A daily bar of dark chocolate could protect against heart disease – but it has to be enriched with olive oil, experts have said.
Experts found the food boost the number of cells responsible for repairing blood cells to circulate in the blood.
This prevented the blood vessels from hardening and narrowing – a process called atherosclerosis.
The cells are called endothelial progenitor cells (EPCs), stem cells that are important in vascular healing.
“A healthy diet is known to reduce the risk of cardiovascular disease,” said Dr Rossella Di Stefano, a cardiologist at the University of Pisa, Italy.
“Fruits and vegetables exert their protective effects through plant polyphenols, which are found in cocoa, olive oil, and apples.
“Research has found that the Italian Panaia red apple has very high levels of polyphenols and antioxidants.
“We found that small daily portions of dark chocolate with added natural polyphenols from extra virgin olive oil was associated with an improved cardiovascular risk profile.
“Our study suggests that extra virgin olive oil might be a good food additive to help preserve our ‘repairing cells’, the EPC.”
The study involved 26 volunteers of which 14 men and 12 women with at least three cardiovascular risk factors including smoking, high cholesterol, high blood pressure or a family history of cardiovascular disease.
They were given 40g of dark chocolate daily for 28 days.
For two weeks the chocolate contained ten per cent extra virgin olive oil and for the next fourteen days it contained 2.5 per cent Panaia red apple.
Progression of atherosclerosis was assessed by metabolic changes including blood fats, blood pressure and levels of circulating endothelial progenitor cells (EPCs).
After 28 days, the researchers found that the chocolate enriched with olive oil was associated with significantly increased EPC levels compared to both the start and those eating the apple-enriched chocolate.
Experts also said the olive oil-enriched chocolate was associated with increased levels of good cholesterol – and even a lower blood pressure.
Olive oil-enriched chocolate was associated with significantly increased “good” cholesterol and decreased blood pressure compared to the start.
“Consumption of enriched dark chocolate resulted in modification of metabolism with potential long-term consequences on cardiovascular health within four weeks,” said Dr Di Stefano.
“However, only extra virgin olive oil dark chocolate consumption results in improvement of endothelial function, associated with the increase of EPC circulating levels, probably due to the additive effect of extra virgin olive oil polyphenols.”
The study was presented at the European Society of Cardiology Congress in Barcelona.