Can chocolate ever be good for us?
Senior lecturer in analytical science Claire Turner looks at the science of chocolate.
Over the years, we all get bombarded with the latest health warnings or stories proclaiming the latest superfood which can provide miraculous health benefits. And very often, the stories completely contradict previous reports about the same item. You know the sort of thing — one month you hear that red wine is good for you, then other scientists come out and say no it isn’t, and then yet a third study might indicate that maybe it is after all. So what are we to make of a report that came out in August 2012 about chocolate having positive health benefits?
Chocolate carries a lot of calories in a small bar, which makes it a high energy food. For this reason, it is a ration of choice for many polar explorers — it can pack a lot of energy in a small space, which is ideal if you have to pull your own sled over miles in sub-freezing conditions. Early polar explorers weren’t aware that chocolate would have been suitable — they thought a high protein diet was more important. In fact, one reason for the failure of Captain Scott’s team to be the first to the South Pole may have been due to their diet. Pemmican (ground meat and fat) and hard biscuits, occasionally supplemented with roast penguin and all washed down with champagne turned out not to be the best idea!
So chocolate is great for people who do a lot of physical activity and need a quick energy boost, but is it so good for the rest of us?
This is a good question. The Cochrane Group report in 2012 showed that consuming an amount of up to 100g of dark chocolate every day may lower your blood pressure by dilating (slightly opening) your blood vessels. This is due to compounds in dark chocolate called flavanols, which act by increasing the production of a gas called nitric oxide — it is this gas which this causes blood vessels to dilate. This effect was small but appeared to be borne out by a statistical analysis. However, it only happened during the first two weeks of dark chocolate consumption; after that the effect was not apparent. But 100g of dark chocolate a day for two weeks is a lot of chocolate! As 100g of dark chocolate contains about 550 kcal, this is roughly a quarter of an average person’s daily calorific requirement of 2000 kcal for a woman and 2500 kcal for a man.
Although there are health benefits due to flavanols, these must be balanced by the need to have a balanced diet. And there are easier ways to lower your blood pressure, like reducing your salt intake or exercising regularly. So don’t beg your doctor for a chocolate prescription just yet!
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Professor Claire Turner is a senior lecturer at The Open University.
This article was previously published on OpenLearn on 31 March 2021 and can be viewed here.
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