analysis linking flavonoid intake to hypertension incidence with the use of impressive data sources comprising 2 substantial prospective cohort studies [the Nurses’ Health Study and the Health Professionals Follow-Up Study (HPFS)] and an extension of the comprehensive US Department of Agriculture database on the flavonoid content of foods. The analysis
of the relation between quintile of flavonoid intake and incident hypertension adds further weight to the potential benefits of long-term, consistent consumption of foods rich in flavonoids.