Dark chocolates linked to lower T2D risk

Eating dark chocolates may help reduce the risk of type 2 diabetes (T2D), whereas milk chocolates tend to promote long-term weight gain, as shown in a study.

Researchers prospectively analysed the association between chocolate consumption and T2D risk using data from the Nurses’ Health Study (NHS; 1986‒2018), NHS II (1991‒2021), and Health Professionals Follow-up Study (HPFS; 1986‒2020).

A total of 192,208 participants without T2D, cardiovascular disease, or cancer were included in total chocolate analyses at study baseline. Of these, 111,654 were analysed for T2D risk by intake of chocolate subtypes, assessed from 2006 in NHS and HPFS and from 2007 in NHS II.

Follow-up questionnaires were used to identify patients with self-reported incident T2D, confirmed through a validated supplementary questionnaire. The research team estimated hazard ratios (HRs) and 95 percent confidence intervals (CIs) for T2D according to chocolate consumption via Cox proportional hazards regression.

Dark chocolate

Of the participants, 18,862 people were found to have incident T2D during 4,829,175 person-years of follow-up. Consumption of ≥5 servings/week of any chocolate resulted in a 10-percent (95 percent CI, 2‒17; p=0.07 for trend) lower rate of T2D than no consumption after adjusting for personal, lifestyle, and dietary risk factors. [BMJ 2024;387:e078386]

When analysing chocolate subtypes, incident T2D was noted in 4,771 participants. Those who consumed ≥5 servings/week of dark chocolate benefitted from a 21-percent (95 percent CI, 5‒34; p=0.006 for trend) reduced T2D risk. No significant associations were seen for consuming milk chocolate.

A linear dose-response association was observed between dark chocolate intake and T2D risk (p=0.003 for linearity), with a significant 3-percent (95 percent CI, 1‒5) risk reduction for each serving/week of dark chocolates. On the other hand, milk chocolate consumption showed a positive association with weight gain.

“Our study’s finding that intake of total chocolate was statistically significantly associated with lower risk of diabetes was in line with previously published studies,” the researchers said.

In the Physicians’ Health Study, results showed that consuming ≥2 servings/week of total chocolate correlated with a 17-percent lower risk of T2D in 18,235 participants during a median follow-up of 9.2 years. [Am J Clin Nutr 2015;101:362-367]

Furthermore, the Multiethnic Cohort Study reported a 19-percent reduced T2D risk when consuming chocolates ≥4 times/week compared with a lower frequency of consumption, while the Main-Syracuse Longitudinal Study found a 91-perent higher risk for those who never or rarely eat chocolates. [Eur J Clin Nutr 2019;73:671-678; Appetite 2017;108:263-269]

Mechanism

“Dark chocolate, with a higher cocoa content than milk chocolate, may lower the risk of T2D through various mechanisms,” the researchers said. [J Agric Food Chem 2006;54:4057-4061]

“It has been suggested that bioactive compounds in cocoa, such as flavan-3-ols and their monomeric form, epicatechin, mitigate risk of T2D by improving insulin sensitivity, protecting pancreatic β cells from oxidative stress, [and] lowering pro-inflammatory cytokines,” they added. [J Clin Biochem Nutr 2011;48:63-67; Int J Mol Sci 2021;22:1509; Oxid Med Cell Longev 2012;2012:906252]