According to research, having high levels of caffeine in your blood can reduce the amount of body fat you carry and lower your risk of type 2 diabetes.
The findings could lead to the use of calorie-free caffeinated drinks to reduce obesity and type 2 diabetes, although more research is needed, the researchers wrote in the journal BMJ Medicine.
Dr Katarina Kos, senior lecturer in diabetes and obesity at the University of Exeter, said research has shown potential health benefits for people with high levels of caffeine in their blood, but said added: “It does not study or recommend drinking more coffee, which was not the purpose of this research.
She said any caffeinated drink that contains sugar and fat will outweigh the positive effects.
The researchers said their work built on previously published research, which suggested that drinking three to five cups of coffee a day, containing an average of 70 to 150 mg of caffeine, was associated with a lower risk of diabetes. type 2 and cardiovascular disease.
Because these were observational studies, it was difficult to determine whether the effects were due to caffeine or other compounds, the researchers said.
This latest study used a technique known as Mendelian randomization, which establishes cause and effect through genetic evidence. The team found two common genetic variants associated with the speed of caffeine metabolism and used them to determine genetically predicted blood caffeine levels and whether this was associated with lower BMI and lower body fat.
People with genetic variants associated with slower caffeine metabolism drink less coffee on average, but have higher blood levels of caffeine than people who metabolize it quickly.
The researchers found that nearly half of the reduced risk of type 2 diabetes was due to weight loss. Caffeine is known to boost metabolism, increase fat burning and reduce appetite, with a daily intake of 100mg estimated to increase energy expenditure by approximately 100 calories per day.
There are limitations to the findings, including the fact that the research was based on nearly 10,000 people of mostly European ancestry, who took part in six long-term studies.
Dr Stephen Lawrence, associate clinical professor at the University of Warwick Medical School, said the study was “interesting” and used “good science”, but noted that the Mendelian assessment was a ” relatively new technique” and, although useful, was “vulnerable to bias”.
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He said this could lead to future studies that could eventually develop promising treatments. “It represents good science forming hypotheses or ideas. However, this does not prove cause and effect. We must therefore be careful not to rush into over-interpretation.
The authors took a “great leap of faith” in assuming that the weight loss caused by increased caffeine consumption would reduce the risk of developing type 2 diabetes, Lawrence said, adding that it was no more effective than reduce caloric intake and increase physical activity. . Also, caffeine consumption gave some people palpitations and abnormal heart rhythms, so it was not for everyone.
He said: “Should people drink more coffee to reduce the risk of fat or diabetes? Science suggests relatively strong evidence that caffeine consumption increases fat burning, even at rest. However, it is not a treatment for obesity and, if used incorrectly, can lead to weight gain and even harm.