I have always liked chocolate. I grew up on it. Every morning my mother blended a heaping spoonful of cocoa powder with a little milk, some sugar and a touch of salt (to decrease the bitterness). She then stirred the mix into gently boiling milk. This was my breakfast beverage. I was told it was “good for me.” I never questioned that fact. Why should I? It tasted great. I really didn’t see the need to put up a fuss, like say, for spinach. As I got older, the love of hot chocolate naturally paved the way towards chocolate bars. Mostly Lindt and Suchard. But then my chemical education got in the way of these simple pleasures. I discovered that there was fat galore in a chocolate bar! Fifty percent by weight! And lots of sugar to boot. Not great for cholesterol or glucose levels. So, I resigned myself to mostly talking about chocolate instead of eating it. Describing the fascinating chemistry of chocolate turned out to be a great way of interesting students and the public in topics such as fermentation, food cravings, nutrition and even brain function. Everyone, it seems, is captivated by the notion that chocolates contain a chemical, phenylethylamine, which helps us fall in love. Unfortunately, this just isn’t so. The only thing chocolate helps us fall in love with, is chocolate.
Why is that? Why is chocolate the most frequently mentioned food in surveys about cravings? (Actually, this is mostly true for young women, men crave pizza.) While some scientists have argued on behalf of specific compounds such as anandamide or caffeine, which do have potential for pharmacological activity, the consensus opinion is that chocolate is addictive because of its flavour. Not its taste. Flavour is more than just taste. Smell and texture also come into play. This can be very effectively demonstrated by sampling different flavoured jellybeans while holding one’s nose. They are indistinguishable! But identification is no problem once the nostrils are liberated. A pretty dramatic demonstration of the role of smells in flavour detection. When the nose is pinched no air can flow from the mouth through to the nasal passage where our smell receptors are located and therefore the volatile compounds that play such a large role in flavour cannot be detected. That, incidentally, is why people who have colds complain that food doesn’t taste right. Actually, it is their sense of smell that is impaired due to congestion.
Chocolate texture is also important. Cocoa fat has a melting point just around body temperature. So solid chocolate quickly turns into a smooth, luxurious liquid in the mouth. Some have argued that this is a sign from God that we should be eating chocolate. I don’t know about such divine intervention, but there have been signs from the scientific community that moderate chocolate consumption may be good for us. Back in 1996 Andrew Waterhouse at the University of California got the ball rolling with his finding that cocoa beans are an excellent source of a class of chemicals known as polyphenols. These compounds had already received a great deal of attention at the time because their prevalence in fruits and vegetables, and even in red wine, had been linked with health benefits. They act as “antioxidants,” neutralizing those nasty species in our bodies known as “free radicals” which unfortunately are a byproduct of breathing oxygen and which have been implicated in diseases ranging from heart disease to cancer. And now these antioxidants were found in chocolates! In significant amounts! Waterhouse even showed in the laboratory that cocoa extracts can prevent the oxidation of LDL cholesterol (the so-called “bad cholesterol), a reaction that is thought to be a critical step in the formation of deposits in coronary arteries.
Then in 1998, Harvard researchers dipped into chocolate and published a study that made headlines around the world. They followed the health status of nearly 8000 male Harvard graduates, all over the age of 65, and concluded that those who ate one to three chocolate bars a month lived on average a year longer! More chocolate eating, unfortunately, was not better. Men who ate one to three bars a week still did better than abstainers but did not increase their life expectancy by as much as the moderate chocolate consumers. Still, there was an effect. “Eat chocolate and live longer,” had a nice ring to it, as many headline writers discovered.
Since the 1990s, we have had a flood of studies about chocolate. Dark chocolate improves cognition. Dark chocolate reduces the risk of type 2 diabetes. Frequent chocolate consumers have a lower BMI. Flavanols in chocolate reduce blood pressure. Immune cell activity is boosted by ingesting dark chocolate. A spoonful of cocoa powder improves blood flow as measure by dilation of arteries in the arm. People suffering from peripheral artery disease can increase their maximal walking distance after eating dark chocolate with 85 % cocoa powder. While there is certainly some interesting science here, anointing chocolate as some sort of “health food” and adding it to the diet hoping for some benefit is not warranted by the evidence. But writing this has stirred some childhood memories. Time to make myself a cup of hot chocolate. With high-flavanol cocoa powder of course.
