Far from being an unhealthy indulgence, dark chocolate actually has a number of potential health benefits when consumed in moderation. Dark chocolate contains flavonoids -- compounds that act as antioxidants. The flavonoids in dark chocolate, called flavanols, act as antioxidants. Antioxidants reduce free radicals -- molecules that cause cell damage. Flavanols may also have other vascular health benefits. Since most dark chocolate does contain sugar and fat, consume it in moderation to avoid weight gain.
Blood Pressure
Dark chocolate can help reduce blood pressure slightly and improve endothelial function, a Yale Prevention Research Center study reported in the July 2008 "American Journal of Clinical Nutrition." Endothelial cells, which line the arteries, produce nitric acid, a chemical that relaxes and dilates blood vessels to manage blood pressure. The study, reported by lead author Zubaida Faridi, M.D., assistant director of the center, found that dark chocolate in bar form and both sugar-free and regular cocoa powder reduced blood pressure in overweight but otherwise healthy adults. Endothelial function improved more when sugar-free cocoa was taken. This benefit decreases once the daily dose of dark chocolate stops, Harvard Health Publications reports. A 2005 study conducted by the University of L'Aquila and reported in the same journal by lead author Davide Grassi, M.D. found that dark chocolate reduced blood pressure but white chocolate did not.
Cholesterol
As an antioxidant, dark chocolate can improve cholesterol levels by decreasing oxidation of low-density lipoprotein, the so-called "bad" type of cholesterol and raising high-density lipoprotein, the "good" cholesterol. A study in the March 2007 "American Journal of Clinical Nutrition," by Seigo Baba of the Food and Health R&D Laboratories in Japan, compared lipid levels after 12 weeks of cocoa or placebo. The cocoa group had a 24 increase in HDL levels and a decrease in LDL oxidation.
Insulin Sensitivity
The 2005 study conducted by Dr. Grassi also found that dark chocolate but not white chocolate decreased insulin sensitivity. Insulin sensitivity contributes to development of metabolic resistance, which can lead to type 2 diabetes.
Platelet Aggregation
Platelets are necessary clotting factors in blood. But platelets sticking together to form clots at the site of atherosclerotic plaques in blood vessels can increase the risk of clot formation, which narrows arteries and can increase the risk of heart attack. Clots can break off, traveling to the brain and lodging in blood vessel to cause stroke. A study reported in the August 2003 issue of "Platelets" found that dark chocolate inhibited platelet aggregation. Milk chocolate and white chocolate did not have this effect, lead author Andrew Innes, M.D of Ninewells Hospital and Medical School reported.
References
- Harvard Health Publications: The Health Benefits of That Heart-Shaped Box of Dark Chocolate
- Women to Women: An Introduction to Insulin Resistance
- PubMed: Short-Term Administration of Dark Chocolate is Followed By a Significant Increase in Insulin Sensitivity and a Decrease in Blood Pressure in Healthy Persons
- PubMed.gov; Acute Dark Chocolate and Cocoa Ingestion and Endothelial Function: a Randomized Controlled Crossover Trial
- Harvard Medical School Family Heakth Guide: Aspirin for Heart Attack: Chew or Swallow?
- PubMed.gov: Continuous intake of polyphenolic compounds containing cocoa powder reduces LDL oxidative susceptibility and has beneficial effects on plasma HDL-Cholesterol Concentrations in Humans.
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