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Home >> How Alcohol Affects Your Health
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The Many people enjoy drinking as part of socializing, to celebrate important occasions, or with a meal. But alcohol can also be misused. It is important to understand how it affects the body. Knowing your limits can help you avoid harm.
How much you drink determines the effect of alcohol will have on you. But who you are and how you drink also matter.
This section outlines how your body processes alcohol and how it affects health. The most important things to remember is that each person is different.
If you have any questions or concerns about your own relationship with alcohol, it is always best to consult a health professional to help you assess how it may affect you.
As soon as begin to drink, some alcohol moves into your bloodstream and circulates throughout your body. [i][ii]
Most of it will eventually reach your liver where it is broken down with the help of specialized proteins called enzymes into a substance called acetaldehyde. [iii]
Because acetaldehyde is toxic, the body quickly breaks it down further into carbon dioxide and water so that it is easily eliminated along with other bodily waste.
If you drink too much or too quickly, your liver cannot keep up and acetaldehyde will build up and cause harm.
Some people have a genetic trait that prevents the effective breakdown of acetaldehyde. They have a negative reaction to drinking alcohol that can include facial flushing, nausea, and headaches. They are also at higher risk of some longer-term health problems.[iv]
[ii] Paton, A. Alcohol in the body. BMJ, 2005. 330: 85-7.
[iii] National Institute on Alcohol Abuse and Alcoholism (NIAAA). Alcohol flush reaction: does drinking alcohol make your face red? Bethesda, MD: NIAAA, 2022.
[iv] National Institute on Alcohol Abuse and Alcoholism (NIAAA). Alcohol’s effects on health. Bethesda, MD: NIAAA, 2022.
Some people of Chinese, Japanese, and Korean origin experience an unpleasant ‘flushing’ reaction when they drink, which makes their faces turn red.
They are likely have a genetic trait that prevents the liver from breaking down acetaldehyde efficiently.
If you have this genetic trait, your health risk may be higher than it is for other people. Getting medical advice is a good idea.
How alcohol is metabolized in the body
In most countries there is a legal limit for how much alcohol you can drink when you drive a car, based on the effect alcohol has on your coordination, reaction time, judgment, and ability to concentrate. [i][ii]
The level of alcohol in your blood, or blood alcohol content (BAC), reflects how many drinks you have had. For a normal adult, drinking roughly 1 one standard drink in 1 hour increases BAC by approximately 0.02%.
This is just an approximation, and you should never use this conversion to determine whether you are fit to drive – drinking and driving do not mix.
BAC limits for the purposes of driving a car and operating other motorized vehicles vary.[iii] You should be aware of the legal BAC limits that apply in your country.
[i] Irwin, C. et al. Effects of acute alcohol consumption on measures of simulated driving: A systematic review and meta-analysis. Accid Anal Prev, 2017. 102: 248-266.
[ii] Martin, T.L. et al. A review of alcohol-impaired driving: the role of blood alcohol concentration and complexity of the driving task. J Forensic Sci, 2013. 58:1238-1250.
[iii]World Health Organization (WHO). Global Status Report on Road Safety 2023. Geneva: WHO, 2023.
In Singapore, the permitted BAC level for driving a motor vehicle is 0.08%.
Your blood alcohol content (BAC) reflects the percentage of alcohol in your blood. A BAC level of 0.02, for example, means that the 0.02% of your blood volume is alcohol.
Because some alcohol is exhaled from your lungs before it enters the rest of your body, breath alcohol is used as a quick and efficient indicator of BAC and helps in road traffic law enforcement. Different countries set different BAC limits.
Your BAC after drinking depends on many factors.
Your BAC depends not only on how much alcohol you drink, but also on:
If you are drinking alcohol, no matter how much you drink, the best choice is to not drive, whether it is a car, a motorbike or other motorized two-wheeler, or even if you are riding a bicycle.
Alcohol reaches the brain quickly and affects your behavior first. Depending on how much you drink, you may feel sleepy, animated, or intoxicated. But alcohol also affects your long-term physical and mental health.
How drinking affects your health depends on how much you drink, but also on how you drink and on who you are. Recommendations and guidelines are available to help you make informed choices.
As you drink, you may at first feel relaxed, but as you drink more, it will affect your behavior, coordination, and reaction time.
Drinking too much can affect your judgment and you may make poor decisions about what you do, how you interact with other people, and your safety. Drinking more increases the risk that you or others may be hurt or even killed.
Drinking affects your health over time. Without exception, drinking excessively is hazardous to your physical and mental health. The relationship with moderate drinking is more complex, and for most healthy adults, it can be compatible with a balanced and healthful lifestyle. [i]
The more alcohol you drink, the higher your risk of developing various diseases, including:
Cardiovascular disease (CVD). Risk of high blood pressure, heart disease, and stroke increases the more you drink. [ii] At the same time, scientific studies show that moderate drinking may reduce the risk of CVD in some people. [iii][iv]
Cancer risk. Risk of several cancers (mouth, throat, breast, colorectum, and liver) has been linked with heavy drinking.[v] For women, even moderate drinking may increase risk breast cancer. [vi][vii]
Liver disease and digestive health. Drinking heavily over many years may lead to liver cirrhosis and liver cancer and raise your risk of pancreatitis and gall bladder disease. [viii]
Diabetes. Heavy drinking can increase your risk of developing adult-onset (Type 2) diabetes, but scientific studies show that drinking moderately, along with leading a healthy lifestyle, can lower your risk.[ix][x]
Memory and cognitive function. Drinking heavily can result in dementia and cognitive decline. Moderate drinking by older has been linked with improved memory and cognitive function.[xi]
Fetal alcohol effects. Drinking in pregnancy increases the risk that a child will be born with serious cognitive and physical problems, including Fetal Alcohol Syndrome (FAS). Women who are pregnant should not drink alcohol.[xii]
Alcohol Use Disorder (AUD). People who drink very heavily over many years may develop AUD or become ‘dependent’ on alcohol. Alcohol use disorder (AUD) is a psychiatric condition that needs careful monitoring and treatment through therapy or medication.[xiii]
[i] Hendriks HFJ. Alcohol and human health: what is the evidence? Annu Rev Food Sci Technol. 2020, 11:1-21.
[ii] Briasoulis, A. et al. Alcohol consumption and the risk of hypertension in men and women: a systematic review and meta-analysis. J Clin Hypertens (Greenwich). 2012. 14(11): 792-8.
[iii] Yoon, S.J. et al. The protective effect of alcohol consumption on the incidence of cardiovascular diseases: is it real? A systematic review and meta-analysis of studies conducted in community settings. BMC Public Health. 2020. 20(1): 90;
[iv] Ronksley, P.E. et al. Association of alcohol consumption with selected cardiovascular disease outcomes: a systematic review and meta-analysis. BMJ. 2011. 342: d671.
[v] Cao, Y. & Giovannucci, E.L. Alcohol as arisk factor for cancer. Semin Oncol Nurs. 2016. 32(3):325-31.
[vi] Bagnardi, V. et al. Alcohol consumption and site-specific cancer risk: a comprehensive dose-response meta-analysis. Br J Cancer. 2015. 112(3): 580-93.
[vii] Choi, Y.J. et al. Light alcohol drinking and risk of cancer: a meta-analysis of cohort studies. Cancer Res Treat. 2018. 50(2):474-487.
[viii]Zhang, R. et al. Risk factors and protective factors for alcohol-related liver disease: a systematic review and meta-analysis. Alcohol Clin Exp Res. 2022. 46(12): 2128-2136.
[ix] Li, X.H. et al. Association between alcohol consumption and the risk of incident type 2 diabetes: a systematic review and dose-response meta-analysis. Am J Clin Nutr. 2016. 103(3): 818-29.
[x] Llamosas-Falcón, L. et al. The relationship between alcohol consumption, BMI, and Type 2 diabetes: a systematic review and dose-response meta-analysis. Diabetes Care. 2023.46(11): 2076-2083.
[xi] Rehm, J. et al. Alcohol use and dementia: a systematic scoping review. Alzheimers Res Ther. 2019. 11:1.
[xii] Popova, S. et al. Fetal alcohol spectrum disorders. Nat Rev Dis Primers. 2023. 9(1):11.
[xiii] American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR). 2023. Washington, DC: APA.
Nobody should drink alcohol to improve their health and people who do not drink should not start for health reasons. Drinking can also make some diseases worse.
If you have any questions about how drinking may affect your health, it is best to seek advice from a health professional to help determine what is best for you.
How alcohol affects your health depends very much on who you are and on your lifestyle. Understanding these factors can help you moderate your drinking or choose not to drink alcohol to manage and reduce your health risk.[i]
Everybody has a different relationship with alcohol and has different factors that can increase or decrease risk of harm.
How alcohol will affect you over the long term depends on:
Most diseases that involve alcohol as a risk factor also occur in people who do not drink at all.
[i] World Cancer Research Fund / American Institute for Cancer Research. (2018). Diet, nutrition, physical activity and cancer: A global perspective (Continuous update project expert report 2018).
[ii] Erol, A. & Karpyak, V.M. Sex and gender-related differences in alcohol use and its consequences: Contemporary knowledge and future research considerations. Drug Alcohol Depend, 2015. 156: 1-13.
[iii] Maddern, X.J. et al. Sex differences in alcohol use: is it all about hormones? Endocrinology, 2024. 165(9):bqae088.
[iv]Lees, B. et al. Effect of alcohol use on the adolescent brain and behavior. Pharmacol Biochem Behav. 2020, 192:172906.
[v] Xu, Q. et al. The risk of falls among the aging population: A systematic review and meta-analysis. Front Public Health, 2022. 10:902599.
[vi] Fenollal-Maldonado, G. et al. Alcohol Use Disorder in older adults. Clin Geriatr Med, 2022. 38(1):1-22.
[vii] Kaminsky, L.A. et al. The importance of healthy lifestyle behaviors in the prevention of cardiovascular disease. Prog Cardiovasc Dis, 2022. 70:8-15.
[viii] English, L.K. et al. Evaluation of dietary patterns and all-cause mortality: a systematic review. JAMA Netw Open, 2021. 4(8):e2122277.
[ix] Akerlind, I. & Hörnquist, J.O. Loneliness and alcohol abuse: a review of evidence of an interplay. Soc Sci Med, 1992. 34: 405-414.
[x] Lees, B. et al. Effect of alcohol use on the adolescent brain and behavior. Pharmacol Biochem Behav, 2020. 192:172906.
[xi] Cservenka, A. & Azma, S. Neural correlates associated with a family history of alcohol use disorder: A narrative review of recent findings. Alcohol Clin Exp Res (Hoboken). 2024, Epub ahead of print.
[xii]Zhou, H. & Gelernter J. Human genetics and epigenetics of alcohol use disorder. J Clin Invest. 2024, 134(16):e172885.
[xiii]Edenberg, H.J. The genetics of alcohol metabolism: role of alcohol dehydrogenase and aldehyde dehydrogenase variants. Alcohol Res Health. 2007;30(1):5-13.
Any amount of alcohol may increase health risks in some people and requires special recommendations about drinking.
For example, advice to pregnant women is to avoid drinking any alcohol to avoid harm to their fetus. Some countries have formal guidelines for pregnancy and breastfeeding and others warn both men and women trying to conceive to avoid drinking alcohol because it may affect fertility.
Young people are more likely than adults to experience harm from drinking and are advised not to drink alcohol until they have reached a legal age at which purchasing and drinking alcohol is permitted. Age limits are mandated by governments and vary from country to country. [xiv] For practical purposes, the legal purchase age is generally taken as the drinking age, even though some countries mandate limits for both.
In Singapore the legal age limit is 18 years, making it illegal to sell alcohol to anyone who is younger.
[xiv] International Alliance for Responsible Drinking (IARD). Minimum legal age limits. Washington, DC: IARD, 2022.
How you drink also matters in terms of the impact on health.
Drinking moderately can be enjoyable and enhance many social experiences. But if you consume excessive amounts of alcohol in a short time, or ‘binge’ drink, you will quickly become intoxicated and increase your risk of injuring yourself or others, and of poisoning, coma, or even death.
If you choose to drink, always choose moderation and avoid any activity that can place you or other people in danger.
Have you wondered what your risk from drinking means?
Usually, it is presented as a comparison between risk to a person who drinks and someone who doesn’t.
This is known as relative risk.
Sometimes these numbers can seem terrifying, but your risk also depends on how common a disease is.
This is known as absolute risk.
Let’s consider the risk of a hypothetical disease “chronitis”.
Absolute risk:
Relative risk:
This example uses a made-up disease but how you calculate risk is the same for a real one.
Risk from drinking alcohol also depends on other factors that need to be considered in making decisions about alcohol consumption.
The amount of alcohol in a standard drink of beer is the same as in a standard drink of wine or spirits. The alcohol in beer is less concentrated, but beer is served in larger glasses and containers. But a standard drink is always a standard drink in terms of the alcohol it contains.
While moderate drinking can be part of a healthy lifestyle for many healthy adults, drinking alcohol is not a way to improve your health. People who don’t drink should not start drinking, and those who do drink should consider their overall personal and lifestyle risk and also how much they are drinking.
Because alcohol affects young people differently than it does adults and because young people are inexperienced with both drinking and driving, many countries have a lower BAC threshold for driving for young people (as well as for novice and professional drivers).
Flushing when you drink alcohol most likely means that your body is not able to process alcohol very well. Because of this, people with this trait should take care when drinking. The flushing reaction is most often seen in people from China, Japan, and Korea and is less prevalent among other groups.
The resources on this website are not intended as health advice to individuals. People with specific questions about their alcohol consumption are encouraged to consult a healthcare professional. Together, they can determine what is best for that individual, based on individual risk factors, including family history, genetics, and lifestyle. For some people, the better choice may be to not drink at all.
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