Eating a handful of dates daily can lower your blood pressure by 14 to 8 points [mmHg] within a month and a half, according to a human study published in the Journal of Nutrition College in 2022.

Study
Researchers at Diponegoro University in Indonesia gave 20 adults over 60 with slightly elevated blood pressure 100 grams of dates - ajwa dates, to be precise - every day for six weeks. An ajwa date weighs 8 to 10 grams. The participants ate approximately 10 to 12 dates per day.

A comparable control group received information about the risks of elevated blood pressure and what they can do to reduce it.

Results
The subjects' BMI did not change during the experiment. This was true for both groups.

In the control group, systolic and diastolic blood pressure increased by 2 and 3 points, respectively. In the experimental group, systolic and diastolic blood pressure decreased by 14 and 8 points, respectively. The decrease in the date group was statistically significant.

Active ingredients
The researchers suspect that the reduction in blood pressure in this trial is primarily due to phenols in dates. 100 grams of fresh dates provides 200-400 milligrams of phenols, expressed as gallic acid equivalents. [Saudi J Biol Sci. 2021;28(6):3566-77.]

We wonder if that's the whole story. In a German study published in 2009 in the British Journal of Nutrition, in which subjects were given 150 milligrams of quercetin daily for 6 weeks, systolic blood pressure decreased by less than 3 points. [Br J Nutr. 2009 Oct;102(7):1065-74.]