In further studies conducted by Dr. Norman K. Hollenberg, professor of medicine at Brigham and Women's Hospital and Harvard Medical School found that flavonols may also help vessels dilate and help keep platelets from clustering on the blood vessel walls. Flavonoids found in hot chocolate are beneficial to health mainly because they shield the walls of blood vessels from free radical damage. Flavanols are also thought to help reduce blood platelet buildup and can balance levels of compounds called eicosanoids, which may be beneficial to cardiovascular health.