Category Archives: Chocolate

Health Benefits of Dark Chocolate

Posted on June 4, 2012 | Comments Off

Theobroma cacao, the cocoa tree, has been cultivated in Central and South America for over 3000 years. Cocoa is derived from the tree’s seed, also known as the cocoa bean.

Chocolate is a product of the processed cocoa bean. Sweet chocolate is chocolate combined with sugar. Milk chocolate is sweet chocolate combined with milk powder or condensed milk. Dark chocolate typically has no added dairy products, has at least 65% cocoa content, and has much more of the potentially healthy chemicals from the cocoa bean as compared with milk chocolate. White chocolate is cocoa butter (aka cacao fat), milk solids, and sugar without the cocoa solids or mass; in many countries it is not considered chocolate.

It’s been a little over 10 years since we first read in a medical journal about cocoa and chocolate as potential sources of antioxidants for health. What have we learned since then?

Phytochemicals are chemicals produced by plants, and there are hundreds of thousands of them. Polyphenols are a subset of phytochemicals. Flavonoids, with strong antioxidant properties, are a subset of polyphenols. And a subset of flavonoids, called flavonols, have particularly potent biological effects in humans. Prominent flavonols in dark chocolate are flavan-3-ol, catechin, and epicatechin. Also metabolically active are proanthocyanidins, which are polymeric condensation products of flavan-3-ol.

Are you bored yet? Have I convinced you of my authority on the subject? Say yes, or I’ll keep going! [Please say yes: I’m boring myself!]

Note that some chocolate manufacturers process the cocoa beans to remove some of the polyphenols, which reduces bitterness or pungency.

Other rich sources of flavonols are wine, tea, and various fruits and berries.

How could dark chocolate, especially its flavonoids, be healthful?

Flavonoids are antioxidants that protect from injury caused by free radicals
Enhanced nitric oxide production, leading to relaxation of arteries (vasodilation), leading to reduced blood pressure: up to 6 mmHg systolic and 3 mmHg diastolic
Elevation of HDL cholesterol, with no effect on total and LDL cholesterol
Inhibition of platelet aggregation and activation, leading to fewer blood clots that cause heart attacks and strokes
Decreased inflammation
Reduction of C-reactive protein, a marker of inflammation
Decreased neutrophil (white blood cell) activation. White blood cells play a role in inflammation
Decreased LDL cholesterol oxidation, leading to fewer atherosclerotic complications
Improved function of the cells that line blood vessels (endothelium)
Possible enhanced insulin sensitivity
May act as anti-carcinogens and neuro-protective agents
May act as an antidepressant

Note also that low-fat natural non-alkalized cocoa powder is also a rich source of antioxidant flavonoids.

Bottom line? Dark chocolate, especially because of flavonoids, may well be protective against cardiovascular disease such as heart attacks and strokes.

[Did you notice I’m waffling . . . may be protective.]

What’s in dark chocolate other than flavonoids?

A 40 gram serving of a fine dark chocolate bar has:

Calories: 200
Calories from fat: 150
Fiber: 4.5 grams (dark chocolate is a good source of fiber on a “per calorie” basis)
Sugar: 11 grams
Saturated fats: 10 grams

But aren’t saturated fats bad for me?

The fats in dark chocolate are 1/3 oleic (healthy monounsaturated, as in olive oil), 1/3 stearic (saturated, but no effect on cholesterol levels, unlike some other saturated fats), and 1/3 palmitic (saturated, and could increase cholesterol levels and heart risk). So it’s sort of a wash.

[I’m not getting into the diet-heart hypothesis now. Don’t bait me.]

What’s the healthy “dose” of dark chocolate?

No one is sure. It’s certainly no more than 100 grams (3.5 ounces) a day, and the optimal dose may be as low as 20 grams every three days. If you eat too much, it will make you fat. 100 grams is 500 calories; that’s probably way too much. Even if you start eating 20 grams – 100 calories – every three days, you will gain weight unless you give up some other food or exercise a little more.

Parker, why are you waffling?

Because no one has ever done a study to see if adding dark chocolate actually reduces death rates or sickness from specific diseases in humans. I think it probably does, but who knows for sure? Nobody. What we need is a randomized, controlled trial of dark chocolate as a supplement in 10,000 middle-aged adults followed over the course of 10 years. I’d sign up for that in a heartbeat. Just don’t give me the placebo.

Steve Parker, M.D.

Additional Resources:

Clay Gordon, author of the book Discover Chocolate, kindly critiqued an early version of this blog post here. If the link doesn’t work, go to The Chocolate Life and search “Health Benefits of Chocolate” in the Forums.

References:

Erdman, J.W., et al. Effects of cocoa flavanols on risk factors for cardiovascular disease. Asian Pacific Journal of Clinical Nutrition, 17 supplement 1 (2008): 284-287.

Farouque, H.M, et al. Acute and chronic effects of flavanol-rich cocoa on vascular function in subjects with coronary artery disease: a randomized double-blind placebo-controlled study. Clinical Science, 111 (2006): 71-80.

Heptinstall, S., et al. Cocoa flavanols and platelet and leukocyte function: recent in vitro and ex vivo studies in healthy adults. Journal of Cardiovascular Pharmacology, 47 supplement 2 (2006): S197-205.

Keen, C.L., et al. Cocoa antioxidants and cardiovascular health. American Journal of Clinical Nutrition, 81 supplement 1 (2005): 298S-303S.

Mehrinfar, R. and Frishman, W.H. Flavanol-rich cocoa: a cardioprotective nutraceutical. Cardiology Reviews, 16 (2008): 109-115.

Engler, M.B, and Engler, M.M. The emerging role of flavonoid-rich cocoa and chocolate in cardiovascular health and disease. Nutrition Reviews, 64 (2006): 109-118.

Lippi, G. et al. Dark chocolate: consumption for pleasure or therapy? Journal of Thrombosis and Thrombolysis, September 23, 2008 (Epub ahead of print).

Hooper, L, et al. Flavonoids, flavonoid-rich foods, and cardiovascular risk: a meta-analysis of randomized controlled trials. American Journal of Clinical Nutrition, 88 (2008): 38-50.

Cooper, K.A., et al. Cocoa and health: a decade of research. British Journal of Nutrition, 99 (2007): 1-11. Epub August 1, 2007.

Aron, P.M., and Kennedy, J.A. Flavon-3-ols: nature, occurrence and biological activity. Molecular Nutrition and Food Research, 52 (2008): 79-104.

Buijsse, B, et al. Cocoa intake, blood pressure, and cardiovascular mortality [in men]: the Zutphen Elderly Study. Archives of Internal Medicine, 166 (2006): 411-417.

Ding, E.L., et al. Chocolate and prevention of cardiovascular disease: a systematic review. Nutrition and Metabolism, 3 (2006): 2.

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Posted in Chocolate

Tagged cardiovascular disease, chocolate, dark chocolate, heart disease

If Dark Chocolate Is Healthy, What’s The Right Dose?

Posted on June 3, 2012 | Comments Off

Antioxidant flavonoids and other phytonutrients in dark chocolate are thought possibly to improve health, primarily through reduction in cardiovascular diseases such as heart attacks and strokes. I previously blogged about these and other potential health benefits of dark chocolate.

In terms of a medicinal agent, we have not been sure of the therapeutic “dose.” A recent study out of Italy provides a clue.

Researchers at Catholic University, Campobasso, Italy, surveyed residents in southern Italy regarding chocolate intake and measured their C-reactive protein (CRP) levels. CRP is a marker of inflammation and a predictor of coronary artery disease such as heart attacks. Generally, higher levels of CRP are associated with higher risk of heart attacks. If you have a choice, go for lower levels of CRP.

Methodology

Participants in the study were selected by simple random sampling from city hall registries and were at least 35 years old. Researchers were looking for healthy people, so the following were excluded from the study: those who reported known cardiovascular disease, eating a special diet, or on drug therapy for high blood pressure, diabetes, or adverse blood lipids. Twenty percent of initial recruits refused to participate. Of the 10,994 initial recruits, 4,849 men and women made it into the final study.

Of the 4,849 subjects, two subgroups were identified: 1) a control group of 1,317 (27%) who never ate any type of chocolate, and 2) a test group of 824 (17%) subjects who regularly ate dark chocolate only.

Interviewers administered questionnaires to the subjects to document clinical and personal information such as dietary habits, socioeconomic status, physical activity, medical history, risk factors for cardiovascular disaese and tumors, family history of cardiovascular disease, drug use, etc.

Regarding chocolate consumption, participants were asked about frequency – daily, weekly, or monthly – of a “standard dose” (20 grams) and about type of chocolate: milk, dark, nut chocolate, or any type. Someone eating more than one type of chocolate was classified as “any type.”

Other measurements: blood pressure, weight, height, waist circumference, blood glucose, serum lipids (various cholesterols and triglycerides), and high-sensitivity C-reactive protein.

Findings

Age-adjusted CRP levels were lower in dark chocolate users (1.13 mg/L) than in the nonconsumers of chocolate (1.30 mg/L).

Dark chocolate eaters were divided into thirds: the lowest third of average consumption, the middle third, and the highest third. The lowest third ate under 19 grams per week. The middle third ate between 19 and 47 grams per week. The highest third ate over47 grams per week. The chocolate-related reduction in CRP was lost in people who were in the highest third (or tertile), i.e., eating more than 47 grams a week or 20 grams every three days. People in the lowest tertile of dark chocolate consumption had a CRP reduction the same as the middle third.

Systolic blood pressure in dark chocolate consumers was 3 mmHg lower than the pressure in nonconsumers. No difference in diastolic pressures.

Discussion

The researchers cite two clinical trials that investigated the effect of cocoa on markers of inflammation but did not find any association. They wonder if those studies enrolled too few participants, or whether the relatively high doses of chocolate masked the effect. In the present study, the lowering of CRP was seen in consumption of up to 20 grams every three days, but seemed to disappear at higher doses.

The authors write that:

. . . regular intake of small amounts of dark chocolate . . . consumption should have no harmful effect on anthropometric variables such as BMI [body mass index] and waist:hip ratio and can be viewed as a promising behavioural approach to lower, in a quite pleasant way, cardiovascular risk factors at a general population level.

According to data reported in apparently healthy American men and women, ranges of serum CRP measured in our nonchocolate consumer population would belong to a “moderate” risk estimate quintile, whereas the ranges found in dark chocolate consumers would be classified as a “mild” risk estimate. For the decrease in serum CRP values from moderate to mild quintile, the relative risk of suffering a future cardiovascular event would apparently decrease by 26% in men and 33% in women.

The authors are careful to point out that this study does not prove that low-dose dark chocolate lowers CRP levels. It’s an association. “Additional studies are necessary to explain the mechanisms linking dark chocolate consumption and regulation of serum CRP concentrations.”

My Comments

The healthy dose of dark chocolate may be quite small: no more than 20 grams every three days, and perhaps quite a bit less. This is not much by U.S. standards. The serving size listed on many bars here is 40 grams. Forty grams has about 200 calories. Twenty grams twice a week translates to 29 calories a day.

The authors of this study don’t address whether 40 grams a week would be just as healthy as 80 grams every two weeks.

Eating more, on average, than 20 grams every three days may entirely wipe out the healthy effects. This effect is like wine’s: a little is probably good for you, too much is either neutral or harmful.

I’m sorry to be so wishy-washy on this issue, but that’s the state of the science today. The study at hand may help us optimize dark chocolate’s effect on C-reactive protein. But dark chocolate’s other healthy effects may require other doses, higher or lower.

The next step is to take 20,000 middle-aged people, give half of them various doses of scheduled dark chocolate, give the other half placebos, then record rates of diseases and death over the next 10 years. Who would pay for this multi-million dollar study? Either government or chocolate manufacturers.