Harvard study claims chocolate can help prevent Type 2 diabetes

In a large study conducted by Harvard T.H. Chan School of Public Health, researchers examined the relationship between chocolate consumption and the risk of developing Type 2 diabetes among over 190,000 participants. The study, published in The BMJ, followed participants for a period of up to 34 years, gathering data on their chocolate intake through detailed diet questionnaires completed every four years. Around 18,862 cases of Type 2 diabetes were documented during the study period, highlighting the potential significance of diet in disease prevention. The results showed that those who consumed dark chocolate—defined as having at least 70% cocoa—at least five times a week demonstrated a 21% lower risk of diabetes compared to individuals who consumed dark chocolate infrequently. Conversely, participants who primarily consumed milk chocolate did not show the same protective benefits. In fact, the analysis revealed that milk chocolate consumers were more likely to gain weight over the study's duration, pointing to an unfavorable association with diabetes risk. While the findings suggest a correlation between dark chocolate consumption and reduced diabetes risk, experts have cautioned that the study does not establish a direct cause-and-effect relationship. Other health behaviors among dark chocolate consumers, such as higher physical activity levels or healthier overall diets, could also contribute to the observed differences in diabetes risk. The study predominantly comprised well-educated, mostly white participants, which raises questions about the generalizability of the results to diverse populations. Dark chocolate contains beneficial compounds known as flavonoids, which are thought to have antioxidant and anti-inflammatory effects. These compounds could protect insulin-producing cells in the pancreas. Although some small-scale studies have indicated that cocoa can reduce blood pressure and improve insulin sensitivity—both important factors in diabetes prevention—the overall body of research remains inconclusive. The authors advocate for more randomized controlled trials to replicate their findings and further understand how specific chocolate types may influence metabolic health.