Coffee and green and black tea are bursting with antioxidants, natural compounds that have been linked to a number of health benefits.
But the caffeine present in those beverages may also offer its own benefits, including reducing the risk of type 2 diabetes, suggests a new genetic study. This is possibly due to the effect of caffeine on body fat and weight.
“Our … finding suggests that caffeine might, at least in part, explain the inverse association between coffee consumption and risk of type 2 diabetes,” write the researchers. Caffeine linked to lower type 2 diabetes risk
The results of the new study fit with other research suggesting a link between caffeine and type 2 diabetes risk.
Earlier studies showed that moderate coffee consumption (three to five cups per day) is associated with a lower risk of type 2 diabetes and cardiovascular disease Trusted Source.
Another study found that caffeine intake results in a reduction in body fat. Excess weight is a risk factorTrusted Source for type 2 diabetes.
However, these studies weren’t designed to tease apart the potential effects of caffeine from those of antioxidants.
To overcome this limitation, the authors of the new study used a genetic method called Mendelian randomizationTrusted Source to examine the impact of blood levels of caffeine on body fat and on the risk of type 2 diabetes and cardiovascular disease outcomes.The cardiovascular outcomes they looked at included coronary artery disease, stroke, heart failure, and irregular heart rhythm (atrial fibrillation). The new study was published March 14 in BMJ Medicine.
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For the Mendelian randomization, researchers focused on two common genetic variants for two genes associated with how quickly the body metabolizes ingested caffeine.
People who carry the genetic variants associated with slower metabolism of caffeine drink less coffee, on average. However, they have higher levels of caffeine in their blood compared to people who metabolize caffeine more quickly.
For this study, the researchers examined genetic and other data from nearly 10,000 people of predominantly European ancestry who were taking part in six long-term studies.
They found that people who were genetically predisposed to have higher levels of caffeine in their blood were more likely to have a lower body mass index (BMI) and body fat.
In addition, they had a lower risk of type 2 diabetes. Researchers estimated that about half of the reduced diabetes risk was due to the lower BMI.
In contrast, no link was seen between genetically predicted caffeine levels in the blood and risk of cardiovascular disease outcomes.
One limitation of the study is that it included data mainly from people of European ancestry, so the results may not apply to other groups.
In addition, researchers looked at only two genetic variants associated with caffeine metabolism. Other variants might also shape a person’s type 2 diabetes risk in relation to their caffeine intake.
Too early for ‘prescribing’ caffeine. The results of the new study support the link between caffeine intake and a lower risk of type 2 diabetes.
But Dr. Denise Pate, an internal medicine physician and medical director with the Medical Offices of Manhattan in New York City, pointed out that researchers did not look specifically at the link between caffeine metabolism and blood glucose levels, which is how type 2 diabetes is diagnosed.
Still, some research suggests possible ways in which caffeine might reduce the risk of type 2 diabetes.
“Caffeine works as a thermogenic, meaning that it increases energy expenditure — you can think of it as micro-exercise,” said Pate.
In addition, “caffeine has the properties of increasing satiety, meaning it suppresses the desire to eat, therefore leading to a lower BMI,” she said.
