A coffee and a cup of tea, black or green, have one thing in common, their caffeine content. Well, it is precisely the caffeine that makes these drinks precious allies in reducing the risk of overweight and type 2 diabetes. This emerges from a very recent scientific research published in the journal BMJ Medicine and performed thanks to the collaboration between Swedish, British and Danish scientists ( Larsson et al, BMJ Medicine, 2023).
Tea and coffee, health benefits
Tea and coffee are protective for health. From previous studies, we know that they have a powerful hypoglycemic action and help to counteract the damage that high blood sugar levels can cause to the body's organs, such as the kidneys. Not only that, these properties are also reflected in a cardioprotective action. But which substances are responsible for these beneficial effects? It has been speculated that caffeine may play a role. In fact, caffeine has a thermogenic action, namely it stimulates the production of heat starting from fat accumulations, useful for keeping body weight under control and counteracting overweight. Therefore, caffeine can help reduce the risk of diseases associated with adiposity, such as type 2 diabetes. However, until now, this was only a hypothesis and no research has been able to indicate caffeine as the beneficial substance useful in counteracting overweight and type 2 diabetes. This is because both coffee and tea contain other substances, such as antioxidants, to which important anti-inflammatory and anti-free radical properties are attributed. In addition, the long-term effects of tea and coffee intake were not known. However, the research we are talking about today managed to fill these gaps. But let's go in order and try to understand better.
Caffeine fights overweight and type 2 diabetes, the study
Scientists have used a technique, called Mendelian randomization, to try to understand the role of caffeine in influencing the health of the body. This special scientific technique studies genetic variations to determine how modifiable factors can generate effects in the body. In our case, the modifiable factors are represented by the intake of drinks, tea or coffee, containing caffeine. Researchers have isolated specific genetic variations related to how the body metabolizes caffeine. In particular, in some people caffeine is metabolized more slowly than others and in these people the levels of caffeine in the blood are higher. Then, the researchers used these genetic variations to understand the effects of caffeine on body weight and the risk of developing type 2 diabetes. The scientists then drew on the genetic and health data of nearly 10,000 people, all participants in long-term studies. Well, what emerged is that those who presented the genetic variation that indicated a slow metabolism of caffeine and had higher levels of this substance in their blood also had a lower body mass index and a reduced accumulation of fat. Not only that, these people also had a reduced risk of developing type 2 diabetes, it is believed largely due to the anti-obesity action of caffeine.
The study is very interesting as it shows that well-known and appreciated beverages, such as non-decaffeinated coffee and tea, can also help to counteract being overweight and all the ailments that may follow from it, such as type 2 diabetes. If you consider that, as demonstrated by another recent scientific research, the increase in blood sugar can increase the risk of developing Alzheimer's, then the results are even more significant (Roeder et al, Nature Structural and Molecular Biology, 2020). The important thing, however, is not to overdo it and include tea and coffee as part of a varied and balanced diet, without excesses. In fact, even too much caffeine can be harmful, causing anxiety, irritability, but also nausea, tremors and palpitations. Not only that, it is also important to drink tea and coffee without adding sugar so as not to add extra calories that would counteract the beneficial effect of these drinks.