Men should not drink more than three cups of coffee a day.

Now, coffee has become a fashionable drink, more and more cafes are open, young people like to go to cafes for parties, and coffee has become a must-have drink for many families. However, health experts advise those who like to drink coffee and those who are very sociable not to drink too much coffee and to drink two to three cups a day. In principle, no more than three cups of stimulating drinks are recommended.

Canadian researchers recently found that caffeine has a bad effect on people who don't have enough insulin. Researchers have found that caffeine has adverse effects on potential patients with type 2 diabetes, which may lead to type 2 diabetes. Type 2 diabetes is the most common diabetes in Canada, accounting for 90% of all diabetics.

American scientists have also found that smokers who drink three or more cups of coffee a day can quadruple their risk of developing pancreatic cancer. Caffeine has an adverse effect on normal cells, and it can promote cell aging. After epidemiological investigation and research, American scholars have confirmed that coffee is a potentially dangerous beverage and believe that caffeine has a non-negligible effect on the formation of pancreatic cancer. Coffee drinkers are 2-3 times more likely to develop pancreatic cancer than non-coffee drinkers. At present, about 20,000 people die of pancreatic cancer in the United States every year. At least half of them are caused by drinking coffee.

Researchers from Harvard University in the United States have found that people who drink coffee are more likely to develop bladder cancer, especially for women. If the risk of bladder cancer is set at 1 for those who drink only half a cup of coffee or not, then among those who drink more than three cups of coffee a day, the risk of bladder cancer is 1.31 for men and 2.19 for women. Japanese scientific research report also said that in some male patients with gastric cancer, many people like to drink coffee.

How can coffee cause cancer? At present, there are several speculations, one is that caffeine, the main component of coffee, plays a role in inducing tumors, and the other is that in the process of making coffee, opium poppy-like substances are produced, which are carcinogenic.

According to the results of earlier international studies, pregnant women who drink coffee or other caffeinated drinks are prone to miscarriage, and even if they do not have a miscarriage, their fetuses are likely to weigh less. However, the result is also controversial. Recent findings by Swedish researchers suggest that a small amount of coffee or other caffeinated drinks consumed by pregnant women may not do any harm to the fetus. Researchers at the Karolinska College of Medicine in Sweden reached this conclusion after investigating 900 pregnant women in the Uppsala region near the Swedish capital Stockholm. However, most researchers admit that pregnant women should not drink too much coffee.

Coffee contains caffeine ingredients, with mild central nervous stimulation, appropriate drinking can reduce fatigue, enhance memory, reasoning and intelligence, auditory and visual response also become sharp. At the same time, long-term absorption of excessive caffeine may lead to high blood pressure. It was reported that 19 volunteers had a certain increase in blood pressure after taking a 500 mg caffeine pill (the equivalent of five cups of coffee). Recently, the international medical community has also discussed the possible effects of coffee on health problems such as osteoporosis, high blood pressure, heart disease, weight loss, pregnancy and preterm birth.

Although caffeine is not an addictive "drug", experts believe that abstaining from caffeine should not be too sudden, lest it cause migraine-like problems or bad temper. To quit coffee, it is best to take a gradual approach, reducing a little every day until it is reduced to less than 3 cups. If you feel a headache during the reduction period, maintain the present amount for the time being, and continue to reduce the pain.