Media release from Science Media Centre
 
High levels of chocolate consumption might be associated with a one third reduction in the risk of developing heart disease, according to a new study. However the authors and independent experts urge caution in the interpretation of the results.     
 
The research, to be published today in the British Medical Journal, analysed data from previous studies that examined chocolate consumption and various cardiovascular and metabolic outcomes.

The findings confirm results of existing studies that generally agree on a potential beneficial link between chocolate consumption and heart health. However, the authors stress that further studies are needed to test whether chocolate actually causes this reduction or if it can be explained by some other unmeasured (confounding) factor.

A full press release and a copy of the study is available in the SMC Resource Library.  

The Science Media Centre contacted New Zealand experts for comment. Feel free to use these quotes in your stories. To talk to a local expert, please contact the SMC. 

Dr Alexandra Chisholm, Senior Lecturer / Research Dietitian, Department of Human Nutrition, University of Otago said:
 

"The article does not differentiate between types of chocolate whereas the interventions & studies looking at mechanisms of action use high cocoa solids chocolate. 

"As these are cohort, case-control, and cross sectional studies they can not show causality only indicate possible areas of further research. Further the authors state "Large
variation was observed between these seven studies for measurement of chocolate consumption, methods, and outcomes evaluated."   

"This is a problem as beneficial effects may be related to frequency /infrequency of consumption & there may also be a gender specific effects which, were not able to be measured in this study.

"The authors selected studies in which "chocolate consumption was assessed by a validated tool" however from this food frequency questionnaire (FFQ) it would appear that they used "a single item from the food frequency questionnaire that asked about consumption of chocolate bars, snacks, or pieces" (this is unclear) thus other possibly confounding dietary factors would not have been captured.   Did those in the highest chocolate consumption category have a better overall dietary pattern?  

"The  FFQ included chocolate drinks which may have indicated a higher consumption of milk. Some other dietary factors have been adjusted for (Table 2) but one wonders how these were measured.  One study reviewed (Mink et al 2007) measured flavonoid intake & only adjusted for energy consumption so one could assume that chocolate was only one item measured.

"The authors "necessary cautions" and relatively cautious conclusions are appropriate however it is not clear that reducing the amount of fat & sugar in commercially available chocolate will transform it into a more beneficial food.  However the use of minimally processed, higher cacao products in developing countries may have some merit."

The following quotes are from our friends at the UK Science Media Centre.

Prof Tom Sanders, Professor of Nutrition & Dietetics and Head of the Diabetes & Nutritional Sciences Division, School of Medicine, King's College London, said:
 
"The problem on chocolate consumption is underreporting by overweight individuals; they under report food intake, especially forbidden foods such as chocolate. There is a chocolate gap - more chocolate is sold than people own up to consuming.

"Cocoa butter, although a rich source of saturated fatty acids, does not raise cholesterol much because the major saturated fatty acid in it is stearic acid, which neither raises nor lowers cholesterol. The evidence regarding chocolate and blood pressure is mixed, with a recent study showing that cocoaflavonoids increase blood pressure.
 
"The main problem with chocolate is overindulgence and calories. A little bit of chocolate is OK but the mega-slabs offered cheaply are fuelling obesity in the overweight."
 

Victoria Taylor, Senior Heart Health Dietitian at the British Heart Foundation, said:

"Evidence does suggest chocolate might have some heart health benefits but we need to find out why that might be.

"We can't start advising people to eat lots of chocolate based on this research. It didn't explore what it is about chocolate that could help and if one particular type of chocolate is better than another.
 
"If you want to reduce your heart disease risk, there are much better places to start than at the bottom of a box of chocolates. You can still eat chocolate as part of a balanced diet but moderation is key because this sweet treat is usually packed with saturated fat and calories."

Catherine Collins, Dietician at St George's Healthcare NHS Trust, said:
 
"Most chocolate we eat is milk chocolate, which in this country is different to continental milk chocolate in the amount of vegetable versus milk fat we blend with cocoa to give it its '30%/ 45% cocoa solids" definition.  Also, white chocolate is a totally different product altogether so can't be compared with brown chocolate with regards to flavonoid content.  Cocoa butter does not appear to raise cholesterol, due to it stearic and oleic acid contents, but of course the sugar content of the final item could raise triglycerides but the results seem to suggest any clinical consequence of this is negligible.

"This paper doesn't really say eat chocolate to improve heart health - nor do the authors conclude this either.  What they seem to say is, those who don't deny themselves a sweet treat of choc - white or brown - have better cardiovascular outcomes.  I do feel that the perceived relaxing effect of chocolate (which is recorded in studies as being as soon as the taste and 'mouthfeel' of choc is experienced, before the product has hit the intestine and contributed to blood levels of sugar/serotonin whatever) is a contributor - perhaps akin to modest alcohol consumption - a relaxing treat, perceived as a 'de-stressor' and a food whose cost base is so low it's affordable by virtually all. 

"In terms of UK chocolate, it has to be based on relaxation rather than nutritional content, as our fancy-and-filled product ranges (think Crunchie, Mars bar, Topic, Turkish Delight) contain such little actual chocolate per unit, and what is there is mainly milk choc with low cocoa solids, that this cannot be solely attributed to cocoa flavonoids alone.  For more information see http://www.cacaoweb.net/nutrition.html

"So, it's better for general health to relax and enjoy all foods, rather than be one of the food fascists I regularly meet who will 'eat four squares of high quality organic dark chocolate and three brazil nuts a day' for the heart and selenium benefits respectively.  (Perhaps a chocolate brazil would do the same trick!)"
 
Study 'Chocolate consumption and cardiometabolic disorders: systematic review and meta-analysis', Adriana Buitrago-Lopez et al, BMJ 2011;343:d4488 doi: 10.1136/bmj.d4488 will be published in the BMJ at 09.10am UK time Monday 29 August 2011.