Various studies over the years have suggested that naturally occurring compounds in chocolate called flavanols can confer some health benefits, such as lowering blood pressure. Two reports of research emerging in 2014 may help to explain why. See also: Cacao; Cocoa powder and chocolate; Disease; Nutrition

Flavanols in cocoa consist of molecules called catechins and procyanidins, which are chains of two or more catechin monomers linked together. Procyanidins made of two or three catechins (dicatechins and tricatechins, respectively) are said to be oligomeric. Procyanidins with more than three catechin subunits are called polymeric. See also: Flavonoid; Molecular isomerism

Catechin has two chiral centers and, as a result, has four diastereoisomers: two cis isomers and two trans isomers. The trans isomers are called catechin and the cis isomers are called epicatechin. Shown are one isomer of catechin and one isomer of epicatechin.

In February 2014, researchers from Virginia Polytechnic Institute reported in the Journal of Agricultural and Food Chemistry results for mice fed a high-fat diet supplemented with one of four different types of cocoa flavanol: monomers, oligomers, polymers, or a mixture (cocoa flavanol extract). The oligomers seemed to be the most effective or active with respect to health: the mice that received the supplement containing mostly oligomeric procyanidins showed the least weight gain and insulin resistance. Both insulin resistance and obesity are risk factors for developing type-2 diabetes. See also: Diabetes; Insulin; Obesity; Polymerization; Type 2 diabetes

At the American Chemical Society National Meeting and Exposition in March 2014, researchers from Louisiana State University reported preliminary findings from experiments simulating the digestion of cocoa powders in the gut. Their work indicated that flavanols were broken down by bacteria to simpler chemical compounds, known as phenolic acids, which may have anti-inflammatory properties. These phenolic acids could, in theory, relax blood vessels to help prevent heart disease. Although further research will be needed to confirm the results, this report does offer one possible explanation for chocolate’s blood-pressure-lowering properties. See also: Digestive system; Heart disorders; Hypertension; Phytochemicals