Recently I returned home from the grocery store with my weekly groceries, including my typical purchase of two 43 gram Hershey’s Milk Chocolate Bars with Almonds. As I munched on chocolate, consuming 210 calories and 8 gm of saturated fat, which virtually negated my morning run, I pondered the possible health benefits of chocolate, which have been reported recently.
In February, 2010 a press release from the American Academy of Neurology reported on several studies authored by Sarah Sahib (McMaster University, Hamilton, ON) demonstrating the effectiveness of chocolate in preventing and reducing the risk of stroke in prospective cohorts of patients. These studies respectively showed a reduction in first-time stroke risk in those who consumed chocolate by 22%, and a reduction in death risk for patients with previous stroke by 47% in patients who consumed 50 gm of chocolate rich in flavonoids once weekly. A third study showed no benefit. These studies will be presented at this week’s annual session of the American Academy of Neurology.
There is mounting evidence for the health benefits of chocolate, which is attributed to the high levels of flavonoids contained in cacoa. Flavonoids appear to have anti-inflammatory and anti-oxidative properties. However, the more highly processed the chocolate, the more these healthful flavonoids may be lost. In particular, roasting, fermentation and “alkalization” (Dutch processing) may contribute to the loss. Dark chocolate tends to be less processed and may contain fewer unhealthy ingredients (saturated fat and sugar) than milk chocolate. In addition, dark chocolate, compared with milk chocolate, has a higher content of cacao (>50%, compared with the 10 to 30% found in most milk chocolate).
There are three kinds of fat is chocolate: oleic acid, stearic acid and palmitic acid. Of the three, oleic acid is monounsaturated (as is olive oil) and considered healthy. Stearic and palmitic acid are saturated fats. While palmitic acid does increase LDL cholesterol (as do most saturated fats), stearic acid appears to be neutral in its cholesterol effect.
Evidence for the anti-inflammatory properties of chocolate include studies that have shown that the consumption of dark chocolate may reduce C-reactive protein (CRP) levels. (Di Giuseppe,J Nutr.2008;138:1939–1945) Clinical trials have also indicated that the consumption of dark chocolate reduces platelet dysfunction and improves endothelial function. (Flammer AJ et al. Dark Chocolate Improves Coronary Vasomotion and Reduces Platelet Reactivity. Circulation. 2007;116:2376–2382) Finally, the consumption of chocolate has been linked to a reduction in blood pressure as well as serum markers of oxidative stress (Taubert D et al. Effects of Low Habitual Cocoa Intake on Blood Pressure and Bioactive Nitric Oxide. A Randomized Controlled Trial. JAMA. 2007;298(1):49–60). This evidence all makes the findings of the prospective cohort study demonstrating a reduction in stroke risk with chocolate consumption seem more likely. However, further study with randomized controlled trials is needed to confirm these findings.
What "dose" of chocolate do I recommend for health? In most of the studies finding benefit, between 30 and 100 grams of chocolate containing 60 to 70 percent cacao were consumed weekly. My Hershey’s Milk Chocolate Bar with its lower cacao content (11%) may or may not apply. I think I’ll continue to indulge in my late afternoon snack of chocolate, but maybe I’ll try dark chocolate with a higher percent of cacao instead, and just maybe I’ll throw in a cup of coffee with it to prevent diabetes, but that’s a separate discussion.