2017 Cocoa Research Update

Insulin Resistance
A current area of research interest is how cocoa and chocolate consumption may affect blood sugar metabolism.

A recent study led by Ala’a Alkerwi from the Luxembourg Institute of Health (Strassen, Luxembourg) looked at the link between chocolate consumption and insulin resistance in 1153 adults aged 18-69 residing in Luxembourg.(5) A food frequency questionnaire was used to assess chocolate intake, while blood glucose and insulin levels were assessed to calculate the measure of insulin resistance known as HOMA-IR. In addition, liver function markers, including serum γ-glutamyl-transpeptidase (γ-GT), serum aspartate transaminase (AST), and serum alanine transaminase (ALT), were assessed. In general, the researchers noted that consumers of chocolate were more likely to be younger, physically active, affluent people with higher education levels and fewer chronic health issues compared to those who didn’t consume chocolate.

After excluding those individuals who were on antidiabetic drugs, higher chocolate consumption was associated with lower insulin resistance (calculated as HOMA-IR), lower serum insulin levels, and lower liver enzymes, including γ-GT and ALT, suggesting that chocolate consumption may improve liver enzymes and protect against insulin resistance, a risk factor for cardiometabolic issues.

References:
5. Alkerwi A et al., “Daily chocolate consumption is inversely associated with insulin resistance and liver enzymes in the Observation of Cardiovascular Risk Factors in Luxembourg study,” The British Journal of Nutrition, vol. 115, no. 9 (May 2016): 1661-1668

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Heart Failure
The cardiovascular health benefits of cocoa stem from multiple potential mechanisms. A large study conducted by researchers from Harvard Medical School (Boston, MA) evaluated the association of chocolate consumption with the incidence of heart failure. In this prospective cohort study including 31,917 Swedish men aged 45-79, researchers recruited individuals with no history of myocardial infarction, diabetes, or heart failure at baseline and assessed chocolate consumption using food frequency questionnaires.(6) The men were followed between January 1, 1998, and December 31, 2011, and researchers monitored hospitalization for heart failure as well as mortality via records in Swedish registries.

Interestingly, when compared to those with no chocolate intake, individuals consuming moderate levels of chocolate (1-3 servings per month, 1-2 servings per week, and 3-6 servings per week) had progressively decreased risk of heart failure. Notably, however, those consuming more than one serving of chocolate per day were shown to have an increased risk of heart failure in the cohort. While additional research is needed to clarify the findings, the authors suggest that moderate chocolate consumption may be beneficial for heart-failure risk, while higher consumption may in fact increase the risk of heart failure. 

References:
6. Steinhaus DA et al., “Chocolate intake and incidence of heart failure: Findings from the Cohort of Swedish Men,” American Heart Journal, vol. 183 (January 2017): 18-23

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Arterial Health
Furthering the potential cardiovascular health benefits of cocoa products, researchers led by Georgina Crichton from the University of South Australia (Adelaide, Australia) evaluated the relationship between dietary chocolate intake and arterial stiffness in men and women with an average age of 61.(7) In the prospective study including 508 individuals regardless of health status, researchers evaluated food frequency questionnaires at baseline to assess frequency of chocolate consumption.

Approximately five years later, researchers assessed pulse-wave-velocity measurements, an indicator of arterial stiffness. Higher pulse wave velocity is associated with greater arterial stiffness, while lower values indicate better arterial flexibility.

Researchers found that dietary chocolate intake was significantly associated with pulse wave velocity; however, the association was non-linear. Pulse wave velocity was highest in those with no or rare dietary consumption of chocolate. Pulse wave velocity was lowest in those consuming moderate amounts of chocolate (an average of once per week). Interestingly, those individuals consuming chocolate more than once per week on average also had higher pulse-wave-velocity values. The findings further support the concept of moderate chocolate intake being heart healthy, while higher intakes are associated with worsening of arterial health parameters.

References:
7. Crichton GE et al., “Relation of habitual chocolate consumption to arterial stiffness in a community-based sample: preliminary findings,” Pulse, vol. 4, no. 1 (July 2016): 28-37

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Skin Aging
Since cocoa is rich in flavanols and other compounds with antioxidant activity, researchers have been investigating the effects of cocoa intake on skin-health parameters. In a recent double-blind, placebo-controlled study in Korean women (aged 43-86) with signs of photo-aging, Hyun-Sun Yoon and colleagues from Seoul National University (Seoul, Korea) looked at the effects of daily cocoa supplementation (320 mg total flavanols/day) for 24 weeks on signs of skin aging, including wrinkles, skin moisture, and elasticity. The researchers assessed wrinkles, skin elasticity, and hydration at baseline and at 12 and 24 weeks.

Skin-roughness values changed significantly at 24 weeks in the cocoa group versus placebo (decrease of 8.7 versus 1.3 percentage points, respectively). Overall skin elasticity also improved significantly in the cocoa group versus placebo at both 12 and 24 weeks. However, no significant differences were noted in measures of skin hydration. Based on the results seen, the researchers noted that the cocoa supplement had beneficial effects on facial wrinkles and elasticity and may contribute to the prevention of some signs of photo aging in women.(4)

References:
4. Yoon HS et al., “Cocoa flavanol supplementation influences skin conditions of photo-aged women: a 24-week double-blind, randomized, controlled trial,” The Journal of Nutrition, vol. 146, no. 1 (January 2016): 46-50

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