Medical Matters: Reading this just after Easter Sunday, many of you will be able to reflect on the joy of eating chocolate in the form of Easter eggs.
All forms of chocolate are associated with mood elevation; however, when it comes to physical health benefits, only dark chocolate cuts the mustard.
Dark chocolate and specifically chocolate with a high cocoa content, contains high levels of chemicals called flavanols. These are antioxidants that are also found in fruit and wine; they are known to protect against damage to cells in the body.
The latest good news for chocolate lovers comes from research published in the American Journal of Clinical Nutrition. Researchers from the University of L'Aquila in Italy carried out an experiment to determine the benefits of white versus dark chocolate. Healthy volunteers were given 100g of dark chocolate daily for 15 days, followed by a "wash out" period of seven days with no chocolate, then a further 15-day period of 100g of white chocolate. Throughout this time, blood tests were taken from each subject in order to measure insulin resistance; blood pressure levels were also monitored.
The results show that insulin resistance was significantly lower when the subjects ate dark chocolate rather than white chocolate. In addition, blood pressure was lower during the two weeks of dark chocolate consumption.
The insulin resistance findings are especially significant. For people with diabetes, it suggests that dark chocolate, eaten in moderation and as part of a balanced low-fat and low-sugar diet, could help increase the sensitivity of cells in the body to insulin. One of the reasons why diabetes develops is that cells become resistant to the effects of insulin, leading to a rise in blood sugar levels.
But the finding could also be significant for a much wider population. Rising obesity levels mean that many of us are at risk of developing a condition called metabolic syndrome. Sometimes referred to as pre-diabetes, the syndrome encompasses several clinical findings; high blood pressure, a raised cholesterol level, and elevated sugar and insulin levels (a sign of insulin resistance).
There is also a link between excess fat distribution around the waist and the likelihood of developing metabolic syndrome. It seems that fat cells located in the abdomen are not dormant in the way that fat in other parts of the body is. It appears that these "belly" fat deposits are active in a metabolic sense and contribute to the development of cardiac problems and diabetes.
Some 18 per cent of the Republic's population is obese, representing a two-thirds increase in the last 15 years. Almost four in 10 of us are overweight. As Kate Holmquist pointed out recently (The Irish Times, March 19th), obesity is both a political and a sociological challenge, costing the State an estimated €370 million a year. The obesity epidemic has huge implications for childrens' health in particular.
The difficult question is: what to do about the problem? It's not as straightforward an issue as the workplace ban on tobacco.Then, there was clear evidence that an individual's second-hand smoke could damage the health of others. Eating food laden with calories and not exercising, while damaging a person's own health, does not directly affect other people. This would seem to limit the State's ability to intervene with legislation.
But an alternative argument, from a broad public health perspective, is that rising levels of obesity will put an intolerable future strain on our health services and that State intervention is justified. Should this intervention be confined to health education and increasing access to healthy food options, or should the food industry be targeted in a way the tobacco industry was, for example by taxation on certain foods? Is it time to consider different levels of social engineering to tackle the problem?
There are no easy answers. Nor does the scientific literature offer much certainty. An editorial in the current issue of the British Medical Journal points out the varying results achieved by improving access to healthy food at retail outlets. The editorial calls for a multidimensional approach that includes changing knowledge about, as well as improving access to, healthy food.
It is a highly complex area and one that needs research and debate rather than precipitate action. In the meantime it seems like a good idea to continue the Easter habit and include moderate amounts of dark chocolate in your diet.
•Dr Muiris Houston is pleased to hear from readers at mhouston@irish-times.ie but regrets he cannot answer individual queries.