Beneficial effects of cocoa and dark chocolate polyphenols on health
Authors: García Leonel Cuamatzin , Hernández Alma Nubia Mendoza 
Published: April 2020

Introduction

Currently, the rediscovery beneficial effects of cocoa and dark chocolate focus on its nutritional value as dietary and therapeutic supplements
,
, associated with its polyphenol content (resveratrol, anthocyanins, flavonols and catechins)
, wich reduce the incidence of cardiovascular diseases
and cancer by deacreasing oxidative stress (antioxidant effect)
,
.

Objective

Search and analyze the evidence in available scientific articles on the effect of dark chocolate consumption on health.

Methodology

A literature review of various scientific articles, obtained from the SciELO and PubMed bases, was carried out. The included articles were obtained since the year 2001. The article search was carried out from August 26 to October 7, 2019. The keywords used for the search were: dark chocolate, health, cardiovascular disease, polyphenols. Finally 19 articles were included.

Results

Various studies show that dark chocolate and cocoa contain a significant amount of polyphenols, mainly flavonols
,
. Its consumption leads to an increase in bioactive nitric oxide (NO) lowering blood pressure (BP)
. They also improve insulin sensitivity
,
, decrease total plasma cholesterol, in particular very low density cholesterol (LDL), modulate cell apoptosis at the endothelial level, improve cytokine balance and vascular inflammation (inhibit COX and LPO)
,
,
, inhibit platelet aggregation and endothelin‐1 synthesis (ET‐1)
,
.

Conclusion

The flavonols of dark chocolate and cocoa mainly produce a decrease in BP mediated by NO; In addition, they regulate inflammatory and metabolic processes that result in the improvement of chronic, cardiometabolic and vascular diseases. Chocolate should be considered as a recommendation in balanced nutrition.

Support or Funding Information

INSTITUTION: UPAEP

Studies on the consumption of dark chocolate and its effect on health (systematic reviews and available clinical trials)

Author

Year

Study

Sample

Metodology

Efect

Buitrago‐Lopez A, et al.

2001

Meta‐analysis

114009 in 7 cohort studies.
Age range: >18 años

Number of CV events between consumption extremes was compared.

Decreased 37% CVD (RR: 0.63; CI: 0.44–0.90) Decreased stroke 29%.

Taubert D, et al.

2003

Randomized cross clinical trial

13
BMI 21.9–26.2 with mild isolated systolic hypertension.
Age range: 55–63 years

Consumption of dark chocolate of 100 g per day (500 mg of polyphenols) for 14 days.

Participants had significantly lower systolic and diastolic pressures. The systolic mean decreased by 5.1 mmHg, and the diastolic mean decreased by 1.8 mmHg

Grassi D, et al.

2005

Clinical trial crossed

20
Age range: 18–50 years
Healthy

100 g dark chocolate (88 mg flavanols). Daily BP measurement.

BP decrease (24‐hour systolic −11.9 +/− 7.7 mmHg, P <0.0001; 24‐hour diastolic −8.5 +/− 5.0 mmHg, P <0.0001).

Taubert D, et al.

2007

Clinical trial parallel

44
Age range: >18 years
Normotensive or AHT

6.3 g of dark or white chocolate for 18 weeks. Daily BP measurement.

SBP: −2.9 (IC: −4.5, −1.3) mmHg
DBP: −1.9 (CI: −2.9, −0.9) mmHg
The prevalence of AHT decreased from 86% to 68%.

Hooper L, et al.

2008

Meta‐analysis

277 in 13 studies
Age range: >18 years
Healthy

BP changes between intervention (dark chocolate) and control.

Very heterogeneous
SBP: −5.88 (−9.55, −2.21) I2= 81%
DBP: −3.30 (−5.77, −0.83) I2= 70%

Reid K, et al.

2009

Meta‐analysis

36
Age range: 22–73 years
Prehypertensive

8 week follow up. Dark chocolate, tomato extract and placebo

No changes within or between groups

Nogueira LdeP, et al.

2012

Clinical trial parallel

20
Age range: 18–60 years
AHT + BMI: 25–34.9 kg/m2

50 g/day of dark chocolate (70%). Peripheral arterial tonometry (Endo‐PAT 200).

Increased endothelial function of 1.94 (IC: 1.76 – 2.12) to 2.22 (IC: 2.14 – 2.3)

Mogollon JA, et al.

2013

Clinical trial parallel

44
Age range: 18–37 years
Pregnant women

Dark Chocolate vs. Chocolate
“Placebo” for 12 weeks.

No differences in the change of BP or FMD

Tsang C, et al.

2019

Clinical trial

26
Age range: 23–55 years

Improve salivary cortisol levels. 25 g/day of dark chocolate with high polyphenol content (500 mg of flavonoids).

Total daily cortisol, morning cortisol and cortisol/cortisone ratio were significantly decrease (p <0.001).

CV: cardiovascular, CVD: CVD: cerebrovascular disease, RR: relative risk, BP: blood pressure, PAS: systolic blood pressure, PAD: diastolic blood pressure, AHT: arterial hypertension, BMI: body mass index, FMD: flow mediated dilation, I2: heterogeneity index.

References: Buitrajo‐Lopez A, et al. Chocolate consumption and cardiometabolic disorders; systematic review and meta analysis. BMJ. 2011; 343:d4488.

Taubert D, et al. Chocolate and blood pressure in ederly individuals with isolated systolic hipertensión. JAMA. 2003:27 (8).

Grassi D, et al. Cocoa reduces blood pressure and insulin and impoves endothelium dependent vasodilation in hypertensives. Hypertension. 2005; 46 (2).

Taubert Det al. Effects of low habitual cocoa intake on blood pressure and bioactive nitic oxide. JAMA. 2007: 4 (1).

Hooper L, et al. Flavonoids, flavonoid‐rich foods, and cardiovascular risk: a meta‐analysis of randomized controlled trials. Am J Clin Nutr. 2008; 88(1):38–50.

Ried K, et al. Dark chocolate or tomato extract for prehypertension: a randomised controlled trial. BMC Complement Altern Med. 2009; 9:22.

Nogueira Lde P, et al. Consumption of high‐polyphenol dark chocolate improves endothelial function in individuals with stage 1 hypertension and excess body weight. Int J Hypertens. 2012; 2012:147321.

Mogollon JA, et al. Blood pressure and endothelial function in healthy, pregnant women after acute and daily consumption of flavanol‐rich chocolate: a pilot, randomized controlled trial. Nutr J. 2013; 12:41.

Tsang C, et al. Effect of polyphenol‐rich dark chocolate on salivary cortisol and mood in adults. Antioxidants (Basel). 2019;29:8(6).