Chocolate may be good for the heart, say scientists cautiously, following a large study which found that those who eat more of it are less likely to suffer heart disease and strokes.
Why chocolate-lovers should be better off than those who shun it is not altogether clear, however. While it contains antioxidant flavonoids, known to be protective, it also contains sugar and – especially in the forms popular in the UK – milk powder, which are implicated in weight gain. Obesity is a well-established cause of serious heart problems.
Dieticians suggested that eating chocolate might be helpful because people find it relaxing.
The study was presented at the European Society of Cardiology meeting in Paris and is published online by the British Medical Journal. It was undertaken by Dr Oscar Franco and colleagues from Cambridge University, who wanted to try to establish whether a long-speculated association between chocolate-eating and lower heart disease was real.
The scientists carried out a review of all the relevant and most convincing evidence they could find – seven studies involving more than 100,000 people. They compared the rates of heart disease in those who ate most chocolate with those who ate least.
Five of the seven studies found chocolate – eaten in a variety of forms, from sweet bars to chocolate biscuits and drinking cocoa – to be protective. They concluded that the "highest levels of chocolate consumption were associated with a 37% reduction in stroke compared with lowest levels".
The studies did not differentiate between dark, milk and white chocolate. They also found no effect on actual heart failure.
The authors are cautious about the results, warning that chocolate contains high calories – around 500 for every 100 grams – which can cause people to put on wight and end in heart disease itself. But they think the possible benefits should be further explored, including ways to reduce the fat and sugar content of chocolate.
"This paper doesn't really say eat chocolate to improve heart health – nor do the authors conclude this either. What they seem to say is, those who don't deny themselves a sweet treat of chocolate – white or brown – have better cardiovascular outcomes," said Catherine Collins, a dietician at St George's Healthcare NHS Trust.
"I do feel that the perceived relaxing effect of chocolate (which is recorded in studies as being as soon as the taste and 'mouthfeel' of chocolate is experienced, before the product has hit the intestine and contributed to blood levels of sugar/serotonin whatever) is a contributor – perhaps akin to modest alcohol consumption – a relaxing treat, perceived as a 'de-stressor' and a food whose cost base is so low it's affordable by virtually all."
In the UK, she said, any benefit must be almost entirely due to this relaxation effect, because the cocoa content in products sold here is much lower than in continental chocolate and many people eat it in the shape of chocolate-covered sweet bars, which have very little flavonoid content.
Other scientists were also cautious. Tom Sanders, professor of nutrition and dietetics and head of the diabetes and nutritional sciences division of the School of Medicine at King's College London, warned that many chocolate-lovers deceive themselves. "The problem on chocolate consumption is under-reporting by overweight individuals; they under report food intake, especially forbidden foods such as chocolate. There is a chocolate gap – more chocolate is sold than people own up to consuming," he said.
"Cocoa butter, although a rich source of saturated fatty acids, does not raise cholesterol much because the major saturated fatty acid in it is stearic acid, which neither raises nor lowers cholesterol. The evidence regarding chocolate and blood pressure is mixed, with a recent study showing that cocoaflavonoids increase blood pressure.
"The main problem with chocolate is overindulgence and calories. A little bit of chocolate is OK but the mega-slabs offered cheaply are fuelling obesity in the overweight."
Victoria Taylor, Senior Heart Health Dietitian at the British Heart Foundation, said: "We can't start advising people to eat lots of chocolate based on this research. It didn't explore what it is about chocolate that could help and if one particular type of chocolate is better than another.
"If you want to reduce your heart disease risk, there are much better places to start than at the bottom of a box of chocolates. You can still eat chocolate as part of a balanced diet but moderation is key because this sweet treat is usually packed with saturated fat and calories."
