Dark chocolate can offer health benefits including reduced risk of type 2 diabetes

Good news for lovers of dark chocolate – and especially during the season of tempting festive treats – as report highlights benefit of consumption as a factor in reduced risk of developing type 2 diabetes.

The results of a new study have reported that participants who consumed at least five ounces of any type of chocolate per week had a 10% lower risk of developing type 2 diabetes compared to those who never or rarely consumed chocolate.

The findings revealed that dark chocolate had an even bigger impact. Study participants who consumed at least five servings of dark chocolate per week showed a 21% lower risk of developing type 2 diabetes.

The research was carried out at Harvard T.H. Chan School of Public Health in Boston, Massachusetts, with the results recently published in the BMJ.

Binkai Liu, doctoral student in the Department of Nutrition and study lead author, said: “Our findings suggest that not all chocolate is created equal.

“For anyone who loves chocolate, this is a reminder that making small choices, like choosing dark chocolate over milk chocolate, can make a positive difference to their health.”

The findings of previous research on the relationship between chocolate and type 2 diabetes have been inconsistent, and few studies had differentiated between chocolate subtypes (e.g. dark versus milk). 

For this latest study, researchers sought to fill this gap using data from the Nurses’ Health Studies I and II and the Health Professionals Follow-up Study. Over the course of more than 30 years and 192,000 adult participants who were free of type 2 diabetes at the study’s outset reported on their food habits, including chocolate consumption, as well as their diabetes status and body weight. By the end of the study period, almost 19,000 of the total participants reported being diagnosed with type 2 diabetes. Of around 112,000 who reported specifically on their dark and milk chocolate intake, nearly 5,000 were diagnosed with type 2 diabetes. 

The researchers also noted a 3% reduction in risk for every serving of dark chocolate consumed per week.

Consumption of milk chocolate, meanwhile, was not associated with a reduction of developing type 2 diabetes. Instead, increased consumption of milk chocolate, but not dark chocolate, was associated with long-term weight gain, a potential contributor to the development of type 2 diabetes.

Qi Sun, associate professor in the Departments of Nutrition and Epidemiology and study corresponding author, said: “We were surprised by the clear split between dark and milk chocolate’s impact on type 2 diabetes risk and long-term weight management.

“Even though dark and milk chocolate have similar levels of calories and saturated fat, it appears that the rich polyphenols in dark chocolate might offset the effects of saturated fat and sugar on weight gain and type 2 diabetes. It is an intriguing difference that is worth exploring more.”

The authors noted that participants’ chocolate consumption was low relative to previously recorded national averages and that the findings may not apply to individuals with very high chocolate consumption. 

In conclusion, researchers added: “Further randomised controlled trials are needed to replicate these findings and further explore the mechanisms.”

Read the report in the BMJ

Read more about type 2 diabetes