by R. Aiken MD PhD @rcaiken
Foods and beverages made with beans from the Theobroma cacao tree have been consumed by humans for over 5000 years, in pre-Colombian cultures along the Yucatan, including the Mayans.
Cocoa is the dried and fully fermented fatty seed of the fruit of the cocoa tree, native to the Americas. Cocoa liquor is the paste made from ground, roasted, shelled, and fermented cocoa beans, called nibs. It contains both nonfat cocoa solids and cocoa butter. Cocoa liquor is what is referred to as ‘‘percent cacao’’ on food packaging. Cocoa powder is made by removing some of the cocoa butter from the liquor.
Chocolate is a solid food made by combining cocoa liquor with cocoa butter and sugar. The proportion of cocoa liquor in the final product determines how dark the chocolate is. Milk chocolate, typically containing 10%–12% cocoa liquor, is made with the addition of condensed or powdered milk to the chocolate mixture and is the chocolate consumed most in the United States. Semisweet or bittersweet chocolate is often referred to as dark chocolate and must contain no less than 35% by weight of cocoa liquor.
Raw unprocessed cocoa is one of the richest antioxidant foods in the world. Studies indicate that cocoa has an effect on carbon dioxide levels that affect blood vessels and improve blood flow. This has positive implications, for example, on reducing the risk of stroke.
Cocoa is a rich source of polyphenols, mainly flavanols, which have been recognized for having positive effects on vascular disease, cancer, diabetes, inflammation, oxidative stress, and blood pressure. Because flavanols have the capacity to cross the blood-brain barrier, enhancing brain blood flow through the increased production of NO, which has been proposed as a mechanism involved in brain health
Any form other than raw typically contains added fat and sugar and is to be avoided.
Overall, research to date suggests that the benefits of moderate cocoa or dark chocolate consumption likely outweigh the risks of obesity and glycemic load.
 Wood, G.A.R.; Lass, R.A. (2001). Cocoa (4th ed.). Oxford: Blackwell Science.
 Shrime, M. G., Bauer, S. R., Mcdonald, A. C., Chowdhury, N. H., Coltart, C. E., & Ding, E. L. (2011). Flavonoid-Rich Cocoa Consumption Affects Multiple Cardiovascular Risk Factors in a Meta-Analysis of Short-Term Studies. Journal of Nutrition, 141(11), 1982-1988. doi:10.3945/jn.111.145482.
 Nehlig, A. (2012). The neuroprotective effects of cocoa flavanol and its influence on cognitive performance. British Journal of Clinical Pharmacology Br J Clin Pharmacol. doi:10.1111/j.1365-2125.2012.04378.x.