THE HEALTH BENEFITS OF CHOCOLATE

“Waked in the morning with my head in a sad taking through the last night’s drink, which I am very sorry for; so rose and went out with Mr. Creed to drink our morning draft, which he did give me in chocolate to settle my stomach.”––The Diary of Samuel Pepys, 24 April 1661

Of all the health claims made about all the foods, the wondrous powers of healing attributed to dark chocolate are among the most tantalizing. Throughout its history, chocolate has been claimed to have curative benefits; in fact, many of the earliest chocolatiers started out as apothecaries, enrobing medicines in chocolate to make them more palatable. But in modern times, dark chocolate seems to have shifted dramatically from treat to miracle cure, at least if the headlines are to be believed. As I researched this book and explored the bottomless ocean of articles propounding its health benefits, it was clear why many people believe dark chocolate is good for them. All we need to do, the articles state, is sit back and enjoy a delicious square or two to stave off cancer, lower blood pressure, reduce the risk of heart attack, and enhance our cognitive powers—to name just a few conditions it can supposedly ward off or cure.

But are any of these claims based on robust scientific evidence? Given that most people love the taste of chocolate, are we simply indulging in wishful thinking? Are the big chocolate manufacturers encouraging us to feel this way by pouring millions of pounds into research that invariably finds positive links between the compounds in cocoa and human health? Or were the ancients, who possessed vast knowledge of the healing power of plants, on to something when they administered cacao as a medicine?

Historical records show that from earliest times, cacao has been used for healing. The Aztecs consumed it both as beans and ground into a paste for drinks (sometimes with other medicinal herbs added) to treat an array of complaints, from digestive problems to skin disorders. They even scattered the flowers of the cacao tree in perfumed baths to give them energy.

After conquering the New World in the sixteenth century, the health-obsessed Spanish acknowledged that Aztec medical practices were more advanced than their own, rooted as they were in a detailed knowledge of plants. Once cacao arrived in Spain, physicians slotted it into the prevailing ‘humoral theory’ which, in its simplest terms, categorized diseases and the plants that cured them into the four humours: hot, cold, moist or dry. Confusingly, chocolate fell into more than one category, depending on how it was administered. But it was generally agreed that chocolate was beneficial to health when taken in modest amounts.

Over the course of the following centuries chocolate was consistently hailed by scientists, physicians and thinkers as a cure and therapy for dozens of conditions, as well as a drink that could be appreciated for its taste. Numerous treatises written during this period claimed chocolate could fatten and nourish the weak, energize the exhausted, and improve digestion, bowel function and a range of other ailments. In the eighteenth and nineteenth centuries, chocolate was widely held to promote longevity, and French gastronome Jean Anthelme Brillat-Savarin declared it could improve brain power.

THE POWER OF ADVERTISING

But just as today’s chocolate companies try to tempt us into buying their products by projecting a wholesome image (the iconic picture of the glass and a half of milk is still prominent on the front of every Dairy Milk bar), cocoa purveyors of the past were inclined to a little propaganda.

Chocolate was an expensive, strange and not entirely delicious drink when it first arrived in London in the seventeenth century. Historian, Dr Matthew Green, who conducts tours of London’s erstwhile chocolate houses, has written that chocolate needed a good marketing campaign to propel sales in those early days. “A slew of pamphlets appeared proclaiming the miraculous, panacean qualities of the new drink, which would boost fertility, cure consumption, alleviate indigestion and reverse ageing: a mere lick, it was said, would ‘make old women young and fresh, create new motions of the flesh’,” Dr Green wrote in the Telegraph newspaper. “The commonest claim, however––one inherited from the Aztecs and still perpetuated by chocolate companies the world over today––was that chocolate was a supremely powerful aphrodisiac. The public was sold on this mendacious publicity campaign.”

Today, chocolate companies, like all food manufacturers, are prevented by law from making wild health claims like these. But with sales of milk chocolate stalling in recent years, as consumers become more health conscious, big chocolate manufacturers have poured vast sums of money into chocolate science, to explore the links between cocoa and human health. These studies have often been reported in the media with wildly exaggerated claims. And chocolate companies have done little to correct public perceptions that dark chocolate is a health food.

1920s advertisement declaring the generous milk content in every half-pound Cadbury’s Dairy Milk Chocolate bar

BENEFICIAL PROPERTIES OF CHOCOLATE

There’s certainly promising evidence that chemical compounds found in cacao beans called flavanols may have properties beneficial to human health. Two in particular, epicatechin and catechin, have captured scientists’ interest. Professor Ian Macdonald, an expert in cocoa flavanols from Nottingham University, says these were once thought to be antioxidants––molecules that inhibit cell damage through oxidation. But scientists now believe flavanols serve a different function. Professor Macdonald says cocoa flavanols increase the production of nitric oxide in blood vessels, which improves blood flow. “In theory, this should reduce blood pressure and some studies have shown this, in long-term treatment of people with mildly elevated blood pressure,” he says. And a growing body of research suggests these chemicals might lower the risk of cardiovascular disease. One recent study found that people who ate chocolate three times a month had a reduced risk of heart failure compared to those who ate none. But researchers said eating too much also carried health risks and more studies were needed. Likewise, there is some evidence that brain function in people with cognitive impairment might be improved after taking cocoa flavanols, although other studies have failed to back this up.

Professor Jeremy Spencer, a world leader in flavanols and brain function at Reading University, tells me there is good evidence that cocoa flavanols might temporarily boost our powers of concentration due to increased blood flow to the brain. (This might also explain why chocolate can improve our mood). “You find improvements in cognitive performance on specific tests that involve attention, sustained attention and sustained focus on complex tasks,” Professor Spencer says. “It happens in healthy individuals across all age ranges, and we see the effects during the one or two hours after consuming the cocoa flavanols.” The newest and most exciting area of research is exploring how flavanols, including those found in cocoa, are broken down in the gut. “There’s a lot of interest in how this impacts the population of bacteria in the gut and how this, in turn, effects the immune system,” he says.

All this falls a long way short of the health claims made in the media about dark chocolate being a virtual cure-all. As yet, there is no robust scientific proof that consuming cocoa flavanols reduces our risk of heart attack, improves our health or extends our lives: long-term studies would be needed for that.

One such study is underway. In 2015, Mars began its five-year Cocoa Supplement and Multivitamin Outcomes Study (COSMOS) in conjunction with Harvard Medical School. Involving 18,000 men and women in the US, it is investigating whether daily supplements of cocoa flavanols or a common multivitamin can reduce the risk of heart disease, stroke and cancer.

Crucially, study participants are not eating chocolate. Like most recent ‘chocolate’ studies, COSMOS is using a form of cocoa flavanols that are much more concentrated than those found in commercial chocolate bars and powders. That is because cocoa flavanols are partly or completely destroyed in the chocolate-making process. As a general rule, dark chocolate contains more flavanols than milk chocolate. But contrary to popular belief, the quantity of flavanols does not increase with the darkness of the chocolate. Rather, the flavanol content depends on the variety of cacao beans used and the way they were processed. Milk chocolate contains virtually no flavanols.

Even Mars concedes that chocolate is “not a good delivery mechanism” for flavanols. “They are largely destroyed during the manufacturing of chocolate,” a spokeswoman for Mars told me. “Chocolate therefore contains negligible amounts of flavanols, no matter the amount of percentage of cocoa.” The aim of the COSMOS study is to explore the benefits of cocoa flavanol supplements.

The truth is, we would need to eat vast and unhealthy amounts of dark chocolate to consume enough flavanols to have any beneficial effect, according to scientists. A 2016 German study found that a daily 100mg dose of epicatechin––the amount that reliably causes an improvement in blood flow––was the equivalent of up to 200g [7oz] of chocolate. And the 900mg of flavanols that achieved lower blood pressure in some people was the equivalent of up to 500g [1lb 2oz] chocolate. Scientists, and even Mars, agree that chocolate is too calorific and sugar-laden to be a healthy delivery vehicle for these ‘nutrients’.

Of course, savouring a square of dark chocolate is much healthier than devouring a bar of milk chocolate loaded with sugar, added fats and chemicals. You will want to eat less of it anyway, because it is richer and more intensely flavoured. Studies have also shown that dark chocolate can attenuate hunger more than milk and white chocolate, and the pleasure gleaned from delicious food is good for our overall wellbeing. But there is no proof—so far—that dark chocolate will prolong your life. Sad but true.