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Chocolate Talk with Dr. Eric Ding

March 14, 2012 Written by JP       [Font too small?]

The integration of natural medicine and rigorous science is becoming increasingly evident in the current medical landscape. Dr. Eric Ding exemplifies the philosophical shift that is presently underway. For starters, he has allopathic credentials that are beyond reproach: graduating Johns Hopkins University with Honors in Public Health and Phi Beta Kappa, then going on to become the youngest student at Harvard to complete a dual doctoral program in epidemiology and nutrition. Dr. Ding is now a faculty member at Harvard Medical School and Women’s Hospital, and is also the director and founder of the non-profit Campaign for Cancer Prevention.

The issue of fairness is a common sticking point when conventionally trained physicians approach issues that are typically the domain of alternative and complementary medicine. The advocacy of “food as medicine” and nutritional supplements for health promotion qualify as common points of contention. However, it’s important to consider each individual, regardless of their educational background, on a case-by-case basis. A few of the details that I’ve learned about Dr. Ding are helpful in defining his unique view of responsible medicine. First, he played a pivotal role in exposing the risks of Vioxx, the anti-inflammatory drug, that eventually led to its removal from the market. Also of note, Dr. Ding is a cancer survivor who has devoted his adult life to seeking out dietary and lifestyle factors that may spare others from his own experience with a life threatening tumor at the age of 17.

JP - You’ve co-authored several reviews about the relationship between chocolate consumption and cardiovascular disease. What initially spawned your interest in the health promoting effects of cocoa?

Dr. Ding - I’ve been studying cocoa for many years because of my interest in flavonoids. Notably, cocoa flavonoids are rather unique in demonstrating many CVD (cardiovascular disease) benefits.

JP - Your first systematic review of chocolate and heart disease was published at the beginning of 2006. A later meta-analysis was recently featured in the November 2011 issue of the Journal of Nutrition. What revelations have come to light in the period between the two summaries?

Dr. Ding - Between 2006 and 2011, a lot of randomized trials of cocoa flavonoids have been conducted showing benefits for CVD markers (lowering blood pressure, raising good HDL, lowering bad LDL, improving insulin sensitivity, improving endothelial function, etc), as well as several additional prospective cohort studies of cocoa and CVD mortality, which also suggests a potentially strong cardiopreventive benefit (50% decrease in one Dutch study, albeit a small study).

JP - In your youth, you survived a cancer scare and subsequently founded Campaign for Cancer Prevention. What is your view of the preliminary evidence suggesting a chemoprotective effect of chocolate consumption in animal models of cancer and in select populations such as the Kuna?

Dr. Ding - As much as I’m a cancer prevention advocate, it’s currently unclear what cancer preventive benefits cocoa may directly have so far. That said, diabetes (high glucose) has been associated with a few types of cancers, and thus, cocoa flavonoids’ benefits on improving insulin resistance may indirectly also affect long term cancer risk. But, larger long term studies would be needed for that association. That said, there are many other preventable risk factors of cancer, including not smoking, obesity, exercise, and other nutritional factors related to preventing obesity.

JP - Recent studies attest to cocoa’s ability to influence health in such disparate ways as increasing beneficial bacteria (in the gut) to reducing symptoms of chronic fatigue syndrome. Where do you see the future of cocoa research headed in the future?

Dr. Ding - I think given that cocoa research has reached a watershed moment, where the large body of short-term randomized trials and long-term observational cohort studies all suggest benefits on lowering risk of CVD … the next and final stage of gold standard scientific evidence would be long-term randomized trials for demonstrating cocoa flavonoid supplementation and risk of hard CVD endpoints (e.g. MI events and stroke events). However, such a study would require 10,000-20,000 individuals for primary prevention in healthy populations for 6-10 years, or 2000-10000 for secondary prevention / or prevention in high risk populations for 2-4 years … thus, it would likely require a consortium of organization and institutions to launch such a study, though a very necessary and important study.

JP - What do you think is the healthiest way or ways to include chocolate in one’s daily diet? Is there any scientific support for the notion that concentrated cocoa extracts are a suitable alternative to chocolate-based foods?

Dr. Ding - In our meta-analysis, interestingly, the benefits in the short-term trials were observed with doses of around 400-500 mg/day (of cocoa flavonoids), which is equivalent to 33 bars of milk chocolate or 8 bars of dark chocolate. Thus, because it is unreasonable to consume all the calories, sugar and fat to achieve these levels of cocoa flavonoids through just chocolate bars alone … supplements with concentrated cocoa flavonoids may be perhaps helpful for garnering the benefits discovered (supplements available commercially, e.g., CocoaWell supplements in 450 mg dosage). The key is getting the benefits of cocoa flavonoids for heart disease while avoiding the calories, and for that, chocolate bars are not likely the best solution.

JP - Your research background extends far beyond determining the relative merits of chocolate. Some of your recent clinical work has included a review of algae-based, omega-3 fatty acids. Can you please offer a summary of what you have discovered in the course of your evaluation?

Dr. Ding - I was a co-author on the algal oil and CVD risk factor meta-analysis. Algal oil is a non-fish source of DHA omega-3 fatty acids. We found that algal oil supplementation lowered triglycerides and raised HDL … but it also raised LDL. Thus, it had a mixed CVD profile (in contrast with cocoa, where we only found either mostly beneficial or few neutral effects). Hence, algal oil benefits for long term CVD risk is still uncertain.

JP - You also co-authored a meta-analysis on the role that physical activity plays in maintaining and promoting cardiovascular health. What was the take home message there?

Dr. Ding - That was a dose-response meta-analysis that I helped conduct to demonstrate the dose-specific effects of physical activity duration and CVD. Notably, we found that indeed, some (physical activity) is better than none, and more is better than some.

Pure Cocoa Extracts Contain High Levels of Antioxidant Phytochemicals

Source: Chemistry Central Journal 2011, 5:5  (link)

JP – Two of your studies have considered the role of resistin in the development of type-2 diabetes. Is resistin emerging as an important biomarker for diabetic risk?

Dr. Ding - No, although resistin was associated with diabetes in crude analysis, in multivariable adjusted analysis, it did not independently predict diabetes risk beyond traditional and established risk factors.

JP - Several years ago, you published a paper examining the impact of high glycemic foods in relation to cardiometabolic risk in a Chinese population. What were your conclusions and can they be extrapolated to other regions of the world?

Dr. Ding - That paper was a review highlighting the nutritional interaction (effect modification where one effect depends on another factor) between GL and obesity. Notably, while GL is less dangerous for CVD/diabetes in non-overweight populations, GL is more adverse particularly in overweight and obese populations. It’s not a China specific finding – its been found in many US and Western populations too.

JP - In 2009, you were involved in an groundbreaking analysis that looked at “preventable causes of death in the United States”. How can individuals and organizations use this information to better their lives and lower health care spending?

Dr. Ding - That US disease burden study estimates the total number of deaths in the US attributable to various risk factors (including overlapping risk factor causes). It helps highlight the greatest preventable risk factors for disease in America, which is particularly useful not just to lay public and clinicians, but also policy maker and public health priority strategies as well. Hence, it was also one of the most read articles in PLOS MEDICINE that year.

I’m a long time proponent of non-alkalized, organic cocoa. I have this variety of dark chocolate, in one form or another, almost everyday. The important research that Dr. Eric Ding has been involved with has helped shape my own opinion of the capabilities of cocoa. I’ll continue to keep a close eye for future studies that bear his name and suggest you do the same. Please click on the following embedded links if you’d like to learn more about Dr. Ding’s ongoing work at Harvard or at his Campaign for Cancer Prevention.

Note: Please check out the “Comments & Updates” section of this blog – at the bottom of the page. You can find the latest research about this topic there!

Be well!


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11 Comments & Updates to “Chocolate Talk with Dr. Eric Ding”

  1. JD Says:

    Great article and interview! Some interesting cocoa products out there these days.

  2. JP Says:

    Thank you, JD!

    Be well!


  3. Mary Brighton Says:

    Thanks for this great article!
    Love dark chocolate and push others to have a small amount in their daily diet. My personal opinion is that dark chocolate, besides its cardiovascular benefits, it can be an appetite suppressant.
    Where I live in France, chocolate is a big part of the culture. Discovered chocolate here and haven’t stopped eating! (in moderation of course).
    Bon Appetit

  4. JP Says:

    Merci, Mary.

    We had the pleasure of visiting France recently and experiencing some truly delicious and nutritious food there. It was a wonderful experience. I documented part of our travel in the following columns.



    We look forward to returning soon. :)

    Be well!


  5. JP Says:

    Update: Enjoying dark chocolate judiciously can improve the health of overweight individuals …


    Journal of Nutritional Biochemistry – February 25, 2015

    Natural cocoa consumption: Potential to reduce atherogenic factors?

    Short-term consumption of flavanol-rich cocoa has been demonstrated to improve various facets of vascular health. The purpose of the present study was to determine the effect of 4 weeks of natural cocoa consumption on selected cardiovascular disease (CVD) biomarkers in young (19–35 years) women of differing body mass indices (BMI; normal, overweight or obese). Subjects (n=24) consumed a natural cocoa-containing product (12.7 g natural cocoa, 148 kcal/serving) or an isocaloric cocoa-free placebo daily for 4 weeks in a random, double-blind manner with a 2-week washout period between treatment arms. Fasted (>8-h) blood samples were collected before and after each 4-week period. Serum was analyzed to determine lipid profile (chemistry analyzer) and CVD biomarkers (26 biomarkers). EDTA-treated blood was used to assess monocytes (CD14, CD16, v11b and CD62L), while citrate-treated blood was used to measure changes in endothelial microparticles (EMPs; CD42a−/45−/144+) by flow cytometry. Natural cocoa consumption resulted in a significant decrease in haptoglobin (P=.034), EMP concentration (P=.017) and monocyte CD62L (P=.047) in obese compared to overweight and normal-weight subjects. Natural cocoa consumption regardless of BMI group was associated with an 18% increase in high-density lipoprotein (P=.020) and a 60% decrease in EMPs (P=.047). Also, obese subjects experienced a 21% decrease in haptoglobin (P=.034) and a 24% decrease in monocyte CD62L expression in (P=.047) following 4 weeks of natural cocoa consumption. Collectively, these findings indicate that acute natural cocoa consumption was associated with decreased obesity-related disease risk. More research is needed to assess the stability of the observed short-term changes.

    Be well!


  6. JP Says:

    Updated 09/17/15:


    Br J Nutr. 2015 Sep 9:1-10.

    Cocoa flavanol intake improves endothelial function and Framingham Risk Score in healthy men and women: a randomised, controlled, double-masked trial: the Flaviola Health Study.

    Cocoa flavanol (CF) intake improves endothelial function in patients with cardiovascular risk factors and disease. We investigated the effects of CF on surrogate markers of cardiovascular health in low risk, healthy, middle-aged individuals without history, signs or symptoms of CVD. In a 1-month, open-label, one-armed pilot study, bi-daily ingestion of 450 mg of CF led to a time-dependent increase in endothelial function (measured as flow-mediated vasodilation (FMD)) that plateaued after 2 weeks. Subsequently, in a randomised, controlled, double-masked, parallel-group dietary intervention trial (Clinicaltrials.gov: NCT01799005), 100 healthy, middle-aged (35���60 years) men and women consumed either the CF-containing drink (450 mg) or a nutrient-matched CF-free control bi-daily for 1 month. The primary end point was FMD. Secondary end points included plasma lipids and blood pressure, thus enabling the calculation of Framingham Risk Scores and pulse wave velocity. At 1 month, CF increased FMD over control by 1��2 % (95 % CI 1��0, 1��4 %). CF decreased systolic and diastolic blood pressure by 4��4 mmHg (95 % CI 7��9, 0��9 mmHg) and 3��9 mmHg (95 % CI 6��7, 0��9 mmHg), pulse wave velocity by 0��4 m/s (95 % CI 0��8, 0��04 m/s), total cholesterol by 0��20 mmol/l (95 % CI 0��39, 0��01 mmol/l) and LDL-cholesterol by 0��17 mmol/l (95 % CI 0��32, 0��02 mmol/l), whereas HDL-cholesterol increased by 0��10 mmol/l (95 % CI 0��04, 0��17 mmol/l). By applying the Framingham Risk Score, CF predicted a significant lowering of 10-year risk for CHD, myocardial infarction, CVD, death from CHD and CVD. In healthy individuals, regular CF intake improved accredited cardiovascular surrogates of cardiovascular risk, demonstrating that dietary flavanols have the potential to maintain cardiovascular health even in low-risk subjects.

    Be well!


  7. JP Says:

    Updated 03/10/16:


    Heart. 2016 Mar 2.

    Chocolate consumption and risk of myocardial infarction: a prospective study and meta-analysis.

    OBJECTIVE: To examine whether chocolate consumption is associated with a reduced risk of ischaemic heart disease, we used data from a prospective study of Swedish adults and we performed a meta-analysis of available prospective data.

    METHODS AND RESULTS: The Swedish prospective study included 67 640 women and men from the Cohort of Swedish Men and the Swedish Mammography Cohort who had completed a food-frequency questionnaire and were free of cardiovascular disease at baseline. Myocardial infarction (MI) cases were ascertained through linkage with the Swedish National Patient and Cause of Death Registers. PubMed and EMBASE databases were searched from inception until 4 February 2016 to identify prospective studies on chocolate consumption and risk of ischaemic heart disease.

    RESULTS: The results from eligible studies were combined using a random-effects model. During follow-up (1998-2010), 4417 MI cases were ascertained in the Swedish study. Chocolate consumption was inversely associated with MI risk. Compared with non-consumers, the multivariable relative risk for those who consumed ≥3-4 servings/week of chocolate was 0.87 (95% CI 0.77 to 0.98; p for trend =0.04). Five prospective studies on chocolate consumption and ischaemic heart disease were identified. Together with the Swedish study, the meta-analysis included six studies with a total of 6851 ischaemic heart disease cases. The overall relative risk for the highest versus lowest category of chocolate consumption was 0.90 (95% CI 0.82 to 0.97), with little heterogeneity among studies (I2=24.3%).

    CONCLUSIONS: Chocolate consumption is associated with lower risk of MI and ischaemic heart disease.

    Be well!


  8. JP Says:

    Updated 04/19/16:


    J Hypertens. 2016 Apr 14. [Epub ahead of print]

    Flavanol-rich chocolate acutely improves arterial function and working memory performance counteracting the effects of sleep deprivation in healthy individuals.

    BACKGROUND: Sleep deprivation is a risk factor for cardiovascular disease. Cocoa flavonoids exert cardiovascular benefits and neuroprotection. Whether chocolate consumption may mitigate detrimental effects of sleep loss on cognitive performance and cardiovascular parameters has never been studied.

    AIM: We investigated the effects of flavanol-rich chocolate consumption on cognitive skills and cardiovascular parameters after sleep deprivation.

    METHODS: Thirty-two healthy participants underwent two baseline sessions after one night of undisturbed sleep and two experimental sessions after one night of total sleep deprivation. Two hours before each testing session, participants were randomly assigned to consume high or poor flavanol chocolate bars. During the tests were evaluated, the Psychomotor Vigilance Task and a working memory task, office SBP and DBP, flow-mediated dilation and pulse-wave velocity.

    RESULTS: Sleep deprivation increased SBP/DBP. SBP/DBP and pulse pressure were lower after flavanol-rich treatment respect to flavanol-poor treatment (SBP: 116.9 ± 1.6 vs. 120.8 ± 1.9 mmHg, respectively, P = 0.00005; DBP: 70.5 ± 1.2 vs. 72.3 ± 1.2 mmHg, respectively, P = 0.01; pulse pressure: 46.4 ± 1.3 vs. 48.4 ± 1.5 mmHg, P = 0.004). Sleep deprivation impaired flow-mediated dilation (5.5 ± 0.5 vs. 6.5 ± 0.6%, P = 0.02), flavanol-rich, but not flavanol-poor chocolate counteracted this alteration (flavanol-rich/flavanol-poor chocolate: 7.0 ± 0.6 vs. 5.0 ± 0.4%, P = 0.000001). Flavanol-rich chocolate mitigated the pulse-wave velocity increase (P = 0.001). Flavanol-rich chocolate preserved working memory accuracy in women after sleep deprivation. Flow-mediated dilation correlated with working memory performance accuracy in the sleep condition (P = 0.04).

    CONCLUSION: Flavanol-rich chocolate counteracted vascular impairment after sleep deprivation and restored working memory performance. Improvement in cognitive performance could be because of the effects of cocoa flavonoids on blood pressure and peripheral and central blood flow.

    Be well!


  9. JP Says:

    Updated 08/08/16:


    Food Funct. 2016 Aug 5.

    Beneficial effects of dark chocolate on exercise capacity in sedentary subjects: underlying mechanisms. A double blind, randomized, placebo controlled trial.

    In heart failure patients the consumption of (-)-epicatechin ((-)-Epi)-rich cocoa can restore skeletal muscle (SkM) mitochondrial structure and decrease biomarkers of oxidative stress. However, nothing is known about its effects on exercise capacity and underlying mechanisms in normal, sedentary subjects. Twenty normal, sedentary subjects (∼50 years old) were randomized to placebo or dark chocolate (DC) groups and consumed 20 g of the products for 3 months. Subjects underwent before and after treatment, bicycle ergometry to assess VO2 max and work, SkM biopsy to assess changes in mitochondrial density, function and oxidative stress and blood sampling to assess metabolic endpoints. Seventeen subjects completed the trial. In the DC group (n = 9), VO2 max increased (17% increase, p = 0.056) as well as maximum work (watts) achieved (p = 0.026) with no changes with placebo (n = 8). The DC group evidenced increases in HDL levels (p = 0.005) and decreased triglycerides (p = 0.07). With DC, SkM evidenced significant increases in protein levels for LKB1, AMPK and PGC1α and in their active forms (phosphorylated AMPK and LKB1) as well as in citrate synthase activity while no changes were observed in mitochondrial density. With DC, significant increases in SkM reduced glutathione levels and decreases in protein carbonylation were observed. Improvements in maximum work achieved and VO2 max may be due to DC activation of upstream control systems and enhancement of SkM mitochondria efficiency. Larger clinical studies are warranted to confirm these observations.

    Be well!


  10. JP Says:

    Updated 10/24/16:


    Appetite. 2016 Oct 8;108:263-269.

    Habitual chocolate intake and type 2 diabetes mellitus in the Maine-Syracuse Longitudinal Study: (1975-2010): Prospective observations.

    Compounds in cocoa and chocolate have established cardiovascular benefits, including beneficial effects on insulin resistance, a risk factor for type 2 diabetes mellitus. The aims of this study was to investigate relations between habitual chocolate intakes and diabetes mellitus. Cross-sectional and prospective analyses were undertaken on 953 community-dwelling participants (mean age 62 years, 59% women) from the Maine-Syracuse Longitudinal Study (MSLS). Habitual chocolate intakes, measured using a food frequency questionnaire, were related to prevalence of diabetes mellitus (cross-sectionally) and with risk of diabetes measured approximately five years later (prospectively). We also examined the relation between diabetes (the predictor) and chocolate consumption (the outcome) up to 30 years later. Chocolate intake was inversely associated with type 2 diabetes. Compared to participants who consumed chocolate more than once per week, those who never or rarely ate chocolate exhibited a significantly higher odds of having type 2 diabetes 5 years later (OR: 1.91, 95% CI: 1.03, 3.55, p = 0.04), after adjustment for cardiovascular, lifestyle and dietary factors including other polyphenol-rich beverages. However, individuals diagnosed with diabetes prior to the nutritional assessment consumed lower amounts of chocolate at the time of the dietary assessment. Our findings suggest that relations between chocolate and type 2 diabetes may be bi-directional.

    Be well!


  11. JP Says:

    Updated 07/08/17:


    Nutrients. 2017 Jul 2;9(7).

    Chocolate Consumption and Risk of Coronary Heart Disease, Stroke, and Diabetes: A Meta-Analysis of Prospective Studies.

    Although epidemiological studies have examined the role of chocolate in preventing cardiometabolic disease, the results remain inconsistent. Herein, we conducted a meta-analysis of prospective studies to determine the association between chocolate intake and risk of coronary heart disease (CHD), stroke, and diabetes. A systematical search in PubMed and Embase through March 2017, together with reference scrutiny of relevant literatures, was performed to identify eligible studies. Relative risks (RRs) and 95% confidence intervals (CIs) were pooled using random effect models. Fourteen prospective studies of primary prevention with 508,705 participants were finally included, with follow-up durations ranging from 5 to 16 years. The summary RRs for the highest versus lowest chocolate consumption were 0.90 (95% CI: 0.82-0.97; n = 6) for CHD, 0.84 (95% CI: 0.78-0.90; n = 7) for stroke, and 0.82 (95% CI: 0.70-0.96; n = 5) for diabetes. Dose-response meta-analysis suggested a nonlinear association of chocolate consumption with all outcomes. For both CHD and stroke, there was little additional risk reduction when consuming chocolate ≥3 servings/week (one serving was defined as 30 g of chocolate). For diabetes, the peak protective effect of chocolate emerged at 2 servings/week (RR: 0.75, 95% CI: 0.63-0.89), with no benefit observed when increasing consumption above 6 servings/week. In conclusion, chocolate intake is associated with decreased risks of CHD, stroke, and diabetes. Consuming chocolate in moderation (≤6 servings/week) may be optimal for preventing these disorders.

    Be well!


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