Can the consumption of cocoa and red berries improve cardiovascular biomarkers?

By Bhavana KunkalikarReviewed by Lily Ramsey, LLMMay 16 2023

In a recent study published in the Nutrients journal, researchers explored the potential benefits of consuming cocoa and red berries to improve cardiovascular biomarkers.

Study: Regular Consumption of Cocoa and Red Berries as a Strategy to Improve Cardiovascular Biomarkers via Modulation of Microbiota Metabolism in Healthy Aging Adults. Image Credit: NatashaBreen/Shutterstock.com

Background

Cardiovascular diseases (CVD) are the second leading cause of mortalities globally, with most cases occurring in individuals over 60, following cancer.

Aging leads to vascular endothelium dysfunction and elevated arterial stiffness and thickening. In addition, aging decreases endothelial nitric oxide synthase (eNOS) activity, which is responsible for producing nitric oxide (NO).

NO is a crucial vasodilator that controls vascular tone and prevents vascular inflammation. Polyphenols found in the human diet have been proven to be effective in fighting the negative effects of aging.

They are particularly useful in preventing cognitive function decline and the onset of cardiovascular disease.

About the study

In the present study, researchers examined how red berry anthocyanins and cocoa flavanols impact cardiovascular biomarkers, including homocysteine, NO, flow-mediated vasodilation (FMD), angiotensin-converting enzyme (ACE), blood pressure, and lipid profile.

The study was a 12-week randomized, single-blind, parallel-group trial. The study involved assigning volunteers to three groups based on their consumed product. Group one consumed a mixture of red berries (RB) at a rate of 5 g/day, while group twp consumed a polyphenol-rich cocoa powder (C) at a rate of 2.5 g/day.

Group three consumed a combination of cocoa and red berries (RB+C) at a rate of 7.5 g/day. Potential candidates for the study were selected from aging adults aged 45 to 85 years old, including men and postmenopausal women. 

Volunteers visited the Human Nutrition Unit at ICTAN-CSIC on three separate occasions to provide samples and data. An eligibility check was conducted through a personal interview during the initial visit. The study's baseline was the second visit, while the 12-week intervention concluded at the third visit.

Various measurements were taken during each visit, including a blood specimen, early morning urine, height, weight, blood pressure, waist circumference, and 24-hour diet records. The team also measured nitric oxide levels in plasma and flow-mediated vasodilation (FMD).

Results

The study found no notable variations between the groups in terms of age, gender, height, or the proportion of smokers at the beginning of the study. The study population had a chronic smoking rate of 20%.

No significant differences were observed between the groups in the concentrations of total serum protein, homocysteine, NO, ACE, and d trimethylamine N-oxide (TMAO) activity. Between visits, the team noted a statistically remarkable increase in FMD values within the cocoa powder cohort and a reduction in TMAO levels post-12-week intervention in the cocoa group.

No significant changes in any of the analyzed features were observed between baseline and 12 weeks concerning any diet.

No significant differences were found between groups in the analyzed parameters at the beginning of the study, similar to the cardiovascular parameters. No notable variations were observed among the groups or visits for any parameters at the endpoint.

After a 12-week intervention, the group that consumed cocoa showed a greater increase in polyphenol levels than the group with RB+C. This resulted in significant differences between the two groups.

A significant increase in polyphenol plasma levels was observed in the C group, while in the RB group, the elevation in total polyphenols was close to significance when examining the differences within the groups.

The 12-week intervention resulted in significant differences in blood chenodeoxycholic acid (CDCA) concentrations among the RB and C groups. The group that consumed the RB mixture showed the largest rise in CDCA concentrations.

Statistically significant differences were only observed in the RB group, where concentrations of DCA increased after the intervention with the RB mixture. A nearly significant difference was also observed in CDCA in the RB cohort, with a notable increase after the intervention.

The study found only significant differences between the isovaleric (ISOV) and caproic (CAP) acids groups. Group C had a higher concentration of ISOV than group RB+C, while group RB had a higher concentration of CAP than group RB+C.

The intervention with food products resulted in a slight boost in all short-chain fatty acids (SCFAs), except for butyric (BUT) in the C and RB+C cohorts.

Red berry anthocyanins consumption resulted in a significant rise in fermentation index A (FIA) ratio in the RB and C groups and a nearly significant elevation in ACE and total SCFAs.

Conclusion

The study findings showed that consuming cocoa flavanols regularly can enhance cardiovascular health by decreasing TMAO and uric acid levels, improving FMD values, and having a correlation with polyphenol levels in serum. Polyphenol levels were found to have a negative correlation with concentrations of TMAO.

Cocoa flavanols and RB anthocyanins enhance gut microbiota metabolism by promoting carbohydrate fermentation, increasing the production of SCFAs. Including more polyphenol-rich foods in one's diet could effectively delay or prevent age-related cardiovascular diseases.

Additional placebo-controlled studies are required to gain a deeper understanding of the mechanisms involved in the possible cardiovascular protective and prebiotic impacts of cocoa flavanols and RB anthocyanins.