Written by Chrystal Moulton, Science Writer. Cocoa polyphenol is associated with reduced fasting blood glucose, LDL and total cholesterol, as well as systolic and diastolic blood pressure.
Cocoa has beneficial effects on the cardiovascular system due to its polyphenolic content1,2. Research has demonstrated positive effects on blood pressure, blood lipids, insulin resistance, and endothelial and platelet function3. However, few studies have explored the impact of cocoa consumption on cardiometabolic risk factors such as body weight, BMI, blood pressure, lipid profile, and anthropometric measures. In the current study, research is conducted a meta-analysis of randomized controlled trials to assess whether dietary coca consumption had any effect on cardiometabolic risk markers4.
Researchers selected randomized controlled trials based on a framework eligibility criterion as follows:
- Study: only randomized controlled trials
- intervention: cocoa extracts supplement or 70% cocoa dark chocolate for more than four weeks
- Comparison: placebo or less than 70% cocoa white/ milk chocolate
- Population: healthy individuals or individuals diagnosed with dyslipidemia, type 2 diabetes, myocardial infarction or stroke, or arterial hypertension; overweight or obese; 18 years or older
- Outcomes: indicators of central obesity specifically BMI, body weight or waste circumference; fasting blood glucose and HbA1C; total cholesterol, triglycerides, LDL, and HDL; systolic and diastolic blood pressure
Subgroup analysis was done to compare healthy versus unhealthy individuals with cardiometabolic risk factors. Primary outcomes were calculated based on baseline data and post intervention data for body weight, waist circumference, BMI, HDL and LDL, triglycerides, total cholesterol, HbA1C, blood glucose, and systolic and diastolic blood pressure. Authors of selected studies were contacted to obtain specific data represented in their selected studies. Studies were excluded if they were found to be duplicates, had inconsistency in data, and presented the wrong expected outcomes. The strength of the evidence was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) tool. This step was done once data extraction was completed from all the selected studies. Researchers also analyzed the heterogeneity of the data using Egger’s test. Summary estimates were presented as mean differences.
A total of 31 studies was used in the final analysis with a total number of participants equaling 1,986 [1,110 in the intervention group and 876 in the control]. The average duration of the intervention was 12 weeks [range: 4-24 weeks]. The amount of cocoa used in the intervention ranged from 1.4-50g. Assessment of the effect of cocoa consumption on anthropometric measures showed No effect was observed for BMI and inconsistency in waist circumference. Meta-regression analysis revealed that in the intervention group baseline BMI was an effect modifier with a modification effect of 77.88% (P=0.034). In other words, every 1.0 kg/m2 increase in BMI was correlated with a 0.14 kg/m2 reduction in BMI in the cocoa intervention group. Analysis of cocoa consumption on the effect on lipid profile demonstrated a significant reduction in total cholesterol (-8.35mg/dL). Subgroup analysis comparing healthy versus unhealthy participants showed a total cholesterol reduction of -7.11mg/dL in unhealthy participants and -7.37mg/dL in healthy participants. However, there was no difference in the effect size between these groups (P=0.959). Further analysis showed that the effect may have been correlated with daily polyphenol intake above a median of 369.7mg. A significant mean difference of -13.37mg/dL was observed for triglycerides. No effect was also observed for HDL cholesterol. Potential effect modifiers were not observed for LDL, HDL, and total cholesterol. However, for triglycerides, baseline BMI (61.82%, P=0.025), age in the intervention group (77.58%, P=0.001) and age in the control group (78.10%, P=0.001) demonstrated strong modifying effect. For every 1.0 kg/m2 increase in BMI, triglycerides decreased by 3.06mg/dL. Also, for every one-year increase in a participant’s age there was an increase of 0.84mg/dL in triglycerides. Cocoa consumption effect on glycemic profile showed a significant reduction in blood glucose (-4.91mg/dL) and fasting blood glucose (-4.57mg/dL) among unhealthy individuals. No effect was observed for HbA1C. Further analysis showed this effect was observed when polyphenol intake was above the median 479.0mg. Researchers did not find potential effect modifiers for glycemic profile. Cocoa consumption showed -2.52mmHg reduction in systolic blood pressure and -1.58mmHg reduction in diastolic blood pressure. Subgroup analysis revealed the reduction in systolic blood pressure of -2.72mmHg in unhealthy participants with no effect in healthy participants. However, a significant reduction in diastolic blood pressure by -1.59 mmHg was observed in the healthy group while no effect was observed in the unhealthy group. Polyphenolic intake above the median of 432.2mg/d demonstrated reductions in both systolic and diastolic blood pressure. Baseline systolic blood pressure was found to be a potential effect modifier of systolic blood pressure values in the intervention group (72.47%, P=0.001) and the control group (48.18%, P=0.007). No effect modifier was observed for diastolic blood pressure. For every increase of 1.0mmHg of systolic blood pressure there was a 0.27mmHg reduction in the intervention group and is your 0.24 mmHg reduction in the control group. Risk of bias analysis showed some concerns across 22 articles and the GRADE tool analysis demonstrate moderate quality of outcomes.
Overall, researchers found that cocoa consumption based on polyphenol intake is associated with reduced fasting blood glucose, LDL and total cholesterol, as well as systolic and diastolic blood pressure. These results suggest a protective effect of cocoa polyphenols on cardiovascular risk factors. Additional studies will be needed to verify these results.
Source: Arisi, Tainah OP, Diego Silveira da Silva, Elana Stein, Camila Weschenfelder, Patrícia Caetano de Oliveira, Aline Marcadenti, Alexandre Machado Lehnen, and Gustavo Waclawovsky. “Effects of Cocoa Consumption on Cardiometabolic Risk Markers: Meta-Analysis of Randomized Controlled Trials.” Nutrients 16, no. 12 (2024): 1919.
© 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/
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Chrystal Moulton BA, PMP, is a 2008 graduate of the University of Illinois at Chicago. She graduated with a bachelor’s in psychology with a focus on premedical studies and is a licensed project manager. She currently resides in Indianapolis, IN.
References:
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- Rudra A, Arvind I, Mehra R. Polyphenols: Types, sources and therapeutic applications. Int J Home Sci. 2021;7(3):69-75.
- Corti R, Flammer AJ, Hollenberg NK, Lüscher TF. Cocoa and cardiovascular health. Circulation. Mar 17 2009;119(10):1433-41. doi:10.1161/circulationaha.108.827022
- Arisi TOP, da Silva DS, Stein E, et al. Effects of Cocoa Consumption on Cardiometabolic Risk Markers: Meta-Analysis of Randomized Controlled Trials. Nutrients. Jun 18 2024;16(12)doi:10.3390/nu16121919
