Chocolate: a weapon in the war on heart disease?

Tasty new research from the UK has demonstrated that taking a bite of chocolate not only tastes and feels good but might also be healthy for our hearts.


Scientists from the University of Surrey have shown that in real life situations, cocoa flavonals (CF) lowered blood pressure and reduced arterial stiffness as much as some antihypertensive medications – using cocoa supplement and placebo capsules purchased from Amazon.co.uk.

Their findings not only confirmed the results of earlier lab experiments but also revealed that people’s response to CF is biphasic, with considerable daily variation found in individual responses that differed greatly between young, healthy subjects.

The overall analysis showed that CF significantly decreased 12-h systolic blood pressure and pulse wave velocity (PWV) by -1.4 +/- 0.3 mmHg and -0.11 +/- 0.03 m/s, respectively, with peak effects observed within the first 3 hours (1.5 h SBP: -4.9 +/- 2.2 mmHg, PWV: -0.32 +/- 0.17 m/s) and again, 8 hours after ingestion.

Co-author Professor Christian Heiss, from the Department of Clinical and Experimental Medicine at the University of Surrey, said that the positive impact CF have on our cardiovascular system is undeniable.

“Our data confirm that cocoa can improve vascular function and decrease blood pressure and arterial stiffness not only within the first 3 hours after ingestion but also later at 8 hours in healthy normotensive people,” Professor Heiss explained.

“The magnitude of effects… is similar to what standard antihypertensive medications achieve in clinical trials, highlighting the clinical relevance and potential of flavanols for use in clinical practice.”

The researchers also discovered that the effect sizes inversely correlated with baseline blood pressure values both between and within subjects.

“Doctors often fear that some BP tablets can decrease the BP too much on some days, [but] what we have found indicates that cocoa flavanols only decrease BP if it is elevated,” the authors said.

“Specifically, if the blood pressure was low in a person on a certain day, the cocoa flavanols decreased blood pressure and arterial stiffness less. This has important safety and mechanistic implications.

“Whether or not a continuous decrease in blood pressure can be achieved with repetitive administration remains to be investigated.”

The results also showed that the magnitude of responses greatly differed between individuals, with some showing clinically relevant BP decreases in the order of –5 to 10 mmHg.

A few even showing unexpected inverse responses, with statistically significant blood pressure increases – especially for the 1.5 h responses.

This occurred even though the dose of CF used in the study – 862 mg in total – while relatively high, was “in the range that can be achieved with normal diet and would be expected to maximally improve endothelial function”.