chocolate
by Jenny Bryan
Chocolate beans are the dried and processed seeds of the yellow-green pods which hang from the trunk and stems of the cacao tree in equatorial America, Africa and Asia. Once used as local currency in parts of Central America, the true worth of chocolate beans to European palates was only recognised when the conquistadors brought them back to Spain as part of their Aztec treasure.
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The flavour of chocolate is largely dependent on its polyphenol content. Polyphenols are a broad class of anti-oxidant chemicals found in plants, and the more of them in chocolate, the sharper and stronger the taste. Since polyphenol levels are affected by local environmental factors and by the way in which the chocolate is processed, the flavour – as any chocoholic will tell you – is highly variable.
why is chocolate good for you?
A 100 gram strip of chocolate will give you about 500 calories of energy, 8 grams of protein, 60 grams of carbohydrate, 30 grams of fat, and small amounts of calcium and iron. But the possible health benefits come from the polyphenols in chocolate, especially the largest group, called flavonoids.
Laboratory tests have demonstrated the anti-oxidant effects of polyphenols in chocolate on LDL-cholesterol – the so-called 'bad cholesterol' found in the blood stream, which is linked to an increased risk of heart disease. It is the oxidation of LDL-cholesterol which is thought to trigger changes in arterial walls, leading to 'hardening' of the arteries (atherosclerosis), blockages and eventual heart attacks and strokes. In one study, cacao (cocoa) powder extract was found to have anti-oxidant activity somewhat greater than that of red wine, whose mildly protective effects against heart disease are well known.
Other studies have suggested that chocolate may inhibit blood clot formation, rather like aspirin, and so have further beneficial effects on heart disease development.
what's the evidence?
Recent publicity about the health-giving properties of chocolate has focused on two studies carried out in the USA, both with links to chocolate producers. At the University of California, volunteers ate 25 gram pieces of dark chocolate or chunks of bread and gave blood samples two and six hours later. Those who had eaten the chocolate had lower levels of platelet activity – the blood particles which stick together to form the core of blood clots.
In the second study, reported from Penn State University, researchers compared the effects of a diet low in flavonoids with one which included 22 grams of cocoa powder and 16 grams of dark chocolate per day, in pudding, biscuits or cakes.
After the chocolate-rich diet, oxidation of LDL-cholesterol was about 8% slower than after the ordinary diet, and the anti-oxidant capacity of the blood was also slightly raised. In addition, there was a small increase in 'good' (HDL) cholesterol.
But how do such changes relate to heart disease risk?
chocolate and heart disease
No clear, direct link has been established between chocolate consumption and heart disease.
The most widely quoted research was carried out amongst nearly 8,000 middle aged and elderly Harvard University graduates who completed a questionnaire about their sweet intake in 1988. Researchers checked the death certificates of the 514 men who had died up to the end of 1993. They found that the sweet eaters had a 17% lower death rate than those who professed hardly ever to eat sweets. Those at lowest risk were men who had a relatively modest consumption (1-3 times per month), with a 36% reduction in death rate. As sweet consumption increased, mortality crept up, but never reached the levels of non consumers. Overall, men who indulged lived almost a year longer than those who didn't.
The main drawback of this study was that it didn't differentiate between sweets and chocolate, so no one can be sure whether it was chocolate or some other form of confectionary that was helping the men to live longer.
Chocolate was the focus of another study, also carried out by Harvard researchers, amongst nurses. But no reduction in heart disease was seen in consumers who professed to eat chocolate up to three or four times a week, compared with rare consumers.
what about the drawbacks?
Need you ask! A small bar of chocolate gives a woman about a quarter of her recommended daily calorie intake in just a few glorious mouthfuls. In addition to its anti-oxidant polyphenols, chocolate also contains significant levels of saturated fats – the sort more commonly found in animal fat and linked to an increased risk of heart disease.
Chocolate supporters point out that chocolate provides only 5-6% of total fat and energy intakes for young Britons and, in Switzerland, which has the highest chocolate consumption in the world, obesity and heart disease risks are amongst the lowest in western Europe.
which type to choose
If you are convinced of the health-giving properties of chocolate then you should go for rich, dark chocolate with 70% cocoa solids and low levels of cocoa butter. But everything in moderation. Bear in mind that, in the studies demonstrating anti-oxidant and anti-platelet effects, subjects consumed the equivalent of only one or two squares of chocolate a day. And, if you're a chocoholic, that's barely enough to make your mouth water.
help and info
Channel 4 is not responsible for the content of third party sites.
organisations
British Heart Foundation
14 Fitzhardinge Street
London W1H 6DH
Heart Information Line: 08450 70 80 70 (Mon-Fri 9am-5pm)
Website: www.bhf.org.uk
Provides a range of information about the causes, prevention and treatment of heart disease. Website contains a glossary, details of publications, plus practical advice on how to protect yourself from heart disease.
British Nutrition Foundation
High Holborn House
52-54 High Holborn
London WC1V 6RQ
Telephone: 020 7404 6504
E-mail: postbox@nutrition.org.uk
Website: www.nutrition.org.uk
Features useful information on nutrition tailored to people of all ages and stages of life. Nutrition scientists can answer queries by phone, fax or e-mail and is a source of reliable information on current nutrition issues.
websites
Chocolate Information Centre
www.chocolateinfo.com
Chocolate and health information for researchers and health professionals, established by Mars Inc. Includes details on fat and sugar content, the nutritional value of chocolate and new research findings.
International Cocoa Organization
www.icco.org
The main forum for information on cocoa; promoting cocoa research and studies of the economics of cocoa production, consumption and distribution.
Institute of Food Research
www.ifrn.bbsrc.ac.uk
UK organisation working in association with UK government departments, the European Commission, research councils and industry and consumer groups. Has keyword search facility for recent research information on most foods.
International Food Information Council
www.ific.org
US site giving information on food safety, nutrition and health based on scientific evidence.
Medical facts about chocolate
www.bupa.co.uk/health_information/ ..
Enlightening facts from BUPA about chocolate and health.
Seventypercent.com
www.seventypercent.com/pod/feature8.asp
Article by Chris Chung entitled 'Be healthy, eat more chocolate', which explores some of the mythical and factual powers of chocolate.
reading
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Cholesterol Cures: More than 325 natural ways to lower cholesterol and live longer from almonds and chocolate to garlic and wine by William P Castelli (Rodale Press, 2001) |
'Effects of Cocoa Powder and Dark Chocolate on LDL Oxidative Susceptibility and Prostaglandin Concentration in Humans' by PM Kris-Etherton and others, in American Journal of Clinical Nutrition, vol 74 (November 2001), pages 596-602 |
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'Letter to the Editor' by FB Hu and others, in American Journal of Clinical Nutrition, vol 72 (October 2000), pages 1059-1060 |
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'Life Is Sweet: Candy consumption and longevity' by I-M Lee and others, in British Medical Journal, vol 317 (4 December 1998), pages 1683-1684. http://bmj.bmjjournals.com/ .. |
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(January 2001, resources updated March 2005)
