I am frequently asked whether a particular sort of food is good or bad for you. It's a question I dread as it usually involves a long winded explanation about context, frequency, portion size and what else you eat - food isn't simply good or bad. Chocolate is definitely one of those foods. As vices go, I would say it is one of the better ones -- certainly versus alcohol, cigarettes and Dunkin' Donuts.

Chocolate is made from the seeds of the cacao tree native to tropical areas of South America. It certainly possesses some beneficial ingredients, the most significant of which are polyphenols. These are potent antioxidants found in far greater concentrations in cocoa powder compared to other foods such as onions, apples and green tea. Such antioxidants help prevent the hardening of bad cholesterol (LDL) in the arteries, thereby protecting the heart. A study in the Journal of the American Medical Association (JAMA) this summer showed that these polyphenols also help lower blood pressure. Positive news indeed, but it should be stressed that participants were fed only 30 calorie's worth of chocolate per day, roughly one square, so no excuse for a choccy binge.

The reported mood-altering effects of chocolate may be due to small constituent amounts of caffeine and a similar compound - theobromine, which have mild stimulatory effects. Interestingly, theobromine is what makes chocolate poisonous to some animals, especially dogs, who are unable to metabolize it. As little as 50g of chocolate can be toxic for a small dog. Another natural compound found in chocolate is phenylethylamine, and it is this that has given chocolate a reputation as an aphrodisiac. It is chemically similar to amphetamine and is supposedly produced by the brain when one falls in love.

The main problem with chocolate is the sugar and saturated fat and some studies have suggested that it is these two elements and not the cocoa itself which boost production of serotonin, a feel good hormone in the brain. Fortunately, the saturated fat in good quality chocolate is stearic acid, which does not have the same adverse effects on cholesterol that other saturated fats do.

The Glycemic Index (GI) of chocolate, which measures the rate at which food raises blood sugar levels, is fairly positive at around 50-60, which puts it on par with an apple. Of course this has to be compared on a calorie basis, so one whole apple (150g) will raise blood sugar levels by the same amount and rate as around 1.5 squares of chocolate. For the healthiest possible chocolate fix, go for a few squares of dark chocolate containing 70% or more cocoa solids.

Chinese-manufactured chocolate is certainly not something to write home about. However, since the end of last year, regulations have stipulated that real cocoa butter, rather than cheaper and less healthy replacements, be used. It is clearly not a traditional part of the Chinese diet, with chocolate consumption per year being only around 100-150g per person. Nevertheless popularity has been increasing massively. Demand increased to 9,000 tons in 2000, representing a 90% increase from the previous year. Still, there is a clear fundamental difference that leads to my 3pm cravings being satisfied by a few squares of Lindt while my Chinese colleagues opt for foil wrapped dried meat.

This nutrition-related column is written by Nina Lenton, a qualified dietitian living in Beijing and working at Bayley and Jackson Medical Center. Contact her at nina.lenton@ikang.com

(China Daily 11/28/2007 page14)