While research finds that drinking coffee in moderation can be good for your health, overdoing it isn’t. In a new study, Australian researchers have found that drinking more than five or six cups a day can lead to weight gain and boost your risk of metabolic syndrome.
Metabolic syndrome is a group of risk factors, such as large waist size, high blood pressure, and high triglyceride levels, that increase a person’s risk of developing chronic diseases, such as diabetes and stroke.
In the new study, researchers from the Western Australian Institute for Medical Research and the University of Western Australia's School of Medicine and Pharmacology looked specifically at the effects of polyphenols, or more specifically CGAs, which are very rich in coffee but also found in tea and some fruits including plums.
"Studies have shown that coffee consumption lowers the risk of developing type 2 diabetes," said professor and lead researcher Kevin Croft in a news release released May 26. "This also included research on decaffeinated coffee, which suggested that the health benefits are from a compound in coffee apart from caffeine."
In mice studies, the team found that the equivalent amount of CGAs in about five or six cups of coffee for humans made the mice retain fat in their cells. The obese mice also had a tendency for a higher degree of glucose intolerance and increased insulin resistance.
"It seems that the health effects are dose-dependent," said assistant professor Vance Matthew. "A moderate intake of coffee, up to three to four cups a day still seems to decrease the risk of developing diseases such as cardiovascular disease and type 2 diabetes."
Also, the mice study found that CGA didn’t promote weight loss.
"People might be wasting their money if they're buying expensive products like green coffee bean dietary supplements which are currently considered to be amazing weight loss products," Croft added.
The study appears online in the Journal of Agricultural and Food Chemistry.
A separate study published in March in the American Heart Association journal Stroke found that coffee and green tea can help cut the risk of suffering a stroke. The 13-year study included 82,369 men and women in Japan.