Perkins researchers hoping to demonstrate improved cardiovascular function among coffee lovers have found that drinking too much of the popular brew may actually be linked to worsening of the metabolic syndrome.
The study by Perkins researchers and researchers from the University of Western Australia's School of Medicine and Pharmacology into a compound found in coffee, known as Chlorogenic Acid (CGA), has been published in a respected United States journal.
"Studies have shown that coffee consumption lowers the risk of developing type 2 diabetes," said the University of WA's Professor Kevin Croft. "This also included research on decaffeinated coffee, which suggested that the health benefits are from a compound in coffee apart from caffeine.
"With this in mind, we studied the effects of Polyphenols, or more specifically CGAs, which are very rich in coffee but also found in tea and some fruits including plums. The CGAs were previously known for their health benefits, increasing insulin sensitivity and reducing blood pressure and body fat accumulation," he said.
"However, this study proved the opposite in dosages equivalent to five or six cups of coffee per day," said Perkin's Assistant Professor Vance Matthews.
The researchers found that the equivalent dose of CGA fed to laboratory mice affected the utilisation of fat in the liver and caused abnormal retention of fat within cells. The obese mice also had a tendency for a higher degree of glucose intolerance and increased insulin resistance.
Assistant Professor Vance Matthews said that it was still okay for people to drink moderate amounts of coffee.
"It seems that the health effects are dose-dependent. 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," he said.
"Everybody knows about the effects of caffeine, but when we're considering our lifestyle choices it's important to remember that compounds such as CGA can have an effect on our health if they're not consumed in moderation."
The researchers also found that CGA doesn't prevent weight gain in obese laboratory mice fed a high-fat diet when used at higher doses.
"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, Professor Croft said.
The collaborative study, "Supplementation of a High-Fat Diet with Chlorogenic Acid Is Associated with Insulin Resistance and Hepatic Lipid Accumulation in Mice" is published in the Journal of Agricultural and Food Chemistry.