The Effect of Chocolate Consumption on Cardiovascular Disease Risk Factors

Stephanie BeckerNovember 24, 2014

Outline• Purpose

• Background

• Methods

• Findings

• Conclusions

• Implications

• Future Research Required

Purpose

• To examine the relationship between chocolate consumption and cardiovascular disease risk.

Cardiovascular Disease (CVD)

• Leading cause of death for Americans equating to 34% of all deaths.

• 60,000 Americans die from CVD every year.

• Every 1 in 4 deaths is CVD related.

(Center for Disease Control, 2014)

Cardiovascular Disease Risk Factors

• Hypertension• High LDL-C• Low HDL-C• Oxidative Stress• High BMI• Lack of Physical Activity• Poor Diet

How Can Chocolate Help?

• Polyphenols:– A phytochemical found in chocolate thought to be

responsible for combating CVD risk factors.

– Found in teas and fruit juices as well. Chocolate has been found to have one of the highest polyphenol contents compared to other foods.

Methods

• Simmons College Library Network– Medline, CINAHAL, Web of Science, Academic Search Complete

• Keywords– Chocolate OR Cocoa OR Cacao– AND Cardiovascular disease OR Cardiovascular risk factors

• Techniques– Thesaurus, Boolean operators, Citation Index

Methods

• Inclusion Criteria:– Published in 2010 or later– Peer Reviewed Academic Journal

• Exclusion Criteria:– Language other than English– Literature reviews– Animal subjects

• A total of 15 studies were used for this literature review.

ResultsTopic # of Studies Design Association

(Yes)Association

(No)CVD Risk and CVD Mortality

2 (1) Prospective Cohort(1) Cross-Sectional

2 0

Blood Pressure 5 (4) Randomized Controlled Trials(1) Longitudinal

5 0

Serum Cholesterol

3 (3) Randomized Controlled Trials

3 0

Other CVD Risk Factors

8 (6) Randomized Controlled Trials(1) Cross-sectional(1) Intervention Clinical Trial

7 1

Chocolate Consumption, CVD Risk, and CVD Mortality

Topic # of Studies Design Association (Yes)

Association (No)

Chocolate Consumption, CVD Risk, and CVD Mortality

2 (1)Prospective Cohort(1) Cross-Sectional

2 0

• Both studies used food frequency questionnaires to access chocolate intake.

• The prospective cohort study had a 7 year follow up when the National Death Index was used in order to access mortality.

• Both studies recruited subjects from previous cohort studies

Chocolate Consumption, CVD Risk, and CVD Mortality

Author/Date Design/# of Subjects Results

Djousse et al., 2011 Cross- sectional/ 4,970 Those who consumed chocolate had a lower risk of CVD (P trend <0.0001)

McCullough et al., 2012 Prospective Cohort/98,469 Those in the top quartile of flavonoid intake compared to the bottom quartile had a lower risk of fatal CVD (p trend= 0.01)

Strengths and Limitations

• Strengths:– Large sample sizes– Accurate dietary software– Drop off rate for prospective cohort was only 11%

• Limitations:– Self-Reporting– Diets not controlled during the follow up period

Chocolate Consumption and Blood Pressure

Topic # of Studies Design Association (Yes)

Association (No)

Chocolate Consumption

and Blood Pressure

5 (4) Randomized Controlled Trials(1) Longitudinal

5 0

• All clinical trials provided their own chocolate products

• The longitudinal study was based on a food frequency questionnaire.

Chocolate Consumption and Blood Pressure

Author/Date Design/# of subjects Results

Almoosawi et al., 2010 Randomized cross-over/14 SBP and DBP both significantly lower then baseline (SBP: p=0.001,

DBP: p=0.001)Almoosawi et al., 2012 Randomized cross-over/42 SBP reduced in normal

weight and overweight group (NW: p=0.014, OW: P=0.016) DBP reduction in

overweight group (p<0.001)

Bogaard et al., 2010 Randomized 3-period cross-over/

High dose theobromine showed a reduction in both SBP and DBP compared to placebo (SBP: P<0.01, DBP:

p=0.04)

Chocolate Consumption and Blood Pressure

Author/Date Design/# of Subjects Results

Sudarma et al., 2011 Parallel Randomized Clinical Trial/32

Significant difference in SBP in treatment vs.

control (p=0.001). No significant difference in

DBP (p=0.308)Buijsse et al., 2010 Longitudinal/19,357 Significant difference in

SBP and DBP in the top quartile for chocolate consumption vs. the

bottom quartile (SBP: p<0.00001, DBP: p=0.014)

Strengths and Limitations

• Strengths:– Majority of trials used a standard cocoa product– Strict inclusion criteria– Longitudinal study had a large sample size

• Limitations:– Clinical trials had small sample sizes– All studies were done on people with different

CVD risk factors

Chocolate Consumption and Serum Cholesterol Levels

Topic #of studies Design Association (Yes)

Association (No)

Chocolate Consumption

and Serum Cholesterol

Levels

3 (3) Randomized Controlled Trials

3 0

• All studies provided chocolate products to participants

Chocolate Consumption and Serum Cholesterol Levels

Author/Date Design/# of Subjects Results

Anuzzi, et al., 2010 2x2 factorial/86 A significant reduction was shown in VLDL-C in

treatment vs. control (p=0.016)

Khan et al., 2011 Randomized cross-over/47 A significant reduction in LDL-C (p=0.001 and a

significant increase in HDL-C (p=0.008) was found in

treatment vs. control.Sola et al., 2012 Parallel multi-centered/113 Reduction in LDL-C and

Apo B/Apo A ratio in treatment vs. control (p=0.002, p=0.0085)

Strengths and Limitations

• Strengths:– Diets were kept uniform in all studies (Sola et al.,

kept participants on a low saturated fat diet)– Large sample size compared to other clinical trials

• Limitations:– Short trial periods– Compliance to these specific diets is unknown

Chocolate Consumption and Other CVD Risk Factors

Topic # of Studies Design Association (Yes)

Association (No)

Chocolate Consumption

and Other CVD Risk Factors

8 (6) Randomized Controlled Trials(1) Intervention Trial(1) Cross-sectional

7 1

• Various CVD Risk factors were tested including: Nitric Oxide levels, fasting glucose levels, DNA methylation, arterial stiffness, and endothelial function.

• 3 studies in this section were also used in other sections

Chocolate Consumption and Other CVD Risk Factors

Author/Date Design/# of Subjects Results

Crescenti et al., 2013 Randomized Controlled Trial/254

Peripheral leukocyte DNA methylation status was

significantly lower in the treatment group vs. control

(p< 0.001)Flammer et al., 2011 Randomized Controlled

Trial/22No significant results

found.West et al., 2013 Randomized cross-over/ 30 Hyperaemic blood flow

increased post treatment (Basal: p=0.04, peak:

p=0.03). Augmentation Index at 75bpm was

decreased in women post treatment (p=0.01)

Chocolate Consumption and Other CVD Risk Factors

Author/Date Design/# of Subjects Results

Nogeuria et al., 2012 Intervention Trial/20 Significant increase in endothelial function after

intervention (p=0.01)Djousse et al., 2011 Cross-Sectional/2,217 Increased chocolate

consumption decreased calcified atherosclerotic

plaque in coronary arteries (p trend= 0.022)

Sudarma et al., 2011* Parallel Randomized Clinical Trial/32

Nitric Oxide Serum levels significantly higher in

treatment vs. control group (p=0.001)

* Represents a study that was also used in a previous section

Chocolate Consumption and Other CVD Risk Factors

Author/Date Design/# of Subjects Results

Almoosawi et al., 2010* Randomized cross-over/14 Significant reduction on fasting glucose levels in

treatment vs. control group (p=0.026)

Almoosawi et al., 2012* Randomized cross-over/42 Fasting glucose and HOMA-IR were reduced from

baseline in participants with a BMI ≥ 25 kg/m2 (FG:

p<0.001, HOMA-IR: p=0.041)

Strengths and Limitations

• Strengths:– Multiple risk factored studied to get a broader

view on the effect that chocolate has on CVD risk.– Different study designs used.

• Limitations:– Very few studies were done on each individual risk

factor, therefore it is difficult to draw significant conclusions.

Conclusions

• All studies, with the exception of the study conducted by Flammer et al. showed an association between chocolate consumption and CVD risk.

• Chocolate consumption reduced systolic blood pressure more significantly then diastolic blood pressure.

• Polyphenols in chocolate were shown to reduce various CVD risk factors.

Implications

• Regular consumption of dark chocolate may help to lower CVD risk factors in those individuals who already have a higher then average CVD risk.

• In order to prevent other CVD risk factors it is recommended to add chocolate to a low saturated fat diet.

Future Research

• Research needs to be done on healthy subjects without any CVD risks.

• The exact mechanism of how chocolate lowers CVD risk is unknown. Further research needs to be done on the biological level to find the exact mechanism.

• There is now a chocolate shortage, how to counteract that?

Thank you for your time!

Questions?