Is chocolate really an ally in diminishing the risk of type 2 diabetes?

Sweet news came recently from a study that looked at chocolate consumption and the risk of type 2 diabetes.Canadians eat an average of 6.4 kg of chocolate a year, according to data from the Inter-American Institute for Cooperation on Agriculture and reported in Canadian Grocer.Chocolate is one of the foods with the highest flavanol content, and it is already known that consumption of dietary flavonoids—which have antioxidant, anti-inflammatory and vasodilatory effects—promotes cardiometabolic health, memory in particular. But the association between chocolate consumption and the risk of type 2 diabetes remained controversial due to inconsistent results in observational studies focusing on total chocolate consumption. The recent COSMOS study, for example, found that cocoa flavanol supplements did not affect the risk of type 2 diabetes.So researchers at Harvard University's TH Chan School of Public Health set out to prospectively examine the associations between dark, milk and overall chocolate consumption, and the risk of type 2 diabetes. Their findings were published in the British Medical Journal.A novel analysis of chocolate subtypesThe researchers used data from three large prospective cohort studies—the Nurses' Health Studies (NHS), the Nurses' Health Study II (NHSII) and the Health Professional Follow-up Study (HPFS)—between 1986 and 2021. A total of 192,208 participants were included in the analysis of total chocolate consumption, and 111,654 in the analyses of chocolate subtypes. Their overall followup spanned 30 years, from 1986 to 2021.Analyses of total chocolate consumption began in 1986 for the NHS and HPFS, and in 1991 for NHSII. Analyses of chocolate subtypes began in 2006 for the NHS and HPFS, and in 2007 for NHSII—questions on specific chocolate consumption subtypes, in particular, “How often do you consume milk chocolate (bar or packet),” and, “How often do you consume dark chocolate,” were added to the food frequency questionnaires from these dates.Chocolate subtypesThe researchers used data from three large prospective cohort studies—the Nurses' Health Studies (NHS), the Nurses' Health Study II (NHSII) and the Health Professional Follow-up Study (HPFS)—between 1986 and 2021. A total of 192,208 participants were included in the analysis of total chocolate consumption, and 111,654 in the analyses of chocolate subtypes. Their overall followup spanned 30 years, from 1986 to 2021.Analyses of total chocolate consumption began in 1986 for the NHS and HPFS, and in 1991 for NHSII. Analyses of chocolate subtypes began in 2006 for the NHS and HPFS, and in 2007 for NHSII—questions on specific chocolate consumption subtypes, in particular, “How often do you consume milk chocolate (bar or packet),” and, “How often do you consume dark chocolate,” were added to the food frequency questionnaires from these dates.Study detailsThe adults who were followed did not have prevalent diabetes, cardiovascular disease or cancer at baseline. Other initial exclusions were extreme total energy intake and missing data on chocolate consumption or body weight.All participants reported their dietary habits, diabetes status and body weight over time.Diet was assessed every four years using a semi-quantitative food frequency questionnaire. Participants indicated their average frequency of consumption of a standard food portion (e.g., one chocolate bar/pack or 1 oz.) over the previous year, choosing from nine levels ranging from “never, or less than once a month” to “≥ 6 per day.”Information on participants' personal (race/ethnicity, body weight, waist circumference) and lifestyle factors (healthy eating, physical activity, smoking status, alcohol consumption, multivitamin use), as well as diseases or medical conditions (menopausal status, oral contraceptive use, hypertension, hypercholesterolemia and family history of diabetes), was collected every two years.Read: Quiz: How much do you know about chocolate?In the primary analyses, the researchers used Cox proportional hazards models to estimate hazard ratios and corresponding 95% confidence intervals (CIs) for the association between total, dark and milk chocolate consumption levels and T2D risk. They also classified regular chocolate consumption into four groups of levels, including never or < 1 portion/month (baseline), 1 portion/month to < 1 portion/week, 1 to 4 portions/week and ≥ 5 portions/week. During longitudinal follow-up, 18,862 participants reported being diagnosed with T2DM. “No significant association was observed between total chocolate consumption and T2DM risk in the pooled dataset,” the researchers reported. Study findingsAfter adjusting for lifestyle and dietary risk factors, however, they found that participants who consumed ≥ 5 servings/week of any chocolate had a 10% lower relative risk of T2DM (95% CI 2% to 17%; trend P = 0.07) compared with those who never or rarely consumed chocolate.For analyses by chocolate subtypes, 4771 people with type 2 diabetes were identified during longitudinal follow-up. Participants who consumed ≥ 5 servings/week of dark chocolate had a significantly lower rate of T2DM by 21% (5% to 34%) compared with those who never or rarely ate dark chocolate. A significant 3% (1% to 5%) reduction in T2D risk was observed for each portion/week of dark chocolate consumption.“The results of the present study show that higher consumption of dark chocolate, but not milk chocolate, is associated with a lower risk of type 2 diabetes,” the researchers wrote.However, consumption of milk chocolate was statistically significantly associated with greater weight gain—a risk factor for type 2 diabetes—but increased consumption of dark chocolate was not. “Further research, including randomized controlled trials in middle-aged participants of longer duration, is needed to confirm these findings,” the researchers concluded.View the study: Chocolate intake and risk of type 2 diabetes: prospective cohort studies

Is chocolate really an ally in diminishing the risk of type 2 diabetes?

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