A study looked at the effects of dark chocolate for fifteen days on Nitric oxide (NO) with regards to blood pressure in people with prehypertension. Thirty-two individuals were recruited and divided into 2 groups of 16 each. The treatment group received 30 g/day of dark chocolate daily (containing 70% cocoa) and dietary counseling. Those in the placebo group received 25 g/day of white chocolate daily and dietary counseling. After 15 days, dark chocolate increased NO blood levels compared to placebo (7.70 vs 1.92, respectively) and decreased systolic blood pressure (120.64 vs 131.19). (67)
Cocoa-rich foods may reduce blood pressure. For 2 weeks, participants (n=13) were randomly assigned to receive 480 kcal bars containing either 100-g dark polyphenol-rich chocolate (PRC) bars per day containing 500 mg of polyphenols or 90-g white chocolate (polyphenol-free chocolate [PFC]). At the end of the study, when compared to the PFC group, those in the PRC group experience an average decrease in systolic and diastolic blood pressure (BP) of 5.1 mmHg and 1.8 mmHg, respectively. After the intervention was stopped, BP returned to pre-study values within 2 days. (68)