March 17, 2023 — Having higher blood levels of caffeine may reduce body fat and the risk of type 2 diabetes. new study is published BMJ Medicine.
Although more research is needed, the findings offer insight into the role that calorie-free caffeinated beverages may play in reducing the risks of obesity, diabetes and other conditions.
“Caffeine affects metabolism and is commonly used in beverages. So it’s important to better understand what cause and effect it might have on metabolism,” said senior study author Dipender Gill, PhD, professor of epidemiology at Imperial College London.
“However, we would like to emphasize that individuals should not change their dietary preferences or lifestyle based on the results of our study alone,” he said. “Further validation in the form of clinical trials is first warranted. Furthermore, too much caffeine can also have harmful effects, so a balance is needed.”
Previous studies have shown that drinking 3 to 5 cups of coffee a day is associated with a lower risk of type 2 diabetes and heart disease, and drinking 100 milligrams of caffeine a day can increase energy expenditure by about 100 calories a day. An average cup of coffee contains about 70-150 milligrams of caffeine.
However, most published research focuses on observational studies that do not prove cause and effect. Many other factors may be involved, including other ingredients in caffeinated beverages and foods, according to lead author Susanna C. Larsson, PhD, of the Karolinska Institute in Stockholm, Sweden, and colleagues.
Katarina Kos, MD, PhD, senior lecturer in diabetes and obesity at the University of Exeter in the UK, agrees. He said this genetic study “shows associations and potential health benefits for people with certain genes that are attributed to faster [caffeine] metabolism as an inherited trait and potentially better metabolism”.
“It does not examine or recommend drinking more coffee, which was not the purpose of this study,” he said told the UK Science Media Centre. Kos was not involved in this study.
In the new analysis, researchers looked at data from 10,000 people, mostly of European descent, who participated in six long-term studies.
They studied two specific genetic mutations associated with a slower rate of caffeine metabolism. In general, people with these two common genetic variants will have higher levels of caffeine in their blood after consuming coffee or other caffeinated beverages than those with faster caffeine metabolism.
They then looked at how caffeine levels correlated with body fat, type 2 diabetes and serious heart conditions such as coronary artery disease, stroke, heart failure and irregular heart rhythms.
The two gene variants led to “genetically predicted higher lifetime plasma caffeine concentrations,” the researchers noted, “and were associated with lower risk of body mass index and fat mass, as well as type 2 diabetes.”
In this study, there was no strong association with a lower risk of developing any of the major heart diseases.
They found that weight loss accounted for about 43% of caffeine’s effect on type 2 diabetes risk.
“The finding that higher plasma caffeine levels can reduce body weight and risk of type 2 diabetes appears to be consistent with what is known about its effects on metabolism,” Gill said. “We are now investigating the broader effects of caffeine on health outcomes and potential mechanisms that may mediate this.”
The researchers noted several limitations, including that they only looked at two genetic variants and that the study participants were mostly of European descent. They also emphasized caution in drawing strong conclusions or changing behavior.
Kos agrees. “When discussing coffee consumption and caffeinated energy drinks, one must keep in mind the potential negative compensation of excess calories from sugar and fat in many of these beverages,” he said.
“Even with the option of increasing consumption of calorie-free caffeinated beverages, the benefit has yet to be proven,” Koss said.