A study links higher levels of caffeine in the blood with a lower risk of diabetes and being overweight

Food is one of the favorite topics for lovers of dialectical brawl, perhaps because it is not easy to determine who is right.

Coffee is, after water, the most consumed liquid in the world, and around this drink there is intense discussion.

This week, an international team of researchers led by Susanna Larsson, from the Karolinska Institutet in Stockholm (Sweden), publishes a study in the journal

that can be used by those who want to drink coffee, not only with a clear conscience, but even with a certain sense of moral superiority.

Larsson and his colleagues conclude that high levels of caffeine in the blood can reduce a person's amount of body fat and their risk of type 2 diabetes, which is associated with aging and certain lifestyle habits.

The results are consistent with those of many observational studies that, going back decades, have seen a relationship between coffee consumption and a lower risk of diabetes.

In an article published in 2018 by the same Larsson, it was estimated that with each cup of caffeinated coffee taken per day the risk of developing diabetes was reduced by 7%, a benefit that, with 6%, was almost equal to that of coffee. decaffeinated.

Another study carried out by scientists from the World Health Organization (WHO) in 2017, calculated that three coffees a day reduce premature mortality between 8 and 18%.

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Despite the accumulation of positive results, these observational studies do not make it possible to ensure that the links detected are causal.

In 1991, the WHO put coffee on the list of possible carcinogens and, years later, reversed the decision when it was found that the higher incidence of cancer among coffee growers could be explained by other associated habits, such as the cigarette that sometimes accompanies coffee. that drink.

The authors of this paper recall that no randomized trials have been carried out, which are very expensive and complex to carry out, with which causality can be established, to analyze the effect of caffeine on the development of diabetes or cardiovascular disease.

Coffee genetic variants

To at least partially overcome these limitations, the scientists used a novel method, known as Mendelian randomization, which uses genetic variations with a known function to assess the causal effect of a risk factor.

In this case, they analyzed the CYP1A2 and AHR genes, which determine the speed at which our body processes caffeine, in 10,000 people.

Individuals with genetic variants that cause caffeine to remain in the blood longer tend to drink less coffee, because they feel a longer stimulation, but have higher concentrations of caffeine in their blood plasma.

The observed effect is not large enough individually to consider drinking coffee to prevent diabetes

Gemma Rojo, Regional University Hospital of Malaga

With this approach, which tries to separate the effect of caffeine in the blood on obesity or diabetes from other factors related to coffee consumption, they observed that people with genetic variants that slow down the processing of caffeine and favor its greater presence in the blood they had a lower body mass index and a lower percentage of fat.

The main reason for the reduction in the risk of diabetes, to which 43% of the effect is attributed, is weight loss, caused by its ability to speed up metabolism and reduce appetite, among other qualities.

Gemma Rojo, a researcher at the Hospital Regional Universitario de Málaga, considers that the study is interesting, but recalls "that the observed effect is not individually so great as to consider drinking coffee to prevent diabetes, and that to a person who already has diabetes, It won't help you control it, because it won't lower your blood sugar levels."

"One reading that can be done is that the evidence for the benefits of coffee is greater than the one we have against it, but the effect of coffee on diabetes is better seen at the population level and is not very useful for making individual decisions," rivet.

The authors of the study published today in the journal

They believe that, given their results, it would be interesting "to carry out randomized studies to see if caffeinated and calorie-free beverages may play a role in reducing the risk of obesity and type 2 diabetes."

Jorge Ferrer, head of the Genomic Regulation and Diabetes group at the CRG in Barcelona, ​​thinks that this approach is excessive "taking into account that this study has not taken into account other variables, such as mental well-being or how caffeine affects quality of the dream”.

However, he does consider this type of Mendelian randomization study useful to obtain information that is very difficult to obtain about caffeine, "following many people for several years, giving some caffeine and others a placebo" and controlling for many other variables.

As with almost everything that has to do with diet, a positive effect of caffeine for your energy intake does not imply a magic solution to lose weight or prevent chronic diseases such as diabetes.

Eating less and better and exercising more are still the most effective solutions.

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