Can Chocolate Prevent Diabetes?

Probably not.

I quite literally had to go out and buy chocolate just to get through this piece. The pictures, they are too good. Photo by Heather Barnes on Unsplash

Chocolate is one of those wonderful foods that we all really want to be good for us. Like red wine and even ice cream, chocolate is something that we all kind of know is probably bad for us but would love to be proven wrong about. How great would it be if you could make yourself healthier by eating just a bit of the sweet, rich treat?

According to recent headlines, there’s cause for celebration. A range of publications have been celebrating the news that chocolate, and dark chocolate in particular, may reduce your risk of diabetes. Good news for those of us who occasionally like to indulge in one of the most delicious foods that humanity has ever discovered.

Unfortunately, the data is very unconvincing. It’s possible that dark chocolate is good for you, but realistically it’s incredibly unlikely. I’d stick to having the rare chocolate treat rather than filling up your shopping trolley with the sweet stuff regularly.

Let’s look at the data.

The Study

The newest piece of research on chocolate is a large observational trial looking at three cohorts of US health professionals. These are the Nurses Health Study, the Nurses Health Study 2, and the Health Professionals Follow-up Study. All three studies had a similar protocol - the study authors asked people a range of questions about the food that they ate when the study was started, and then once every few years after that. These studies followed-up people for over a decade, and recorded all of their health outcomes such as heart disease and diabetes. In this particular paper, the authors took these massive cohorts of 10,000s of people and looked at their long-term risk of developing diabetes based on how much chocolate they said they ate during the study.

This paper is, as far as observational studies go, decent. The authors considered things like confounding factors that could cause both chocolate consumption and diabetes, and controlled for them in a statistical analysis. The numbers were very big - nearly 200,000 people in the main analysis - which lends some strength to the study. The authors also conducted a wide range of sensitivity analyses, looking at some of the things that might disprove their theory.

The results were interesting - neither overall chocolate consumption nor milk chocolate consumption had any relationship with diabetes. However, people who said they ate more dark chocolate were less likely to get diabetes over the course of the study.

Pictured: Prevents…diabetes? Photo by Tetiana Bykovets on Unsplash

Specifically, after about 15 years of follow-up, about 40 in 10,000 people who said that they ate little to no dark chocolate got diabetes in this study. For people who ate at least one serving of dark chocolate a day, that dropped to 25 in 10,000, or an absolute reduction of 0.15% in risk of diabetes. The authors say that this reduction in risk was likely due to specific compounds present in high quantities in dark chocolate called flavanol.

However, I’m not running out to go buy a bar of Lindt dark just yet (well, I am, but not for health reasons). There’s no good reason to believe that dark chocolate actually has an impact on diabetes, despite these rosy sounding findings.

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