German researchers report in the American Journal of Clinical Nutrition that consuming at least four cups of coffee per day was associated with a 23–30% lower risk of type 2 diabetes, compared with people consuming less than one cup per day.
In an accompanying editorial in the same journal, Esther Lopez-Garcia from Universidad Autonoma de Madrid said that coffee has a very complex composition, and that many of the compounds it contains have been reported to exhibit biological effects.
“For example, phenolic compounds in coffee (chlorogenic acid, ferulic acid, p-coumaric acid), magnesium, trigonelline, and quinides have been associated with improved insulin sensitivity,” wrote Lopez-Garcia.
"Phenolic compounds also have antioxidant activity. In addition, diterpenes in coffee (cafestol and kahweol) have anticarcinogenic properties. Thus, it is plausible that the harmful effects of caffeine could be offset by the beneficial effects of these other components.”
A meta-analysis published in the Archives of Internal Medicine in 2009 concluded that consumption of three to four coffee may reduce the risk of developing diabetes by 25%. The potential bioactive compounds in the beverage responsible for the reported benefits may include magnesium, antioxidant lignans or chlorogenic acids.
According to the World Health Organisation (WHO), diabetes affects over 220 million people globally and the consequences of high blood sugar kill 3.4 million every year. The WHO is predicting deaths to double between 2005 and 2030.
The total costs associated with the condition in the US alone are thought to be as much as $174 billion, with $116 billion being direct costs from medication, according to 2005-2007 American Diabetes Association figures.
Led by Anna Floegel from the German Institute of Human Nutrition Potsdam-Rehbruecke, the researchers analyzed data from 42,659 people.
Over nine years of study, during which data was collected every 2-3 years, the researchers documented 1,432 cases of type-2 diabetes, 394 hearts attacks, 310 strokes, and 1,801 cases of cancer.
There was no link between coffee consumption and the incidence of heart disease, nor the risk of cancer. There was also no difference in the results when they considered caffeinated and decaffeinated coffee independently.
The highest intake of caffeinated coffee (at least four cups per day) was associated with a 23% decrease in the type-2 diabetes, while the same intake of decaf was associated with a 30% decrease.
In her editorial, Lopez-Garcia concluded: “Although more research on the health effect of coffee is yet needed to formulate sound recommendations on its consumption, current information suggests that coffee is not as bad as we were told.”
Source: American Journal of Clinical Nutrition
2012, Volume 95, Pages 901-908
“Coffee consumption and risk of chronic disease in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Germany study”
Authors: A. Floegel, T. Pischon, M.M. Bergmann, B. Teucher, R. Kaaks, H. Boeing
Editorial: American Journal of Clinical Nutrition
2012, Volume 95, Pages 787-788
“Coffee consumption and risk of chronic disease: changing our views”
Author: E. Lopez-Garcia