Table of ContentsView AllTable of ContentsHow Fast Is Alcohol Metabolized?How the Body Metabolizes AlcoholThe Dangers of AcetaldehydeAcetaldehyde and ImpairmentGenetics and MetabolismGenetics and AlcoholismIt’s Not All GeneticHealth ConsequencesMetabolism-Based Treatment

Table of ContentsView All

View All

Table of Contents

How Fast Is Alcohol Metabolized?

How the Body Metabolizes Alcohol

The Dangers of Acetaldehyde

Acetaldehyde and Impairment

Genetics and Metabolism

Genetics and Alcoholism

It’s Not All Genetic

Health Consequences

Metabolism-Based Treatment

Heavy drinking increases the risk of a variety of negative health consequences from liver disease to cancer. But some people who drink heavily appear to be at a greater risk for developing these problems than others.

Researchers believe the difference between those with greater risk and those with lower risk may involve how the body metabolizes, or breaks down and eliminates alcohol, which can vary widely from individual to individual.

At a GlanceDrinking comes with many risks, some of which stem from how we metabolize alcohol. Individual differences can affect how quickly we break it down, as well as the effects it can have on our bodies. Some people have specific genes that lead to unpleasant side effect after drinking even a small amount. This can protect against alcohol use problems, but it can also heighten the health risks when people do drink.

At a Glance

Drinking comes with many risks, some of which stem from how we metabolize alcohol. Individual differences can affect how quickly we break it down, as well as the effects it can have on our bodies. Some people have specific genes that lead to unpleasant side effect after drinking even a small amount. This can protect against alcohol use problems, but it can also heighten the health risks when people do drink.

No matter how much alcohol you consume, your body can only metabolize a certain amount every hour. Alcohol is metabolized at a rate of approximately one drink per hour.When more than this is consumed, it builds up in the body and causes intoxication.

So if you consume a single drink, you may return to a blood alcohol concentration (BAC) of 0.00 in an hour or two. If you consume a larger amount of alcohol in a short period of time, it will take much longer for your liver to metabolize it.

The results illustrate the fact that the body can only break down and eliminate so much alcohol per hour. It is important to remember that these times are averages.

In reality, the time each individual takes to metabolize alcohol can vary widely. But in all cases, alcohol is metabolized more slowly than it is absorbed.

When alcohol is consumed, it is absorbed into the blood from the stomach and intestines. Then enzymes, bodily chemicals that break down other chemicals, begin to metabolize the alcohol.

Although acetaldehyde is present in the body a short period of time, it is highly toxic and a known carcinogen.

Lastly, a small quantity of alcohol is not metabolized and is instead eliminated in the breath and urine, which is howBACis measured in breath and urine tests.

Small amounts of alcohol are metabolized in the gastrointestinal tract, which acetaldehyde can also damage.Some researchers believe the effects of acetaldehyde go beyond the damage it can cause to tissues but might also be responsible for some of thebehavioral and physiological effectsattributed to alcohol.

Animal studies have found that acetaldehyde in the brain contributes to alcohol’s behavioral effects.Such effects can include loss of judgment, decreased concentration, and impaired coordination.

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When researchers administered acetaldehyde to laboratory animals, it caused incoordination, memory impairment, and sleepiness.Conventional thinking suggests that acetaldehyde alone can’t cause these effects because the brain protects itself from toxic chemicals in the blood with its unique blood-brain barrier.

Nevertheless, when the enzymes catalase and CYP2E1 metabolize alcohol—which only happens whenlarge amounts are consumed—acetaldehyde can be produced in the brain itself.

Acetate, one of the products of the breakdown of acetaldehyde, can cross the blood-brain barrier where it impacts GABA, an inhibitory transmitter. This inhibitory effect can then lead to impaired motor function.

The size of the liver and body mass of the drinker are factors in how much alcohol a person can metabolize in an hour, but research tells us that the genetic makeup of the individual is probably the most significant factor in how efficiently alcohol is broken down and eliminated.

Variations of ADH and ALDH enzymes have been traced to variations in the genes that produce these enzymes. Some people have ADH and ALDH enzymes that work less efficiently than others, while others have enzymes that work more effectively.

Simply put, this means some people have enzymes that can break down alcohol to acetaldehyde or acetaldehyde to acetate, more quickly than others.

If someone has a fast-acting ADH enzyme or a slow-acting ALDH enzyme, they can have toxic acetaldehyde build up in the body, creating dangerous or unpleasant effects when they drink alcohol.

The Difference Between Women and Men

Women absorb and metabolize alcohol differently from men. Research has shown that women may have less ADH enzyme activity in the stomach, allowing a larger percentage of alcohol to reach the blood before being metabolized.

This could be one reason women who drink are more susceptible to alcohol liver disease, heart muscle damage, and brain damage than men.

Women and the Effects of Alcohol

Genetics can also be a factor in whether or not the person is susceptible to developing alcohol use disorders.

For example, there is one variation of these enzymes that causes a build-up of acetaldehyde to the point it causes facial flushing, nausea, and a rapid heart rate. These effects can occur with even moderate alcohol consumption.

This gene variant is common in people of Chinese, Japanese, and Korean descent, who may drink less because of the unpleasant side effects. Around 36% to 45% of people of East Asian descent experience this effect when they consume small amounts of alcohol.

Their gene variant has a protective effect againstdeveloping alcoholism. That protective gene, ADH1B2, is rarely found in people of European and African descent. Another variant, ADH1B3, is found in around 25% of Black people and protects against alcoholism.

That said, some research indicates that variations of the ALDH enzyme, ALDH1A12, and ALDH1A13 may be associated with alcoholism in Black individuals.

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According to the National Institute on Alcohol Abuse and Alcoholism (NIAAA), about half the risk of developing an alcohol use disorder stems from genetics. That means our genes play an important part, but other factors also make up half of the story.

Children of people with alcohol use disorder are more likely than the general population to develop problems with alcohol use. This increased risk may, in part, be a result of some shared genetic factors, but experts also believe that shared environmental and social factors likely are at play as well.

For example, research has found that alcohol use disorders increased in people of Japanese descent from 2.5% to 13% between 1979 and 1992 among those who carried the protective ADH1B*2 gene. This suggests that other factors can overcome protective genetic effects.

In the United States, more Native Americans die of alcohol-related causes than any other ethnic group. However, researchers found there is no difference in the enzyme patterns or alcohol metabolism rates of Native Americans and Caucasians, indicating that there are other factors at play in the development ofalcohol-related problems.

Alcohol’s Health Consequences

Heavy orchronic alcohol consumptionhas been linked to a long list of negative health consequences and long-term adverse effects. Some of these health problems have been directly linked to how alcohol is metabolized in the body and the production of acetaldehyde.

Cancer

The toxic effects of acetaldehyde have been linked to the development of cancers of the mouth, throat, upper respiratory tract, liver, colon, and breasts.

Ironically, the genes that “protect” some individuals from developing alcoholism may actually increase their vulnerability to developing cancer.

Although they are less likely to drink large amounts of alcohol, these people are at greater risk for developing cancer because their bodies produce more acetaldehyde when they do drink. So, even some moderate drinkers are a greater risk of developing cancer.

Because the liver is the organ that metabolizes most of the alcohol in the body, it is where most of the acetaldehyde is produced, it is particularly vulnerable to the effects of alcohol metabolism. More than 90% of heavy drinkers develop fatty liver.

Understanding Alcoholism and the Signs of Severe Drinking Problems

Because some alcohol metabolism also takes place in the pancreas, it is exposed to high levels of acetaldehyde and FAEEs. However, around 10% to 15% of heavy drinkers develop alcoholic pancreatitis, indicating that alcohol consumption alone is not the only factor in developing the disease.

Other factors may include smoking, diet, drinking patterns and the differences in how alcohol is metabolized may play a role, but none have been definitively linked to pancreatitis.

Increased Body Weight

Alcohol consumption does not necessarily lead to increased body weight, in spite of its relatively high caloric value. Although moderate alcohol consumption does not lead to weight gain in lean men or women, studies have found that alcohol added to the diets of overweight people does lead to weight gain.

Effects on Sex Hormones

In men, alcohol metabolism contributes to testicular injury and impairs testosterone synthesis and sperm production.Prolonged testosterone deficiency may contribute to feminization in males, such as breast enlargement.

In women, alcohol metabolism may cause increased production of estradiol and decreased estradiol metabolism, resulting in increased levels. Estradiol contributes to increased bone density and a reduced risk of coronary artery disease.

Interactions With Medication

Alcohol consumption affects the metabolism of many different medications, increasing the activity of some and diminishing the effectiveness of others.

Chronic heavy drinking has been found to activate the CYP2E1 enzyme, which can change acetaminophen into a toxic chemical that can cause liver damage even when taken in regular therapeutic doses.

Can You Drink Alcohol While You’re on a Medication?

National Institute on Alcohol Abuse and Alcoholism-funded research continues to examine how variations in the way the body metabolizes alcohol may influence why some people drink more than others and why some develop serious alcohol-related health problems.

Researchers believe how the body breaks down and eliminates alcohol may hold the key to explaining the differences, and continued research may help in developing metabolism-based treatments for people who drink and are at risk for developing alcohol-related health problems.

Current evidence-based treatments for alcohol use disorder include:

Treatments vary depending on the needs of the individual. A combination of therapy, medications, and 12-step facilitation can be the most effective in many cases.

24 Sources

Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

California Department of Alcoholic Beverage Control.Alcohol facts.

National Institute on Alcohol Abuse and Alcoholism.Alcohol metabolism.

National Cancer Institute.Alcohol and cancer risk.

Rodriguez FD, Coveñas R.Biochemical mechanisms associating alcohol use disorders with cancers.Cancers (Basel). 2021;13(14):3548. doi:10.3390/cancers13143548

Hyun J, Han J, Lee C, Yoon M, Jung Y.Pathophysiological aspects of alcohol metabolism in the liver.IJMS. 2021;22(11):5717. doi:10.3390/ijms22115717

Ramchandani VA.Genetics of alcohol metabolism. In: Watson RR, Preedy VR, Zibadi S, eds.Alcohol, Nutrition, and Health Consequences. Humana Press; 2013:15-25. doi:10.1007/978-1-62703-047-2_2

Jiang Y, Zhang T, Kusumanchi P, Han S, Yang Z, Liangpunsakul S.Alcohol metabolizing enzymes, microsomal ethanol oxidizing system, cytochrome p450 2e1, catalase, and aldehyde dehydrogenase in alcohol-associated liver disease.Biomedicines. 2020;8(3):50. doi:10.3390/biomedicines8030050

Harvard Health Publishing.Ask the doctor: Why does alcohol affect women differently?

Centers for Disease Control and Prevention.Excessive alcohol use is a risk to women’s health.

Jeon S, Kang H, Cho I, Cho S il.The alcohol flushing response is associated with the risk of depression.Sci Rep. 2022;12(1):12569. doi:10.1038/s41598-022-16276-2

McCarthy DM, Pedersen SL, Lobos EA, Todd RD, Wall TL.ADH1B*3 and response to alcohol in African-Americans.Alcohol Clin Exp Res. 2010;34(7):1274-1281. doi:10.1111/j.1530-0277.2010.01205.x

National Institute on Alcohol Abuse and Alcoholism.Genetics of alcohol use disorder.

Wang W, Wang C, Xu H, Gao Y.Aldehyde dehydrogenase, liver disease and cancer.Int J Biol Sci. 2020;16(6):921-934. doi:10.7150/ijbs.42300

Ehlers CL, Gizer IR.Evidence for a genetic component for substance dependence in Native Americans.AJP. 2013;170(2):154-164. doi:10.1176/appi.ajp.2012.12010113

Zhang J, Zhang S, Song Y, et al.Facial flushing after alcohol consumption and the risk of cancer: A meta-analysis.Medicine (Baltimore). 2017;96(13):e6506. doi:10.1097/MD.0000000000006506

Osna NA, Donohue TM Jr, Kharbanda KK.Alcoholic liver disease: Pathogenesis and current management.Alcohol Res. 2017;38(2):147-161.

Herreros-Villanueva M, Hijona E, Bañales JM, Cosme A, Bujanda L.Alcohol consumption on pancreatic diseases.World J Gastroenterol. 2013;19(5):638-647. doi:10.3748/wjg.v19.i5.638

Traversy G, Chaput JP.Alcohol Consumption and Obesity: An Update.Curr Obes Rep. 2015;4(1):122-130. doi:10.1007/s13679-014-0129-4

Erol A, Ho AM, Winham SJ, Karpyak VM.Sex hormones in alcohol consumption: a systematic review of evidence.Addict Biol. 2019;24(2):157-169. doi:10.1111/adb.12589

Bianco A, Thomas E, Pomara F, et al.Alcohol consumption and hormonal alterations related to muscle hypertrophy: A review.Nutr Metab (Lond). 2014;11(1):26. doi:10.1186/1743-7075-11-26

Kumar S, Singla B, Singh AK, Thomas-Gooch SM, Zhi K, Singh UP.Hepatic, extrahepatic and extracellular vesicle cytochrome P450 2E1 in alcohol and acetaminophen-mediated adverse interactions and potential treatment options.Cells. 2022;11(17):2620. doi:10.3390/cells11172620

National Institute on Alcohol Abuse and Alcoholism.Recommended evidence-based treatment: Know the options.

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