Alcohol use is pervasive in today’s culture. Even though many people drink frequently, very few people really know the specifics of what alcohol does to the brain and body. These effects of alcohol are far-reaching and can sometimes be very dangerous. In this article, we will take a look at the exact way that alcohol affects the brain and the various systems of the body.
How Alcohol Affects The Brain
The most direct and immediate impact of alcohol is on the neurotransmitters GABA and glutamate. Both GABA and glutamate are used to calm (GABA) and intensify (glutamate) neurological signals in the brain. Alcohol directly causes an increase in GABA and a sharp drop in glutamate which produces the depressant effects. Dopamine and serotonin are also affected but in a more indirect way. Alcohol’s impact on these neurotransmitters is responsible for mood elevation and anxiety reduction (serotonin) and the pleasure and good memories associated with alcohol use (dopamine).
Changes in the levels of these neurotransmitters can produce a variety of psychological and neurological effects, including:
After taking a drink, the levels of GABA rise while glutamate levels decrease and someone will begin to feel relaxed and will be less aware of their environment. This also leads to impaired coordination, reduced motor control, and a slower reaction time which will make someone more clumsy the more they drink. This also impairs judgment and higher reasoning, which can be attributed to the anti-anxiety effect of increased GABA levels making someone feel like things are less important or less risky than they actually are. Alcohol also impairs memory. The impairment can be mild at low doses but when a person drinks more, their memory becomes more and more impaired, eventually resulting in a blackout. A blackout is when the brain is so impaired that it does not create and store memories effectively. Vision is impaired as well, as alcohol can impair the muscles that focus and control the eyes as well as interfering with the signals from the optic nerve.
The emotional effects of alcohol use are complicated and paradoxical. In the short term, alcohol can make someone feel happy, calm, and have more fun doing normal, mundane things. In the long term the effects are the opposite. When someone comes down from alcohol, typically the next morning, a hangover is often the result. This is not only the physical symptoms including headache and stomach trouble but an increase in anxiety and mild feelings of depression. Now with decreased GABA and increased glutamate, someone will begin to feel on-edge and tense. This will only worsen the longer alcohol is used since the brain’s regulation processes will make this more pronounced over time.
Someone who is drinking is likely to feel more outgoing and friendly since their inhibitions are down. They don’t have the normal hesitance to be completely open with those around them, and this can promote feelings of solidarity and fellowship. Additionally, the effect that alcohol has on dopamine means that positive memories are strongly linked to alcohol use. This can contribute to a deepening dependence on alcohol, but first and foremost it means that someone associates alcohol with good times and this produces a desire to drink to recapture those times. This is one of the most subtle, but dangerous effects that chronic alcohol use produces.
Alcohol decreases someone’s ability to perform “big picture” thinking. This means that short-term fun will take priority over long-term risk. This may include driving drunk, fighting, stealing, and anonymous sex. Thrills and excitement seem much more attractive since the potential risks can’t be weighed properly. Coupled with the risks of lowered reasoning, sex drive is also increased through alcohol use. With greater sexual impulses, someone who is drunk is much more likely to give in to base instincts since they lack the ability to properly think through the implications. This can result in unsafe sex, sex they would later regret, and sex with people that the drinker would not sleep with if they were sober.
Due to the effects of alcohol, people tend to be much more boisterous and rowdy when they are drunk. This can, in turn, increase risks of all sorts since there is a large increase in risk-taking behavior in general among active drinkers. This could be in the form of mildly risky activities, but can also include someone doing drugs they normally would not do. Mixing drugs with alcohol can be extremely dangerous, and depending on the drug, combining alcohol and certain drugs could easily be fatal.
How Alcohol Affects The Body
Alcohol has a very heavy impact on the body as well as the brain. The physical effects of alcohol are mostly depressive but it can also affect other systems, interrupting normal function. The symptoms vary depending on the system affected, so we have broken down these effects as follows:
While alcohol is a central nervous system depressant, it has the opposite effect when it comes to the heart. Alcohol acts as a vasodilator, causing the blood vessels to relax. This lets more blood reach the tissues and skin and is responsible for the flushing of the face when drinking. This also lowers blood pressure, meaning that the heart has to work harder to circulate blood resulting in a higher heart rate. This can lead to an increased risk of stroke, as blood pressure fluctuations happen more frequently. Oxidative stress is also a factor in the cardiovascular system as alcohol metabolism and the toxic byproducts it produces must travel through the blood to be filtered. These byproducts can cause damage to blood vessels, as well as potentially damage other organs as the blood passes through them. This is known to play a role in damage to the myocardium (heart muscle tissue). Finally, alcohol makes it more difficult for blood to clot which increases the risk of blood loss through injury. 1
When drinking alcohol, a person’s breathing rate usually increases. This is because the body needs more oxygen due to a higher heart rate. Alcohol use also changes the structure of the lungs making them more susceptible to infection and injury. When drinking alcohol, the interior surface of the lungs (specifically the alveolar epithelium) becomes more permeable. This will encourage fluids to leak from cells into the airways which can cause a wide range of issues, the most serious of which is pulmonary edema. Aside from compromising lung immune function, this reduces the overall efficiency of the lungs and will worsen any other lung issues that may be present. 2, 3
While the majority of alcohol metabolism occurs in the liver, it can occur elsewhere in the body as well. Alcohol metabolism is the process by which the body rids itself of alcohol, which is technically a toxin. This first requires alcohol to be metabolized into acetaldehyde, which is extremely toxic and a known carcinogen in humans. Alcohol use takes a heavy toll on the gastrointestinal tract. This can begin in the stomach, where alcohol is corrosive to the protective mucus of the stomach and increases the risk of a stomach ulcer or esophageal issues. Once in the small intestine, alcohol really begins to do more major damage as it can kill many of the healthy gut bacteria which help us digest food. The most immediate effect alcohol has in the digestive system is to prohibit the normal absorption of nutrients such as fats, proteins, and vitamins and it can also damage mucous membranes, which are prevalent in the gut.
Additionally, since alcohol is a toxin the body will prioritize alcohol metabolism over normal food metabolism. This can result in brain damage through alcohol-induced thiamine deficiency, as well as chronic diarrhea and poor nutrition in general. This means that even though a person may eat while they are drinking, they are getting much less nutrition from this food while alcohol is present. 4
Alcohol can have a serious impact on reproduction and fertility in both men and women, and drinking alcohol while pregnant can lead to a wide range of very serious complications and birth defects. Some of the specific reproductive effects may include:
- Male Reproduction: Alcohol has a negative impact on the quality of sperm. High levels of alcohol use (binge or heavy drinking) are directly correlated to sperm count, sperm motility (ability to swim), and physical sperm defects. 5, 6
- Female Reproduction: Alcohol has a powerful impact on the female reproductive system. This can vary depending on age and sexual maturity, but alcohol use during puberty is known to disrupt many sex hormones like estrogen and may delay the onset of puberty. Post-puberty alcohol use can also disrupt the normal reproductive cycles resulting in many issues such as menstrual irregularities, ovarian failure or anovulation, and infertility to name just a few. The effects of alcohol on postmenopausal women are not well defined, but alcohol is known to increase the risk of osteoporosis. It is unclear if this is caused directly or indirectly by the nutritional deficits resulting from alcohol-induced GI disruption. 7, 8
- During Pregnancy: Alcohol is a known cause of a large number of birth defects, collectively known as fetal alcohol spectrum disorders. The most serious FASD disorder is fetal alcohol syndrome which causes mental disabilities and physical deformities. Alcohol use before and during pregnancy can also increase the risk of the newborn dying from sudden infant death syndrome. While the amounts of alcohol used can increase these risks, it is becoming clear that there is no safe level of alcohol use during pregnancy. 9, 10, 11
- Alcohol Research – Current Reviews: Alcohol’s Effects on the Cardiovascular System
- Alcohol Research – Current Reviews: Alcohol and the Lung
- Alcohol Research – Current Reviews: Alcohol’s Effects on Lung Health and Immunity
- Alcohol Health and Research World: Alcohol’s Role in Gastrointestinal Tract Disorders
- Human Reproduction: Alcohol and Male Reproductive Health – A Cross-Sectional Study of 8344 Healthy Men from Europe and the USA
- Andrology: Male Caffeine and Alcohol Intake in Relation to Semen Parameters and In Vitro Fertilization Outcomes Among Fertility Patients
- National Institute on Alcohol Abuse and Alcoholism: Alcohol’s Effect on Female Reproductive Function
- Fertility and Sterility: Effects of Alcohol Consumption on Female Fertility During an 18-year Period
- Primary Care Companion to the Journal of Clinical Psychiatry: Alcohol Use During Pregnancy – Prevalence and Impact
- Trends in Cognitive Sciences: Drinking During Pregnancy and the Developing Brain – Is Any Amount Safe?
- Centers for Disease Control: Excessive Alcohol Use is a Risk to Women’s Health