Recently, doctors at the University of Cologne in Germany repeated the trial, this time using considerably smaller amounts of chocolate (just 6.3 g), but even this had measurable benefits. In this case, BP was reduced by almost 3 mmHg, a small-but nevertheless significant-effect. "On a population basis, we estimate that a 3-mmHg reduction in systolic BP would reduce the relative risk of stroke mortality by 8 per cent, of coronary artery disease mortality by 5 per cent, and of all-cause mortality by 4 per cent," reported lead author Dr Dirk Taubert (JAMA, 2007; 298: 49-60).
How does chocolate work its magic in the body? Last November, doctors in Switzerland, the home of chocolate, reported the results of a battery of detailed tests on the effect of chocolate on 22 of their heart-transplant patients. Using high-tech imaging of the arteries, they found that eating chocolate caused their patients' blood vessels to dilate by nearly 10 per cent. What's more, the effect was almost immediate: vasodilation occurred within two hours. They also found that platelet adhesion-a measure of blood 'stickiness' or coagulation-was significantly reduced, thus helping to prevent blood clots. Finally, chocolate seemed to have strong antioxidant properties, as levels of free radicals in the blood were also substantially reduced (Circulation, 2007; 116: 2376-82).
These are just a few of the many studies that are now completely overturning the conventional medical view of chocolate-which, until recently, was condemned by nutritionists as being too high in both saturated fat and sugar for our own good. Today, chocolate is increasingly being recognized as one of the most potent 'functional foods' around. However, the research data are clear that there's only one type of chocolate that is health-promoting. It's the milk-free, low-sugar kind that is sold in the shops as 'plain', 'pure', 'cooking' or 'dark'-the chocolate most commonly used and consumed in continental Europe.
The dark chocolate bars that have been used in most of the research studies have contained at least 70-per-cent cocoa solids. Although these bars typically contain around 12 g of sugar, the cocoa packs such a healthy punch that it counteracts any adverse effects of the sugar. Diabetics, for example, have no problems with 70-per-cent cocoa bars, as the naturally high fat content of the cocoa dramatically slows the rate at which the sugar is released into the bloodstream. That's also why dark chocolate is such a favourite with followers of the glycaemic index (GI) weight-loss diet. In fact, the GI of 70-per-cent cocoa bars is about 45, or roughly the same as brown rice.
You can reduce dark chocolate's GI score still further by simply increasing the quantity of cocoa solids. Quite a few chocolate makers now offer a choice of strengths up to 98-per-cent cocoa, although many people find such extremely low-sugar versions unpalatable.
Its dark materials
Why is chocolate so special, and what are its magical ingredients?
Although cocoa is high in fat, it is known to have no adverse effects on blood cholesterol. That's because the fat in cocoa ('cocoa butter') is mainly composed of stearic acid, known to be cholesterol-neutral. More than that, cocoa has proved to be actively beneficial to cholesterol. One study found that cocoa increases levels of HDL (the so-called 'good' cholesterol) while decreasing LDL (the 'bad' cholesterol). The key ingredients in chocolate are polyphenols, naturally occurring antioxidants that are particularly rich in cocoa (J Nutr, 2007; 137: 1436-41).
Tests have shown that just 15 g of chocolate can provide over 500 mg of antioxidants, potentially placing dark chocolate at the top of the list of antioxidant sources in the typical Western diet. In contrast, milk chocolate emerges as a poor relation, containing only 5 per cent of the antioxidants of natural cocoa (J Agric Food Chem, 2006; 54: 4057-61).
Cocoa also contains large quantities of flavonoids, especially catechin and epicatechin, and these are among cocoa's most potent ingredients. Recent research has identified epicatechin as the chemical mainly responsible for both vasodilation and the beneficial effects on blood circulation in general (Proc Natl Acad Sci USA, 2006; 103: 1024-9). Indeed, Professor Norman Hollenberg, of Harvard Medical School, has gone so far as to suggest that epicatechin be classified as a vitamin after studying the Kuna people who live on the islands near Panama. These remote islanders drink more than 5 cups of natural cocoa a day-and have very low levels of heart disease, stroke, cancer and diabetes. However, these health benefits are lost when the islanders move to the mainland, says Hollenberg, who has done detailed urine analyses of the two populations. He finds that the key differences between them are their epicatechin levels, the result of the emigrants giving up their natural cocoa consumption (J Cardiovasc Pharmacol, 2006; 47 Suppl 2: S99-102).
How does all of this translate into long-term health? The answer is still somewhat sketchy as, apart from Hollenberg's research in Panama, there's been only one study to ascertain whether or not chocolate helps you live longer. After the Swiss, the Dutch are the next great chocolate lovers and, for 15 years, their scientists tracked the death rates of around 500 elderly Dutchmen, a third of whom never touched cocoa. Although the average intake of the chocolate-lovers was low (just a few grammes of cocoa a day), the effect on longevity was dramatic. Their death rate was half that of the chocolate abstainers, and was almost entirely due to lower rates of cardiovascular and heart disease (Arch Intern Med, 2006; 166: 411-7).
The darker side of chocolate
There are a few downsides in the story of chocolate, however. It can be seriously contaminated with lead, the toxic heavy metal. There's consistent evidence that lead is present at high concentrations in chocolate-indeed, among the highest reported for all foods, according to toxicologists at the University of California in Santa Cruz. The blame is usually placed on the shoulders of the growers, ostensibly because of the high levels of leaded gasoline in the atmosphere where the cocoa plants are grown. But the UC toxicologists say that's completely phoney. Their analyses show that the natural cocoa beans are exceptionally low in lead for a natural food-simply because the beans are protected by their hard cocoa-pod shell. The scientists conclude that the high lead contamination must be due to either shipping or processing of the beans to make cocoa and chocolate products (Environ Health Perspect, 2005; 113: 1344-8).
The cocoa pod also protects the beans from the cocktail of pesticides so often used on conventional plantations. It doesn't protect the workers, though, who are routinely exposed to organochlorine insecticides such as DDT, dieldrin, lindane, chlordane and endosulphan. Of these noxious chemicals, only traces of lindane appear to have found their way into chocolate bars, according to a UK government enquiry (Annual Report of the Working Party on Pesticide Residues, 1998). Lindane is a carcinogenic hormone-disrupting chemical that is banned in many countries.
This makes buying organic chocolate even more important-and from a manufacturer with impeccable credentials.
Another issue is quality. The top cocoa-bean variety is Criollo, followed by Trinitario and finally Forastero. You've guessed it: most of our chocolate is made from the Forastero bean.
Putting the taste to the test
We tested nine of the leading organic chocolate bars available in the high street. Overall, we found that the standard was high in terms of ingredients: none of the organic bars contained any hydrogenated fats, flavourings or colourings, which are often used in ordinary chocolate bars.
The only questionable ingredient was soy lecithin, a compound that is sometimes used by the food industry as an up-market emulsifier. It is added to chocolate to prevent the cocoa butter from separating.
There's considerable debate over the use of soy lecithin. On the one hand, lecithin is a valuable natural source of choline, one of the B vitamins, which helps to build cell membranes. On the other hand, soy is a powerful allergen, to which an increasing number of people are now sensitive. There have been reports of soy causing sneezing, coughing, runny nose, facial swelling, difficulty in swallowing, shortness of breath, excessive perspiration, low blood pressure, anaphylactic shock, fainting and even death. In animals, high doses of soy lecithin have brought about symptoms of mild brain damage (Dev Psychobiol, 1985; 18: 59-66).
Given these potential health problems with soy lecithin, it's remarkable that some organic chocolate manufacturers still feel obliged to include it in a product targeted at health-conscious people-and it's not even necessary. The four chocolate bars rated by our testing panel as tops for taste contained not one molecule of the stuff.
BIONA ORGANIC DARK CHOCOLATE 71% COCOA
WINDMILL ORGANICS LTD
Price: lb1.49 for 100 g
The highest scoring chocolate in our sample, this was given near-perfect marks by most of our testers. It "has the hallmarks of a quality chocolate", said one; "lovely taste and smooth texture" and "tastes like real chocolate" were some of the other comments. The ingredients are simple: just organic cocoa and organic cane sugar, proving that lecithin emulsifiers aren't necessary to create a good product. Biona also claims to use Fair Trade principles in sourcing their raw materials. This, together with a reasonable pricetag, put Biona at the top of our poll.
MONTEZUMA'S ORGANIC 73% COCOA VERY DARK CHOCOLATE
Price: lb1.89 for 100 g
Ex-lawyers Helen and Simon Pattinson founded Montezuma's a mere eight years ago, starting out from a tiny shop in Brighton on England's South coast. They make only one plain dark chocolate bar, containing 73-per-cent cocoa solids, the highest in our sample. The product has just three ingredients: cocoa, cane sugar and vanilla-all organic. All of our taste-testers liked it, and commented on its rich flavour, smooth texture and lack of bitterness. Although this doesn't claim to be a Fair Trade product, the Pattinsons source their cocoa from growers in the Dominican Republic, whom they call their 'friends', which suggests a certain level of ethical business dealings. Our verdict: this is a quality product-and good value for money, too.
BLAKES ORGANIC CHOCOLATE EXTRA DARK 71% COCOA
BLAKES ORGANIC CHOCOLATE
Price: lb1.99 for 100 g
Recently founded by farmer's wife Denise Gleeson, Blakes is based in Ireland. Ms Gleeson also sources her cocoa from farmers in the Dominican Republic, for which she has received a Fair Trade mark as well as full organic certification. The cocoa is processed in Switzerland, where they add a little vanilla and, unusually for this health-conscious market, refined cane sugar. Our panel's reactions were mixed, with some finding the taste "pleasant", while others detected an unusual flavour that one taster described as "yuck". Blakes tends to promote its chocolate products to the coeliac-disease market, as they contain nothing but chocolate and sugar (and no soy lecithin). Our verdict: it's probably okay, but high in sugar.
DAGOBA ORGANIC CHOCOLATE CONCADO 73%
ARTISAN CONFECTIONS CO
Price: lb2.89 for 56.7 g
Dagoba was founded in 2001 (and bought by Hershey's in 2006) by ex-chef Frederick Schilling, then just 30 years old; his aim was to create 'the Art of Chocolate Alchemy'. Well, has he? Some of our testers replied with a resounding 'yes', giving the chocolate top marks for enjoyment. However, the majority thought it was no better than average, with many complaining of a "strong" taste-although this may have been due to the relatively high proportion of cocoa solids. In terms of ingredients, this is up there with the best on the market, containing nothing but organic cocoa and organic cane sugar. Our verdict: this is acceptable, but too pricey.
GREEN & BLACK'S ORGANIC DARK 70% CHOCOLATE
GREEN & BLACK'S LTD
Price: lb1.69 for 100 g
The brand leader in organic dark chocolate (both in the US and UK), and the first British company to be awarded the Fair Trade mark, Green & Black's was founded nearly 20 years ago by well-known US environmentalist Craig Sams. Although the company is now part of Cadbury, Sams sees this as a positive step, a kind of 'reverse takeover' in that G&B may end up infusing the giant multinational with its own ethical philosophy. Unlike most chocolate manufacturers, G&B controls the whole chocolate-making process: crucially, it supervises the cocoa plantations and specifies the growing methods, using only the best Trinitario and Criollo varieties. This means that the end-product should be of high quality. However, it did not go down well with our taste-testers, most of whom found the taste too bitter. On the plus side, it indicates that the product contains high levels of those healthy polyphenols, which are naturally bitter. Nevertheless, that's small consolation, as eating chocolate is meant to be pleasurable, not medicinal. It also contains soy lecithin. Our verdict: disappointing for such a pioneering company.
PLAMIL ORGANICS ORGANIC CHOCOLATE 60% COCOA
PLAMIL FOODS LTD
Price: lb1.89 for 100 g
Plamil is a long-established food company that was originally set up to cater to people with severe food allergies, which suggests that Plamil uses scrupulous manufacturing processes to avoid contamination. They've recently moved heavily into organic sourcing, so the combination should mean high quality. With just 60-per-cent cocoa solids, the Plamil chocolate bar we tested is not one of their most concentrated (they offer bars that are up to 87-per-cent cocoa), but it received very high marks from more than half of our tasting panel: "gorgeous taste and texture", "one of my favourites", "smooth, rich taste" were typical responses. On the flipside, a significant minority hated it, voting Plamil the worst in our sample: "smelt like old socks" and "sickly sweet aftertaste" were some of the comments, with more than one panellist detecting a taint of aniseed (implying less-than-ideal manufacturing purity). It also uses a lecithin emulsifier, but made from sunflowers rather than soy. Our verdict: it's a toss-up as to whether you'll like it.
STAMP COLLECTION PLAIN BAR 70% COCOA SOLIDS
BUXTON FOODS LTD
Price: lb2.29 for 95 g
The Stamp name comes from actor Terence Stamp, who founded the healthfood company after discovering he was allergic to wheat and dairy. This chocolate bar is one of his lines in confectionery. The cocoa is organic and-unusual for this market-the sugar content is fructose rather than sucrose. No doubt as a nod to all those people who are allergic to soy, the lecithin emulsifier is derived from sunflowers. Our (non-allergic) panel, however, were lukewarm towards this bar, with comments such as "not too bad", "not bitter but not particularly nice" and "not as smooth as other bars". Our verdict: this is probably not worth the purchase price. Stamp does, however, do a less organic chocolate bar for children called Peter Rabbit, which our panel found more acceptable.
VALRHONA 'CAO GRANDE' ORGANIC DARK CHOCOLATE 70% COCOA
Price: lb2.99 for 100 g
Valrhona is a high-profile French chocolate company with a pedigree that stretches back 80 years. It owns its own cocoa plantations, grows only the top-notch Criollo and Trinitario varieties, and describes its products with typical Gallic puffery as 'crus', thereby comparing them to fine wines. We chose to test one of its simplest organic products, which was made from cocoa, cane sugar and soy lecithin-all organic. Although lacking a particularly high concentration of cocoa, the bar's "strong taste" was noted by most of our testers, some of whom found it too rich. Overall, our panel didn't think it was nice enough to want to buy themselves. Our verdict: it uses quality ingredients, but it has a high pricetag and is not for sensitive palates.
ORGANIC SEED & BEAN COMPANY DARK 72% CHOCOLATE
NURTURE FOODS LTD
Price: lb1.59 for 60 g
The Organic Seed & Bean Company was founded in 1995 by Stephen Rudkin, a former business-development manager for Green & Black's. "An independent organic food company with a passion for great taste" is how he describes his enterprise, which now offers a range of flavoured chocolate bars-all Fair Trade-sourced, and virtually 100-per-cent organic. Our panel sampled Rudkin's plain dark chocolate bar, which contains 72-per-cent cocoa solids. However, by and large, they weren't impressed, as half of our tasters detected a taint of a non-chocolate ingredient, variously described as "unusual", "pungent" and "strange". This may be due to the presence of a non-organic soy lecithin emulsifier, as the other ingredients are simply organic cocoa and cane sugar. Our verdict: this isn't nearly good enough to justify the pricetag.