Coffee is one of the world’s favorite drinks: per year we consume 10,000 kg of this grain. This has led to the infusion becoming the subject of numerous scientific studies to find out its effects on health. The latest of these analyzes has linked the drink to a lower risk of type 2 diabetes.
Coffee and type 2 diabetes. A new study has pointed to caffeine as responsible for the correlation between coffee consumption and a lower risk of type 2 diabetes. The amount of body fat could be another of the mediating variables in this relationship according to the work.
The study team found that high levels of caffeine in the blood were correlated with a lower body mass index, as well as a lower risk of type 2 diabetes.
Mendelian randomization. The study has recently been published in the journal BMJ Medicine. In the article, the team of researchers responsible for the study details the mechanism they used to determine the link between the most consumed stimulant in the world and health: Mendelian randomization.
The process is based on using genetic variability to establish causal relationships between correlated variables. To do this, the researchers took variants of two genes, CYP1A2 and AHR, in a sample of 10,000 participants in population studies. The genetic variations were selected for their relationship to how we metabolize caffeine, causing some people to retain the substance longer in their bodies.
Overcoming limitations. With this methodology, we try to overcome some limitations of observational studies, those that are done outside of a controlled experimental environment such as laboratory experiments or randomized controlled trials.
Even so, the researchers drew attention to some issues that future studies on the subject will have to resolve, such as the low diversity of the sample analyzed (predominantly of European descent) or the fact that the study only focused on two genes. Another mechanism to consolidate knowledge would be to resort to controlled clinical studies similar to those carried out to analyze the effects of drugs and treatments.
“These discoveries offer an important improvement in understanding the potential causal effect of caffeine on adiposity and diabetes risk. Even so, future clinical studies are necessary before individuals can use these results as a guide in their dietary preferences,” explained Dipender Gill, one of the study authors, in a press release.
It’s not just diabetes. It’s not the first study to link a lower risk of diabetes. In a previous work, Susanna Larsson (who also signs the present study) and Mattias Carlström observed that the relative risk of suffering type 2 diabetes decreased by almost 30% among the highest coffee consumers. The decrease was 6% in the case of decaffeinated consumers.
Studies on the salutogenic properties of coffee go beyond diabetes. Although it should be noted that this last analysis did not observe an improvement in cardiovascular health as an effect of coffee consumption, it was observed in other analyses.
A review of the scientific literature on the subject carried out a few years ago found a decrease in general and cardiovascular mortality linked to coffee consumption. The problem with the studies carried out to date (such as those included in this review) is that they are observational studies in which it is more difficult to control different variables.
Benefits with limits. There are some issues that need to be taken into account. One of them is the possibility that other drinks besides coffee could have the same effects. The study does not analyze, for example, the effects of other infusions on health. Energy drinks are also high in caffeine, but the abundance of sugar would dilute any potential benefits of their stimulant.
To this we must add that excessive caffeine consumption can be dangerous. The recommended daily limit of this substance is around 400 mg per day, which would be approximately equivalent to the consumption of one liter or four cups of coffee.
The limit may be even lower for some population groups such as adolescents (recommended maximum of 100 mg per day) or pregnant women (recommended maximum of 200 mg per day). In any case, we will have to wait for more studies and prioritize a varied and healthy diet as the best mechanism in the prevention of diabetes.
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Image | Nathan Dumlao