Chocolate is Delicious and Nutritious but Don't Fall for the Sweetness

For many people with a sweet tooth it would be a dream prescription: take a daily dose of chocolate to be healthy. Alas, it is only a dream for now, but EU-funded research has found that some of the compounds in cocoa, the basic ingredient used to make chocolate, have clear benefits even for healthy people.

The crucial components are flavanols – a group of bioactive plant constituents found in wine and tea, as well as in apples and pears, and which are most abundant in the cocoa bean. 

The three-year FLAVIOLA research project studied cocoa flavanols and found some very positive results, said Dr Christian Heiss, of the cardiology and angiology department at Heinrich Heine University in Düsseldorf, Germany, which coordinated the biomedical research.

Some cocoa or chocolate for dessert, especially when it is rich in flavanols, can also be part of a healthy diet.

Professor Malte Kelm, scientific director of the FLAVIOLA project.

‘We found that flavanols can improve several parameters of cardiovascular health – even in healthy people,’ he said. ‘The potential for primary prevention is there.’

The research consortium included global food manufacturer Mars, which supported FLAVIOLA by analysing samples and by developing and providing a cocoa flavanol-containing test drink as well as a control drink. The control drink was identical to the test drink with the exception that it did not contain flavanols. The medical researchers then compared the two drinks by assessing their respective effect on cardiovascular functions in healthy people, who had no history of heart problems.

‘We aimed at developing a nutritionally conscious delivery form for cocoa flavanols, because although chocolate is an enjoyable treat, based on its comparatively high caloric content it cannot easily be recommended in the context of cardiovascular health,’ said Professor Malte Kelm, scientific director of the FLAVIOLA project.

The researchers observed that study participants who consumed the cocoa flavanol-containing drink experienced cardiovascular improvements. These effects could be demonstrated in healthy men and women ranging from 25 to 65 years old.

Blood pressure

The results were particularly positive with regard to lowering the blood pressure of older people, reducing some of the age-related stiffness in arteries and blood vessels that even in healthy people gradually means an increase in the effort required by the heart to pump blood around the body.

‘We observed that the blood vessels of people on a flavanol-rich diet work better – they get more flexible and dilate more easily. So their capacity to allow healthy blood flow increases and blood pressure decreases,’ Dr Heiss said. ‘Flavanol intake seems also to help to maintain other cardiovascular functions that generally decrease with age.’

While the FLAVIOLA consortium found no direct effect of flavanols on cardiac function, Dr Heiss said that it would be worthwhile studying if the lower blood pressure and improved vascular function could ultimately benefit the heart itself.

The project finished last year, and it’s now up to Mars to decide whether to use the findings to develop a commercial product.

Dr Hagen Schroeter, director of fundamental research into flavanols and health at Mars, said FLAVIOLA demonstrated meaningful cardiovascular benefits and safety for the prototype in the study, adding: ‘We look forward to being able to deliver in the near future consumer-ready cocoa flavanol-containing products that are palatable, nutritionally sound, and that support human health as well as meet all regulatory requirements in Europe.’

The outcomes of the FLAVIOLA study also support the value of carrying out a longer, large-scale investigation of patients with heart problems, as the original studies focused on a healthy population in the context of nutrition.

While the researchers are convinced of the healthy effects of cocoa flavanols, they are cautious about how to ensure these are consumed in the most beneficial way.

Fresh cocoa or cocoa made using flavanol-preserving technologies may contain constituents important for cardiovascular well-being, but these benefits can be lost through traditional cocoa processing, which greatly reduces the flavanol content.

Adding high calorie ingredients such as sugar to make cocoa more palatable also has wider health implications. And simply listing flavanol content in food does not guarantee it is bioactive and that there is enough to have the desired effect.

‘Recommending that everybody eat a significant amount of chocolate every day is not a nutritionally sound option,’ said Professor Marc Merx, coordinator of the FLAVIOLA project. ‘Chocolate should be enjoyed as a treat, but not viewed as an optimal daily source of flavanols.’

Apple skins

FLAVIOLA consortium partners based at the University of Reading, UK, found the major source of flavanols in the normal diet of most Europeans was the skin of apples, and tea. But the average flavanol intake, even in the highest consuming countries, was found to be below the level investigated in most dietary intervention studies to date.

So the proverb ‘an apple a day keeps the doctor away’ has not been displaced quite yet.

‘The flavanol-rich diet is still under development,’ said Prof. Kelm. ‘Until new cocoa flavanol-containing products are available in stores, I guess the best current recommendation would be to eat lots of fruit and vegetables, and to drink a couple of cups of tea. And some cocoa or chocolate for dessert, especially when it is rich in flavanols, can also be part of a healthy diet.’

• This article first appeared in Horizon Magazine in April 2014