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Caffeine, an Ally in Moderate Doses

Since caffeine is the most consumed psychoactive substance in the world, its effects on the brain have always been the source of many concerns and fictions. For the past two decades, research has focused on understanding the effects of caffeine at doses that correspond to average consumption, such as between 2 and 5 cups of coffee per day. "Even though it's always difficult to study elements of our diet, we get more realistic results because many factors come into play, particularly chronobiology," emphasizes health researcher Astrid Nehlig.

#Coffee remains the main source of caffeine in the world, but it is not the only one and its main effect, increased alertness, lies behind its use. Legend has it that an African shepherd who noticed that his goats were agitated after eating coffee tree seeds reported his observation to neighboring monks, who in turn devised a drink that could keep them awake during their long hours of prayer.

#Caffeine has the ability to bind to the adenosine receptors of our neurons, preventing neurons from playing its role in reducing their activity and promoting sleep. Therefore, it is not surprising that coffee consumption disrupts sleep even after a few hours. If the effects on wakefulness are felt between 10 minutes and an hour after ingestion, it takes about six hours for the body to excrete half of the caffeine: a cup of coffee after 5 pm can interfere with restful sleep. there is a genetic polymorphism of adenosine receptors, which explains why it is not affected", he analyzes. Neuronal activity enhanced by inhibition of adenosine receptors can cause an increase in adrenaline production to improve the body's ability to respond to what it perceives as increased activity, with potential repercussions on the dopamine circuitry.

All these effects on neurotransmitters raise the issue of habituation and addiction, supported by the withdrawal syndrome observed by some coffee consumers. "Other than this withdrawal effect, which is found in 10% of people and lasts from 48 hours to a week, the most important markers of addiction are not activated by caffeine consumption," says Astrid Nehlig. Thus, a reliable study did not show a spontaneous increase in morning caffeine dose that always had the same effect, and the reward-effect-dependent addiction circuitry that is typical of addictions is not active at all.

While no physiological dependence on caffeine can be attributed, the researchers do not rule out psychological dependence due to the convenience of better alertness or increased intellectual performance thanks to caffeine's ability to concentrate. However, studies have shown a possible addiction to some of the negative effects of caffeine: irritability, anxiety, muscle restlessness. These particularly troublesome effects normally lead to self-limiting of caffeine consumption, but if these warning signs go away, what are the long-term effects of excessive coffee consumption?

Currently, the most reliable studies involving the largest number of people show that low to moderate caffeine consumption of less than 5 cups per day has no significant adverse health effects. That's why recommendations of international health organizations include this figure, which is reduced to 2 or 3 glasses a day for pregnant women. These data appear to correspond to the average consumption observed in most Western countries, but this is only an average figure for the entire population.


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