If you have seen metal rust or an apple turn brown, you have observed the process of oxidation. In the human body, oxidation is caused by free radical atoms and can cause conditions like cancer, heart disease and diabetes. To combat this, and age-related diseases, health experts recommend consuming antioxidants as part of your diet. Unprocessed cocoa powder, a product of the cocoa bean, contains higher levels of antioxidants than any other chocolate product, according to studies by the USDAs Agriculture Research Service.

To help consumers simplify information about the thousands of antioxidants found in foods and beverages, the USDA created an aggregate rating scale called oxygen radical absorbance capacity, or ORAC, which scores many common foods based on their free-radical-fighting power. A single cup of cocoa made from about 20 g unsweetened, unprocessed cocoa powder has an ORAC score of more than 10,000 units.

Although you can find cocoa powder on the ingredient lists of many products, scientists find that processing the powder decreases the antioxidants available. A 1.7 oz. milk chocolate bar contains a small amount of cocoa, and has a 3,500 ORAC score, while a similar-sized dark chocolate bar containing more cocoa brings in a score of 10,000. Thats an impressive rating, but for comparison, 1 Tbsp of ground cloves delivers a score of about 43,000.

As of 2011, the National Institutes of Health lists more than 300 current studies on the antioxidant effects of cocoa. The Aztecs reportedly used medicinal chocolate to treat intestinal and stomach complaints, reduce fevers and promote strength, reports "The Lancet." Scientists are researching the use of cocoa to balance HDL and LDL cholesterol levels, lower vascular inflammation and slow the growth of cancer cells.

Each of the thousands of known antioxidants combats different stressors of the human body. Since scientists don have definitive results on every combination or of every antioxidant, health experts recommend eating a wide range of ORAC-rich foods to boost your immune system and combat disease.