Chocolate > Health & Nutrition > Health > Emerging Areas Emerging Areas of Research
Skin Health
It is a common myth and belief that the consumption of chocolate causes acne, however, studies of chocolate and acne date back to the 1960s with none finding a relationship between chocolate consumption and acne (1). In one study, subjects consumed a chocolate bar and placebo bar that were similar in fat and sugar content (1). Although this was a short-term study, researchers found no effect of chocolate on acne or sebum (the oily substance secreted by glands) production (1).
Preliminary research indicates that chocolate with high flavanol content may protect the skin against the harmful effects of UV rays (2). In a 2009 double-blind study, subjects were either given chocolate that was high (>600 mg/20 g portion) or low (<30 mg/20 g portion) in flavanol content. Subjects underwent increasing UV doses and skin was assessed. The study found regular consumption of 20 grams of high flavanol chocolate protected skin from harmful UV effects whereas low flavanol chocolate was not found to have photoprotective effects (2). Another study also found high flavanol cocoa to have beneficial skin effects. When individuals consumed high flavanol (329 mg total flavanols) cocoa daily for twelve weeks, there was decreased reddening of the skin following UV exposure (3). High flavanol cocoa also resulted in an increase in blood flow to cutaneous and subcutaneous tissues of the skin as well as decreased skin roughness and scaling. Although more studies are needed, these studies suggest that cocoa and chocolate high in flavanols may decrease the skin’s sensitivity to UV light, and therefore may help reduce the damage caused by UV exposure and potentially skin aging.
Weight Management
Limited research has been done examining the role of chocolate in weight loss and weight management diets. Although the role of chocolate has not been specifically studied, weight management has been observed in several studies in which chocolate was part of the diet. One blood pressure study found that consumption of 100 g of dark chocolate containing 500 mg of polyphenols for 14 days had no effect on BMI, lipids, or glucose levels in the body (10). Another study examining vascular function as a result of consuming flavanol-containing cocoa also found no change in BMI in the treatment group (11). Yet another study found individuals who consume chocolate daily (> 1 time/day) have a significantly lower body weight and BMI than those who rarely consume chocolate (<1 time/week) (12). Future research is needed to examine the purposeful inclusion of chocolate and cocoa in the diet and its specific effects on weight management.
Oral Health
Dental health is dependent upon multiple factors including oral hygiene, fluoride intake, genetics, and the diet. Within the diet, foods that contain high amounts of fermentable carbohydrates are more likely to cause dental caries. However, caries formation is also dependent upon the amount of time these fermentable carbohydrates spend in the mouth. Fermentable carbohydrates are sugars and starches that stick to teeth and are easily broken down by bacteria. Although chocolate contains fermentable carbohydrates, these do not stay in the mouth long enough to play a role in the development of dental caries. In a study examining the food intake of children, no association was found between chocolate consumption and dental caries (4). It is thought the flavanols in chocolate and cocoa may decrease plaque accumulation and therefore contribute to oral health (5). More research is needed to determine the mechanism of potential caries prevention through cocoa and chocolate.
Insulin Sensitivity
Recent research has also focused on the relationship between cocoa and dark chocolate consumption and insulin sensitivity. Epicatechin, one of the main flavanols in cocoa and chocolate, is associated with many health benefits including improved insulin sensitivity (6). It is thought the flavanols activate nitric oxide, a vasodilator. The vasodilation, in turn, may help improve insulin sensitivity. In one study, researchers observed an increase in insulin sensitivity after consumption of flavanol-rich chocolate compared to flavanol-free chocolate (7). Subjects consumed 100 grams of flavanol-rich dark chocolate or 100 grams of flavanol-free white chocolate for 15 days. Those who consumed the flavanol-rich dark chocolate increased their insulin sensitivity (7). The flavanol-rich dark chocolate was also found to decrease blood pressure and improve flow-mediated dilation in individuals with essential hypertension (7). Another study in which subjects had a daily consumption of a high-flavanol (902 mg) cocoa or low-flavanol (36 mg) cocoa drink for 11 weeks also reported an increase in insulin sensitivity with chronic high-flavanol cocoa consumption (8). Yet another study concluded that cocoa ingestion improves insulin sensitivity in healthy individuals. (9). This study also showed a decrease in fasting insulin and glucose concentrations after the consumption of 100 grams (500 mg total polyphenols) dark chocolate, but not white chocolate (9). Although several studies show chocolate and cocoa ingestion improve insulin sensitivity, a two-week cocoa consumption study in which subjects with essential hypertension consumed a flavanol-rich (150 mL, 900 mg flavanols) cocoa drink twice a day did not show improvements in insulin sensitivity (13). More research is needed to examine the amount of flavanol-rich cocoa or chocolate needed as well as the period over which it should be consumed in order to observe an improvement in insulin sensitivity.
Reference List:
1. Davidovici, B. B. & Wolf, R. The role of diet in acne: facts and controversies. Clinics in Dermatology 28:12-16, 2010.
2. Williams, S., Tamburic, S., & Lally, C. Eating chocolate can significantly protect skin from UV light. Journal of Cosmetic Dermatology 8:169-173, 2009.
3. Heinrich, U., Neukam, K., Tronnier, H., Sies, H., & Stahl, W. Long-term ingestion of high flavanol cocoa provides photoprotection against UV-induced erythema and improves skin condition in women. J Nutr. 136(6): 1565-1569, 2006.
4. Gibson, S. & Williams, S. Dental caries in pre-school children: associations with social class, tooth brushing habit and consumption of sugars and sugar-containing foods. Further analysis of date from the National Diet and Nutrition Survey of children aged 1.5-4.5 years. Caries Res. 33(2): 101-13, 1999.
5. Matsumoto, M., Tsuji, M., Okuda, J., Sasaki, H., Nakano, K., Osawa, K., Shimura, S., & Ooshima, T. Inhibitory effects of cacao bean husk extract on plaque formation in vitro and in vivo. Eur J Oral Sci. 112(3): 249-52, 2004.
6. Corti, R., Flammer, A. J., Hollenberg, N. K., & Lüscher, T. F. Cocoa and cardiovascular health. Circulation 119:1433-41, 2009.
7. Grassi, D., Desideri, G., Necozione, S., Lippi, C., Casale, R., Properzi, G., Blumberg, J., & Ferri, C. Blood pressure is reduced and insulin sensitivity increased in glucose-intolerant hypertensive subjects after 15 days of consuming high-polyphenol dark chocolate. J Nutr. 138: 1671-76, 2008.
8. Davison, K., Coates, A. M., Buckley, J. D., & Howe, P. R. C. Effect of cocoa flavanols and exercise on cardiometabolic risk factors in overweight and obese subjects. Int J of Obes 32: 1289-96, 2008.
9. Grassi, D., Lippi, C, Necozione, S., Desideri, G., & Ferri, C. Short-term administration of dark chocolate is followed by a significant increase in insulin sensitivity and a decrease in blood pressure in healthy persons. Am J Clin Nutr 81:611-14, 2005.
10. Taubert, D., Berkels, R., Roesen, R., & Klaus, W. Research letters: chocolate and blood pressure in elderly individuals with isolated systolic hypertension. JAMA 290: 1029-30, 2003.
11. Balzer, J., Rassaf, T., Heiss, C., Kleinbongar, P., Lauer, T., Merx, M., Heussen, N., Gross, H. B., Keen, C. L., Schroeter, H., & Kelm, M. Sustained benefits in vascular function through flavanol-containing cocoa in medicated diabetic patients. A double-masked, randomized, controlled trial. J Am Coll Cardiol 51(22): 2141-49, 2008.
12. Hodgson, J. M., Devine, A., Burke, V., Dick, I. M., & Prince, R. L. Chocolate consumption and bone density in older women. Am J Clin Nutr 87:175-80, 2008.
13. Muniyappa, R., Hall, G., Kolodziej, T. L., Karne, R. J., Crandon, S. K., Quon, M. J. Cocoa consumption for 2 wk enhances insulin-mediated vasodilatation without improving blood pressure or insulin resistance in essential hypertension. Am J Clin Nutr 88:1685-96, 2008.