In an 18-week study researches looked at relationship between polyphenol-rich dark chocolate and blood pressure. Polyphenol are thought to act as antioxidants and are known to protect cells against damage. Between January 2005 and December 2006, 44 participants (24 women, 20 men) aged 56 through 73 years in Germany with untreated upper-range prehypertension or stage 1 hypertension received 6.3 g of dark chocolate containing 30 mg of polyphenols or matching polyphenol-free white chocolate per day. At the end of the study, researches saw a drop in systolic blood pressure by -2.9 (1.6) mm Hg (P < .001) and diastolic BP by -1.9 (1.0) mm Hg (P < .001) among participants consuming dark chocolate. The proportion of subjects with hypertension decreased from 86% to 68%. (69)
