A rat study showed that mixing alcohol with energy drinks could lead to long-term damage to brain cognitive function.
Alcohol and energy drinks are popular among young people, whether it's for late-night parties or all-night study. Epidemiological data show that alcohol consumption among adolescents is on the rise these days. When people drink alcohol, they sometimes mix it with some energy drinks.
Energy drinks are similar to regular soft drinks (beverages that do not contain ethanol or contain less than 0.5% ethanol), but contain high concentrations of stimulants (e.g., caffeine) and other added ingredients (e.g., taurine and vitamins). Teenagers choose these drinks because they want to improve their concentration, stay awake, and regain their strength. However, little is known about the long-term effects that they may have on brain function when they are mixed together.
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In a paper published in Neuropharmacology, researchers from the University of Cagliari and the University of Catania in Italy found that mixing alcohol with energy drinks may cause long-term damage to the brain.
The researchers did an experiment: they had adolescent male rats "drink" (actually gavage) tap water, alcohol, an energy drink (Red Bull), or a mixture of both; After 53 days, they assessed the cognitive function of the four groups of rats using methods such as brain scans and behavioral tests.
In the study, the daily dose of ethanol in the drinking group of rats was 3.2 grams per kilogram of body weight, which is equivalent to a 70-kilogram person drinking 18~24 grams of ethanol; The Red Bull dosage for rats in the energy drink group was two cans of equivalent weight per kilogram of body weight, which is equivalent to a 70-kilogram person drinking two cans of Red Bull; In contrast, the doses administered to the rats in the mixed drink group were the sum of the two. According to previous research in The Lancet, the recommended alcohol intake for adults is no more than 18.7 grams of ethanol per day, regardless of region, age, gender or year. Thus, for the rats in the experimental group who "drank alcohol", their alcohol intake was already near the upper limit of this recommended value.
The researchers found that the rats in the mixed drink group experienced lasting changes in learning and memory, as well as changes in the hippocampus, an area of the brain responsible for learning and memory. In particular, hippocampal plasticity appears to be affected, impairing the brain's ability to adapt and change to new information and needs. And this is a vital part of the normal functioning of the brain.
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At first, these rats, who consumed both alcohol and energy drinks, experienced an increase in specific brain markers and functions. Neurons in these rats expressed more brain-derived neurotrophic factor (BDNF) in the short term than in the control group. This protein interacts with tropomyosin receptor kinase B (trkB) to promote the growth of neurons in the hippocampus and other regions, which aids learning and memory. Unfortunately, this benefit is not long-lasting. Over time, by the time the rats reach adulthood, the expression levels of both proteins will decrease significantly, and brain function will decline dramatically.
The main molecular mechanism of learning and memory is the long-term potentiation (LTP) of the hippocampus, that is, the phenomenon that presynaptic neurons are rapidly formed in postsynaptic neurons after being stimulated rapidly and repeatedly for a long time.
Based on this, neurons before and after synapses are able to encode new long-term memories and store them in the brain. This is where the synaptic plasticity of hippocampal neurons comes in. At the molecular level, presynaptic neurons secrete glutamate, which binds to receptors in postsynaptic neurons, stimulating more receptors to migrate to neuronal cell membranes, thereby strengthening intersynaptic connections.
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According to the results of the study, there was initially an increase in hippocampal LTP in both the energy drink and mixed drink groups, which is consistent with the increased levels of BDNF protein measured by the researchers. In adulthood, LTP was significantly reduced in all three experimental groups, suggesting that long-term intake of these beverages during adolescence would impair the brain's memory function.
Studies have pointed out that caffeine in energy drinks is an adenosine receptor antagonist, and long-term intake of caffeine will cause a significant decrease in LTP, which may be caused by the up-regulation of adenosine receptor feedback expression after caffeine blocks the action of adenosine. Another possibility is that caffeine down-regulates the expression levels of BDNF proteins.
"Our results show that when alcohol is mixed with energy drinks around the time of puberty, there are adaptive changes at the electrophysiological and molecular levels in the brain hippocampus," the researchers wrote. This is associated with changes in behaviour and begins to manifest during adolescence and continues into adulthood. ”
However, further research is needed to determine the consequences of drinking a mixture of alcohol and energy. It is important to note that there may be gender differences in the effects of alcohol on the human central nervous system, perhaps because the hormones produced by the gonads and their neuroactive metabolites are able to regulate many of the nerve conduction systems associated with the alcohol response. Alcohol is inherently harmful to health, and it's obvious that mixing these two drinks together in any way is not a good idea.
Overall, the results of this study suggest that the consequences of adolescents mixing alcohol and energy drinks may not be the result of drinking alcohol and energy drinks alone. It may permanently affect the plasticity of the hippocampus in the brain.
Source: Popular Science China