flickr user EverJean
Chocolate comes from the seeds of the cacao tree. Like most seeds, the cacao beans are a rich source of all the nutrients needed to initiate the growth of a new plant, until it develops its roots and leaves. The astringent, bitter seeds go through a unique transformation involving fermentation, drying, shelling, roasting, and grinding before reaching its familiar form. As a result, chocolate contains at least 380 components and 10 psychoactive compounds, including several that may have potential health benefits.
The Basic Components of Food: Macronutrients
Carbohydrates: Chocolate contains a substantial amount of insoluble fiber (nearly 3 grams in a 28 g/1 oz. serving of 70% dark chocolate). Although the exact mechanism is unknown, high fiber intake has been correlated with assorted gastrointestinal health benefits and is currently an active area of research.
Proteins: Chocolate contains about 10-15% protein by weight, including the essential amino acid tryptophan.
Fats: Cocoa butter contains a mixture of saturated and unsaturated fats and makes up about 50% of the mass of the beans. Saturated fatty acids lead to a higher melting point than unsaturated fatty acids, which is why coconut butter (high in saturated stearic acid) is solid at room temperature, whereas olive oil (rich in oleic acid) is liquid at room temperature, and chocolate rapidly melts in the mouth. Much of the saturated fat in cocoa butter is in the form of stearic acid, which is rapidly converted to oleic acid by the body.
Minor components of food: Phytochemicals
Minerals: Chocolate is a rich source of many minerals. A 100 calorie serving of dark chocolate contains 31% of the recommended daily allowance (RDA) for copper, which is needed for enzyme activity, iron absorption, and glucose metabolism. The same amount of chocolate also contains 25% the RDA of iron, which is a key component of red blood cells.
Antioxidants: All life undergoes oxidative damage to the myriad chemical reactions occurring in each cell. Whenever we breathe, oxygen reacts with sugar and fats, often producing by-products known as free-radicals. These chemicals are unstable and can react withthe cell’s internal machinery, causing damage. They can interact with DNA to cause tumor growth, with the walls of blood vessels to cause a heart attack or stroke, or with the proteins in the eye to cause cataracts, macular degeneration, and blindness. A variety of chemicals can react with the free radical before they can reach other parts of the cell. These are called antioxidants, and each one is designed to repair a different type of damage.
Chocolate has one of the highest concentrations of antioxidants of any food: they can make up 12-18% the total weight of the cacao beans.
These same antioxidant molecules also have an effect on blood flow, by promoting the action of nitric oxide. The specific mechanisms are unknown, but nitric oxide appears to promote dilation of blood vessels and prevent various cardiovascular health problems.
Psychoactives: There are several chemicals naturally occurring in foods that have side effects on the human nervous system. The most common is caffeine, which is especially common in coffee beans and tea leaves. It is also contained in cacao beans, but the total amount in a serving of chocolate is a small fraction of the amount contained in a cup of coffee. Theobromine occurs at ten times the concentration of caffeine, but is a much weaker stimulant. Extremely small amounts of cannaboids and phenylethylamine are present in chocolate, but their concentration is less than, or comparable to, many other fermented foods. Experiments have shown that cravings for chocolate are due to the appearance and mouth-feel of chocolate, not the chemicals within the cacao.
A Grain of Salt
There are several reasons why it is difficult to provide definitive answers about the health effects of chocolate:
- The amounts of beneficial compounds found in chocolate greatly depend on the source of the beans and the way they are processed. These factors are usually not taken into account during clinical trials. When studying the effect of each of these chemicals in isolation, interactions among the full set of chemicals may be neglected.
- The chemicals in chocolate are likely modified during metabolism, which would alter their effect. The addition of dairy and sugar to the cacao, as well as the rest of a person’s diet, may affect the absorption of the nutrients in cacao.
- Individuals may have different biological responses to chocolate, which would alter the effect of small clinical trials. Moreover, many people have strong emotional ties to chocolate, which may have a significant impact besides the purely biochemical effects.
Summary
The cacao bean is a great source of fiber, several minerals, and a variety of antioxidants. These can be found in high-quality dark chocolate and chocolate elixirs that have at least a 70% cacao content. Milk and white chocolate, as well as most chocolate desserts, have lower concentrations of the initial cacao, so the potential health benefits would be less.
Sources
K. A. Cooper et al. Cocoa and health: a decade of research. British Journal of Nutrition 99 (2008), 1–11.
D. L. Katz, K Dought, and A. Ali. Cocoa and Chocolate in Human Health and Disease. Antioxidants & Reox Signaling. (on-line early edition)
H. McGee. On Food and Cooking. Scribner: New York (2004) 694-712.
M. Rusconi and A. Conti. Theorboma Cacao L., the Food of the Gods: A scientific approach beyond myths and claims. Pharmacological Research 61 (2010) 5-13.
I was inspired to look more into the health benefits of chocolate after enjoying the delicious recreations of historical chocolate elixirs at the Kakawa Chocolate House in Santa Fe, NM
