Cacao beans, mostly known as the delicious source of chocolates, have been associated with reducing systolic blood pressure.
A study measured the effects of cacao consumption on blood pressure in patients with prehypertension. Subjects consumed 30 grams of dark chocolate per day, and after 15 days, their blood pressure and serum nitric oxide levels decreased significantly.
As an added bonus, other researchers have found that cacao beans contain antioxidants and flavonoids, which possess anti-inflammatory properties and may protect cells from oxidative damage. Read the full study here: