Some chemicals in coffee play a positive role in metabolism.

Coffee drinking is not associated with chronic diseases such as heart disease, cancer and Ⅱ diabetes, and regular coffee drinkers are less likely to develop Ⅱ diabetes, according to a German study.

Previous studies on coffee and health have shown conflicting results, with some studies showing that drinking coffee regularly increases the risk of heart disease, cancer and stroke.

To further study the relationship between coffee and health, researchers at the German Institute for Human Nutrition followed more than 42000 German adults for nearly 10 years. At the beginning of the study, none of the subjects had chronic diseases, and the researchers learned about their coffee drinking habits, diet, exercise, physical condition and so on.

Over the next nine years, the researchers collected information every two or three years, focusing on the health of the subjects, especially cardiovascular and cerebrovascular diseases, stroke, heart disease, diabetes and cancer.

According to the data, of the 8689 people who did not drink coffee, 871 developed a chronic disease, while 1124 of the 12137 people who drank at least four cups of coffee a day developed a chronic disease, with a prevalence rate of about 10 per cent. In other words, there is no significant difference in chronic diseases between regular coffee drinkers and infrequent coffee drinkers.

"our research shows that coffee drinking in healthy adults does not cause some major chronic diseases," Anna Froger, an epidemiologist who led the study, was quoted by Reuters as saying on March 1. "

The study was published in the latest issue of the American Journal of Clinical Nutrition. Rob Fan Dan, a professor at the National University of Singapore, was not involved in the study. "We are not encouraging people who do not like coffee to start drinking it, but the evidence about coffee and health suggests that coffee lovers without special circumstances do not have to drink less coffee in order to reduce the risk of chronic diseases," he said. "

The researchers also found that coffee drinkers were less likely to develop Ⅱ diabetes than non-coffee drinkers. The data showed that 3.2% of respondents who drank four cups of coffee a day later developed Ⅱ diabetes, while those who did not drink coffee had Ⅱ diabetes at 3.6%.

Ⅱ type diabetes, also known as adult-onset diabetes, more than 90% of patients belong to this type, which is characterized by insensitivity to insulin. In addition to genetic factors, Ⅱ diabetes is associated with unhealthy diet and lifestyle.

Taking into account factors such as weight and smoking, the researchers determined that regular coffee drinkers were 23 per cent less likely to develop diabetes than non-coffee drinkers. This ratio is consistent with some other research data.

The researchers say this does not mean that drinking coffee can prevent Ⅱ diabetes, but some animal experiments have shown that some chemicals in coffee play a positive role in metabolism.