Alcohol (ethyl alcohol or ethanol), one of the worlds oldest, most widely used, drugs, has many effects on the body, some positive, but most negative. Historically, alcohol has been blamed for many of the worlds tragedies and problems, from the fall of the Roman Empire (What's Your Poison; 1997) (1) to the disbanding of many families. Ironically, it is made from relatively innocuous substances. Fermented grain, fruit juice and honey have been used to make alcohol for thousands of years. Alcohol's use spans nationalities and demographics as it serves to relax and provide a source of enjoyment. It has even been shown to have some salutary effects, such as a blood thinning action beneficial to the cardiovascular system, in addition to the aforementioned social and relaxation aspects.
However, the doses required in these instances are very minimal (1-2 glasses in most cases), and anything beyond this more than outweighs any potential benefits. This is partly because alcohol is classed as a central nervous system depressant, causing the brain to relax and inhibitions to decrease. Ones rational thought, emotional status, judgement, speech and muscle coordination are adversely affected through alcohol consumption. In extreme cases it can cause coma and death. Alcohol is specifically detrimental to bodybuilders, or any athlete, in that it can interfere with recovery, protein synthesis, hydration, motivation , and nutrient intake. Its financial cost is a burden for anyone who buys it.
A review of the research will show that alcohol is poisonous to every organ in the body and will adversely affect everyone who engages in its use to some Extent (1, 6, 7, 8). This article is not intended to dissuade people from using alcohol moderately, for recreational purposes, but will point out, from an athlete and a researchers point of view, its significant shortcomings. Cheers.
Alcohol's Effects Ethyl alcohol is a very small molecule which is soluble in lipid and water solutions. It is metabolized primarily by the liver, where an enzyme called alcohol dehydrogenase breaks the alcohol down into acetaldehyde, which is further broken down into acetate. Acetate is metabolized into carbon dioxide and water, which is excreted. Alcohol is absorbed rapidly from the small intestine (80%) and stomach (20%), before any other nutrients are digested. These properties ensure that alcohol gets into the blood stream and crosses the blood-brain barrier easily. Hence alcohol's instantaneous effect on thought processes. In fact, alcohol has a number of detrimental effects on the brain two of which, central to the scope of this article, will be discussed first. Alcohol, once it has crossed the blood-brain barrier, will inebriate the cerebral cortex (the part of the brain responsible for executive functions such as rational thought) and work its way down to the limbic system. It won't however affect the limbic system. This turns out to be a problem because the limbic system, being the most primitive part of the brain, then takes over the role of rational thought. This is problematic because the limbic system is entirely emotional, and one then begins to think with their emotions rather than the rational area of their brain (the cerebral cortex). A surprisingly small amount of alcohol will have an instant effect on ones ability to control their emotions, and their judgement as a result. A comparatively large amount of alcohol and one might become violent or completely out of control in other respects. As mentioned, alcohol is also a depressant. It depressant effect results from increased transmission of the GABA systems (2). In other words, alcohol consumption creates a demand for more GABA. GABA is a neurotransmitter responsible for restricting, or depressing the excitability of our brain. Glutamate is the Neurotransmitter that has the opposite effect as it is responsible for brain excitability and can be increased through the intake of various stimulants. It now gets a bit complex. The post synaptic receptors (the receptors of one brain cell that receive a message from another brain cell) for GABA, GABA-A, then become stimulated and respond by hyperpolarising the cell membrane and reducing the chance of an action potential occurring. An action potential is an electrical charge propagated through a neuron which causes that neuron to become stimulated. It gets worse. Over time, if a sufficient amount of alcohol is consumed, the GABA receptors become accustomed to a certain amount of alcohol and more is required to get the same depressing and intoxicating effect. In short, tolerance occurs. With more and more alcohol the potential for the GABA receptor to function improperly increases. This may result in hyperexcitability causing, anxiety, tremors, disorientation, and hallucinations when one is not drinking. This is alcohol at its destructive extreme.
In addition to alcohols destructive effects at the time of ingestion, it can also cause neural tissue death when its consumption is stopped. As explained, GABA (a inhibitory neurotransmitter) binds to its GABA-A receptor following alcohol intake. When this happens, a chloride channel is opened and extracellular chloride moves into a intracellular compartment on the receptor. The neuron is hyperpolarized as a result and excitatory postsynaptic potentials (EPSPs) cannot occur, as mentioned. The main point here is that alcohol facilitates the ability of GABA to open chloride channels. With greater (chronic) use of alcohol the neuron may become entirely dependant on alcohol for its GABA function in the long term. However, at the time of chlorides uptake another process, this time involving the glutamine (excitatory neurotransmitter) receptors, causes further problems. The glutamate system is up-regulated with alcohol withdrawal and calcium-channel activity is stimulated. Calcium is released directly onto the post synaptic neuron (calcium influx) in large amounts and neural death occurs. This happens particularly after binge sessions that occur on a regular basis.
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