Coffee is the most consumed beverage worldwide after water, and perhaps for this reason, its potential benefits and drawbacks have been discussed for years. The results of some studies indicate that the components of coffee can help prevent neurodegenerative diseases, such as dementia, and its intake has also been related to a lower risk of developing liver cancer or endometrial cancer, or with protection against diseases cardiovascular.
A new study supports the positive effects of coffee, as it has linked high levels of caffeine in the blood with a reduction in weight and body fat and with a lower probability of suffering from type 2 diabetes. The work has been carried out by an international team of researchers led by Susanna C. Larsson of the Institute of Environmental Medicine at Stockholm University, Sweden, and their findings have been published in the British Medical Journal.
The aim of the research was to find out the long-term effects of caffeine concentrations in the blood on the accumulation of body fat (adiposity), type 2 diabetes and major cardiovascular diseases. The researchers used the method of Mendelian randomization with genetic variants of almost 10,000 people to analyze the BMI (body mass index) and health problems such as type 2 diabetes, ischemic heart disease, atrial fibrillation, heart failure and cardiovascular events.
The results have shown that higher concentrations of caffeine were associated with lower BMI and fat mass and less risk of developing type 2 diabetes. They also indicate that about half of the effect of caffeine on type 2 diabetes is related to the decrease in body mass index, although the study authors have stressed that long-term clinical trials are necessary to confirm the findings.
Genetics influences whether you are more or less coffee
The Mendelian randomization method used in this study uses genetic variations with a known function to assess the causal effect of a risk factor. The researchers analyzed the CYP1A2 and AHR genes – which determine the speed at which the body processes caffeine – in 10,000 people. Individuals with genetic variants that cause caffeine to stay longer in the bloodstream tend to drink less coffee, but have higher concentrations of caffeine in their blood plasma.
The researchers found that higher genetically determined levels of caffeine in the blood were associated with lower weight and body fat and less risk of type 2 diabetes, and that weight loss promoted nearly half (43%) of the effect of caffeine on the risk of type 2 diabetes. They acknowledge, however, that the work has limitations, such as having used only two genetic variants and that all the participants are of European descent.
“Our Mendelian randomization finding suggests that caffeine could explain, at least in part, the inverse association between coffee consumption and type 2 diabetes risk,” they wrote. Randomized controlled trials are warranted to assess whether non-caloric caffeine-containing beverages might contribute to reducing the risk of obesity and type 2 diabetes,” they conclude.
“The results would somehow support the known protective effect of moderate coffee consumption on the risk of suffering and dying from the main non-communicable diseases (cancer, cardiovascular, diabetes), also evidenced in Spanish cohort studies. However, some important aspects remain unclear, such as to what extent the plasma level represents regular caffeine consumption and what proportion is due to coffee consumption or other foods such as chocolate or caffeinated sugary drinks that also contain other nutrients unhealthy” has declared to SMC Spain Jesús Vioque, professor of Preventive Medicine and Public Health and director of the Nutrition Epidemiology Unit of the Miguel Hernández University of Elche.
“The genetic study shows links and potential health benefits for individuals with certain genes that are attributed to faster coffee metabolism as an inherited trait, and potentially better metabolism. It does not study or recommend drinking more coffee, which was not the objective of this research. And, most importantly, when considering the consumption of coffee and caffeine-containing energy drinks, one must take into account the potential negative trade-off for excess calories in the form of sugar and fat from many of these drinks. Even for the option of increasing the use of calorie-free caffeinated beverages, a benefit has not yet been shown,” says Katarina Kos, Senior Lecturer in Diabetes and Obesity at the University of Exeter (United Kingdom), in statements to the same outlet.
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