What does drinking alcohol do to your body?

It’s natural to wonder how the substances we consume affect our bodies. Many Americans choose to drink, so it’s no surprise that alcohol’s impact on the body is of particular interest.

We spoke to physician Maher Karam-Hage, M.D., researcher Carrie Daniel-MacDougall, Ph.D., and senior clinical dietitian Victoria Lee to learn how alcohol impacts the body and the best way to proceed.

Alcohol increases cancer risk

Consuming alcohol in any quantity has been shown to increase the risk of cancers including: 

• oral cancer
• throat cancer
• colorectal cancer
• esophageal cancer
• liver cancer
• breast cancer

In fact, the National Institutes of Health (NIH) writes that an estimated 5.5% of new cancer diagnoses and 5.8% of cancer deaths worldwide are linked to drinking alcohol. 

Karam-Hage says the longer someone has been drinking, the more likely they are to develop cancer. 

Here are a few of the reasons why alcohol increases cancer risk. 

Alcohol is a toxin

No matter what type of alcohol you drink — be it wine, beer, or liquor — it contains ethanol, Lee says. She notes that when your body breaks down ethanol, it produces a carcinogen called acetaldehyde that damages DNA. 

“DNA is a molecule needed by nearly every cell in our body for information on how to properly function, repair and regrow,” Lee says. “If cells cannot properly repair themselves, cancer can grow.” 

Karam-Hage adds that alcohol impacts all of our organs, but particularly the brain, liver, esophagus and stomach. “Alcohol has a toxic effect on many organs,” he says.

Alcohol isn’t nutritious

Alcohol has what Daniel-MacDougall describes as empty calories. “It provides calories, but no other nutrients,” she says.

Consuming more calories than your body needs can lead to weight gain. Excess body weight increases a person’s risk for cancer and other diseases. 

Alcohol changes how the body uses nutrients

When you drink alcohol, your body is less able to absorb and use a variety of nutrients that can protect it from cancer, Lee says. These nutrients – which include Vitamins A, B1, B6, C, D, E and K, folate, iron and selenium – help to keep the body healthy, protect cells, create and repair DNA, and reduce inflammation.

Alcohol can change hormone levels

Alcohol can also affect your hormones. 

“It can increase estrogen levels which might increase risk of breast cancer in some women,” Lee says.

Alcohol alters the gut microbiome

Alcohol can also alter the body’s oral and gut microbiome, which Daniel-MacDougall describes as the balance of bacteria, viruses and fungi that help to keep the body healthy. 

One of the microbiome’s roles is to separate alcohol toxins so the body can remove them. “The gut microbiome is a critical link between the digestive system, the liver and the immune system, playing a big part in how our body metabolizes alcohol and manages that amount of ethanol or toxins that come from alcohol,” she says. 

While Daniel-MacDougall notes a healthy body may be able to break down and remove a limited amount of alcohol, many factors can impact how your body reacts when you drink. On top of that, drinking too much rapidly alters the gut microbiome with short- and long-term consequences.

One of those short-term consequences? That ‘sick to your stomach’ feeling you might experience after overindulging.

“There’s a reason why drinking too much alcohol makes us sick to our stomachs from vomiting to diarrhea," she says. “You’re sort of overwhelming the system.”

Over time, she explains that an unhealthy gut microbiome can wear down the gut’s protective lining. From there, toxins can move into the bloodstream and on to the organs. This can increase the risk of cancers both within the gastrointestinal tract and beyond. 

“Those toxins get into the bloodstream, and then they start to cause things to go awry beyond the gut microbiome,” she says.

Alcohol increases other long-term health risks

Beyond its link to cancer, alcohol is also linked to a variety of other health concerns, especially when consumed in excess, Karam-Hage says.

According to the Centers for Disease Control and Prevention (CDC), the long-term health risks of drinking excessive amounts of alcohol include: 

• high blood pressure
• heart disease
• stroke
• liver disease
• digestive problems
• weakened immune system

Alcohol affects sleep

If a drink or two leaves you ready for bed, you might be surprised to learn that drinking alcohol is linked to insomnia, or trouble falling — and staying — asleep. 

“The interesting thing about alcohol is that it’s sort of deceiving. When people drink, they feel sleepy or tired. They go to sleep, and then they have what we call rebound insomnia: in the second part of the night, they wake up and they cannot fall back asleep,” Karam-Hage explains.

Alcohol-related sleep issues aren’t just limited to nighttime, however. Karam-Hage says they can have a real impact during the daytime hours. “Insomnia can affect your day-to-day functioning,” he says.

Alcohol can have negative effects on fertility and pregnancy

Drinking alcohol can impact many stages of the journey to parenthood.

“There is the risk of infertility for both men and women,” Karam-Hage says. “But for women who get pregnant, a major problem is fetal alcohol syndrome.”

The CDC writes that fetal alcohol syndrome disorders may result in “lifelong physical, behavioral and intellectual disabilities,” which can occur when a fetus is exposed to the alcohol in a mother’s blood.

Drinking any amount of alcohol while pregnant can increase the risk of fetal alcohol syndrome disorders, Karam-Hage says. 

“It used to be thought that it’s only heavy alcohol use, but now the understanding is that any alcohol during pregnancy can expose the unborn fetus to fetal alcohol syndrome,” he says. 

In addition to the risk of fetal alcohol syndrome disorders, the CDC writes that drinking alcohol while pregnant can lead to miscarriage or stillbirth.

Alcohol impacts mental health and brain function

Alcohol can impact the brain in many ways. For example, Lee notes that heavy alcohol use can lead to:

• alcohol dependence 
• anxiety
• depression
• learning problems
• memory problems 

In addition to being a depressant, Karam-Hage says alcohol can cause brain atrophy by speeding up the death of neurons in the brain. The resulting damage to brain cells and cell death can reduce cognitive function and cause problems with memory, concentration and executive functioning. 

To date, research has mainly focused on excessive drinking; Karam-Hage says studies have even linked heavy drinking to increased dementia risk. More research is needed to determine how light alcohol use impacts the brain.

“Some people think that any alcohol causes some loss of neurons, which, of course it would because alcohol is toxic,” Karam-Hage says. “But the question is whether it's significant or not. That's the part that we don't know.”

How to proceed 

When it comes to preventing cancer, not drinking alcohol is the safest choice. 

Men who choose to drink should limit themselves to two drinks per day, while women who choose to drink should limit themselves to one drink per day.

A standard drink size looks different depending on the type of alcohol you choose. According to the CDC, a standard U.S. drink includes 0.6 ounces of pure alcohol; the same amount of pure alcohol is generally found in 12 ounces of beer, 5 ounces of wine and 1.5 ounces of 80-proof distilled spirits or liquor.

If you’d like to drink less, Lee notes there are many options you can try. 

“Try nonalcoholic beer or wine, replace a cocktail with a mixed drink that contains only a splash of alcohol or none at all or make several days out of the week alcohol free,” she says.

Request an appointment at MD Anderson online or call 1-877-632-6789.