NIAAA

U.S. Department of Health

and Human Services

National Institutes of Health

Beyond Hangovers

understanding

alcohol’s impact

on your health
Table of

contents

Beyond hangovers..........................................................................2
 

Effects on the brain........................................................................4
 

Effects on the heart ......................................................................9
 

Effects on the liver ......................................................................13
 

Effects on the pancreas ..............................................................15
 

Cancer risks..................................................................................17
 

Effects on the immune system ..................................................20
 

Additional resources ..................................................................23
 

Additional reading........................................................................24
 
Beyond

hangovers

A brightly colored cosmopolitan is the drink of choice for the

glamorous characters in Sex and the City. James Bond depends

on his famous martini—shaken, not stirred—to unwind with

after confounding a villain. And what wedding concludes

without a champagne toast?

Alcohol is part of our culture—it

helps us celebrate and socialize, and

it enhances our religious ceremonies.

But drinking too much—on a single

occasion or over time—can have

serious consequences for our health.

Most Americans recognize that

drinking too much can lead to

accidents and dependence. But that’s

only part of the story. In addition to

these serious problems, alcohol

abuse can damage organs, weaken

the immune system, and contribute

to cancers.

Plus, much like smoking, alcohol

affects different people differently.

Genes, environment, and even diet

can play a role in whether you

develop an alcohol­related disease.

On the flip side,some people actually

may benefit from drinking alcohol in

small quantities.

Sound complicated? It sure can be.

To stay healthy, and to decide what

role alcohol should play in your life, you

need accurate, up­to­date information.

This brochure is designed to offer you

guidance based on the latest research

on alcohol’s effect on your health.

2
A L I T T L E G O E S

A LO N G WAY:

K N O W T H E A M O U N T S

Knowing how much alcohol

constitutes a “standard” drink can

help you determine how much you are

drinking and understand the risks.

One standard drink contains about

0.6 fluid ounces or 14 grams of pure

alcohol. In more familiar terms, the

following amounts constitute one

standard drink:

• 12 fluid ounces of beer
 

(about 5% alcohol)
 

• 8 to 9 fluid ounces of malt liquor

(about 7% alcohol)

• 5 fluid ounces of table wine
 

(about 12% alcohol)
 

• 1.5 fluid ounces of hard liquor

(about 40% alcohol)

Research demonstrates “low­risk”

drinking levels for men are no more

than 4 drinks on any single day AND

no more than 14 drinks per week.

For women,“low­risk” drinking levels

=

are no more than three drinks on

any single day AND no more than

seven drinks per week. To stay

low­risk, you must keep within both

the single­day and weekly limits.

Even within these limits, you can

have problems if you drink too

quickly, have health conditions, or are

over age 65. Older adults should

have no more than three drinks on

any day and no more than seven

drinks per week.

Based on your health and how

alcohol affects you, you may need to

drink less or not at all. People who

should abstain from alcohol completely

include those who:

• Plan to drive a vehicle or operate

machinery

• Are pregnant or trying to
 

become pregnant
 

• Take medications that interact

with alcohol

• Have a medical condition that

alcohol can aggravate

12 fl oz of 

regular beer 

about 5% 

alcohol 

8–9 fl oz of 

malt liquor = (shown in a 

12 oz glass) 

about 7% 

alcohol 

t

5 fl oz of 

= able wine 

about 12% 

alcohol 

1.5 fl oz shot of 

80-proof spirits 

(“hard liquor”— 

whiskey, gin, rum, 

vodka, tequila, etc.) 

about 40% 

alcohol 

3
4

Effects on
 the brain
 

You’re chatting with friends at a

party and a waitress comes around

with glasses of champagne.You drink

one, then another, maybe even a few

more. Before you realize it, you are

laughing more loudly than usual and

swaying as you walk. By the end of

the evening, you are too slow to

move out of the way of a waiter with

a dessert tray and have trouble

speaking clearly. The next morning,

you wake up feeling dizzy and your

head hurts. You may have a hard time

remembering everything you did the

night before.

These reactions illustrate how

quickly and dramatically alcohol

affects the brain. The brain is an

intricate maze of connections that

keeps our physical and psychological

processes running smoothly. Disruption

of any of these connections can affect

how the brain works. Alcohol also

can have longer­lasting consequences

for the brain—changing the way it

looks and works and resulting in a

range of problems.

Most people do not realize how

extensively alcohol can affect the

brain. But recognizing these potential

consequences will help you make

better decisions about what amount

of alcohol is appropriate for you.

W H AT H A P P E N S

I N S I D E T H E B R A I N ?

The brain’s structure is complex. It

includes multiple systems that interact

to support all of your body’s

functions—from thinking to breathing

to moving.

These multiple brain systems

communicate with each other through

about a trillion tiny nerve cells called
neurons. Neurons in the brain translate

information into electrical and chemical

signals the brain can understand.

They also send messages from the

brain to the rest of the body.

Chemicals called neurotransmitters

carry messages between the neurons.

Neurotransmitters can be very

powerful. Depending on the type and

the amount of neurotransmitter,

these chemicals can either intensify

or minimize your body’s responses,

your feelings, and your mood.

The brain works to balance the

neurotransmitters that speed things

up with the ones that slow things

down to keep your body operating at

the right pace.

Alcohol can slow the pace

of communication between

neurotransmitters in the brain.

D I S C O V E R I N G T H E

B R A I N C H A N G E S

There still is much we do not

understand about how the brain

works and how alcohol affects it.

Researchers are constantly discovering

more about how alcohol interrupts

communication pathways in the brain

and changes brain structure, and the

resulting effects on behavior and

functioning. A variety of research

methods broaden our understanding

in different ways:

• BRAIN IMAGING – Various

imaging tools, including structural

magnetic resonance imaging

(MRI), functional magnetic

resonance imaging (fMRI), diffusion

tensor imaging (DTI), and positron

emission tomography (PET), are

used to create pictures of the

brain. MRI and DTI create images

of brain structure, or what the

brain looks like. fMRI looks at

brain function, or what the brain

is doing. It can detect changes

in brain activity. PET scans look

at changes in neurotransmitter

function.All of these imaging

techniques are useful to track

changes in the alcoholic brain. For

example, they can show how an

alcoholic brain changes immediately

after drinking stops, and again

after a long period of sobriety,

to check for possible relapses.

• PSYCHOLOGICAL TESTS –

Researchers also use psychological

tests to evaluate how alcohol­related

brain changes affect mental functioning.

These tests demonstrate how alcohol

affects emotions and personality,

as well as how it compromises

learning and memory skills.

• ANIMAL STUDIES – Testing the

effect of alcohol on animals’

5
brains helps researchers better

understand how alcohol injures the

human brain, and how abstinence

can reverse this damage.

D E F I N I N G T H E

B R A I N C H A N G E S

Using brain imaging and psychological

tests, researchers have identified the

regions of the brain most vulnerable

to alcohol’s effects.These include:

• CEREBELLUM – This area controls

motor coordination. Damage to

the cerebellum results in a loss

of balance and stumbling, and also

may affect cognitive functions

such as memory and emotional

response.

• LIMBIC SYSTEM – This complex

brain system monitors a variety

of tasks including memory and

emotion. Damage to this area

impairs each of these functions.

• CEREBRAL CORTEX – Our abilities

to think, plan, behave intelligently,

and interact socially stem from

this brain region. In addition,

this area connects the brain to

the rest of the nervous system.

Changes and damage to this

area impair the ability to solve

problems, remember, and learn.

A LC O H O L S H R I N K S

A N D D I S T U R B S

B R A I N T I S S U E

Heavy alcohol consumption—even

on a single occasion—can throw the

delicate balance of neurotransmitters

off course. Alcohol can cause your

neurotransmitters to relay information

too slowly, so you feel extremely

drowsy. Alcohol­related disruptions

to the neurotransmitter balance also

can trigger mood and behavioral

changes, including depression, agitation,

memory loss, and even seizures.

Long­term, heavy drinking causes

alterations in the neurons, such as

reductions in the size of brain cells.

As a result of these and other

changes, brain mass shrinks and the

brain’s inner cavity grows bigger.

These changes may affect a wide

range of abilities, including motor

coordination; temperature regulation;

sleep; mood; and various cognitive

functions, including learning and

memory.

One neurotransmitter particularly

susceptible to even small amounts of

alcohol is called glutamate. Among

other things, glutamate affects memory.

Researchers believe that alcohol

interferes with glutamate action, and

this may be what causes some people

to temporarily “black out,” or forget 6
much of what happened during a

night of heavy drinking.

Alcohol also causes an increased

release of serotonin, another

neurotransmitter, which helps regulate

emotional expression, and endorphins,

which are natural substances that

may spark feelings of relaxation and

euphoria as intoxication sets in.

Researchers now understand that

the brain tries to compensate for

these disruptions. Neurotransmitters

adapt to create balance in the brain

despite the presence of alcohol. But

making these adaptations can have

negative results, including building

alcohol tolerance, developing alcohol

dependence, and experiencing alcohol

withdrawal symptoms.

W H AT FA C TO R S
 

M A K E A D I F F E R E N C E ?
 

Different people react differently to

alcohol. That is because a variety of

factors can influence your brain’s response

to alcohol. These factors include:

• HOW MUCH AND HOW OFTEN

YOU DRINK – The more you drink,

the more vulnerable your brain is.

• YOUR GENETIC BACKGROUND

AND FAMILY HISTORY OF

ALCOHOLISM – Certain ethnic

populations can have stronger

reactions to alcohol, and children

of alcoholics are more likely to

become alcoholics themselves.

• YOUR PHYSICAL HEALTH –

If you have liver or nutrition

problems, the effects of alcohol

will take longer to wear off.

A R E B R A I N P R O B L E M S

R E V E R S I B L E ?

Abstaining from alcohol over several

months to a year may allow structural

brain changes to partially correct.

Abstinence also can help reverse

negative effects on thinking skills,

including problem­solving, memory,

and attention.

OT H E R A LC O H O L ­

R E L AT E D B R A I N

C O N D I T I O N S

LIVER DAMAGE THAT AFFECTS

THE BRAIN

Not only does alcoholic liver disease

affect liver function itself, it also

damages the brain. The liver breaks

down alcohol—and the toxins it

releases. During this process, alcohol’s

byproducts damage liver cells. These

damaged liver cells no longer function

as well as they should and allow too

much of these toxic substances,

ammonia and manganese in particular, 7
to travel to the brain.These substances

proceed to damage brain cells,

causing a serious and potentially

fatal brain disorder known as hepatic

encephalopathy.

Hepatic encephalopathy causes a

range of problems, from less severe

to fatal.These problems can include:

• Sleep disturbances

• Mood and personality changes

• Anxiety

• Depression

• Shortened attention span

• Coordination problems, including

asterixis, which results in hand

shaking or flapping

• Coma

• Death

Doctors can help treat hepatic

encephalopathy with compounds that

lower blood ammonia concentrations

and with devices that help remove

harmful toxins from the blood. In

some cases, people suffering from

hepatic encephalopathy require a

liver transplant, which generally

helps improve brain function.

F E TA L A LC O H O L

S P E C T R U M

D I S O R D E R S

Alcohol can affect the brain at any

stage of development—even before

birth. Fetal alcohol spectrum disorders

are the full range of physical, learning,

and behavioral problems, and other

birth defects that result from prenatal

alcohol exposure. The most serious

of these disorders, fetal alcohol

syndrome (FAS), is characterized by

abnormal facial features and is usually

associated with severe reductions in

brain function and overall growth.

FAS is the leading preventable birth

defect associated with mental and

behavioral impairment in the United

States today.

The brains of children with FAS are

smaller than normal and contain

fewer cells, including neurons. These

deficiencies result in life­long learning

and behavioral problems. Current

research is investigating whether the

brain function of children and adults

with FAS can be improved with

complex rehabilitative training, dietary

supplements, or medications.

8
Effects on
 the heart
 

Americans know how prevalent

heart disease is—about 1 in 12 of us

suffer from it. What we don’t always

recognize are the connections heart

disease shares with alcohol. On the

one hand, researchers have known

for centuries that excessive alcohol

consumption can damage the heart.

Drinking a lot over a long period of

time or drinking too much on a single

occasion can put your heart—and

your life—at risk. On the other hand,

researchers now understand that

drinking moderate amounts of alcohol

can protect the hearts of some

people from the risks of coronary

artery disease.

Deciding how much, if any, alcohol

is right for you can be complicated.

To make the best decision for

yourself, you need to know the facts

and then consult your physician.

KNOW THE FUNCTION:

Your cardiovascular system consists

of your heart, blood vessels, and

blood. This system works

constantly—every second of your

life—delivering oxygen and nutrients

to your cells, and carrying away carbon

dioxide and other unnecessary material.

Your heart drives this process. It is

a muscle that contracts and relaxes

over and over again, moving the

blood along the necessary path. Your

heart beats about 100,000 times

each day, pumping the equivalent of

2,000 gallons of blood throughout

your body.

The two sides, or chambers, of the

heart receive blood and pump it back

into the body. The right ventricle of

the heart pumps blood into the lungs

to exchange carbon dioxide from the

9
cells for oxygen. The heart relaxes

to allow this blood back into its

left chamber. It then pumps the

oxygen­rich blood to tissues and

organs. Blood passing through the

kidneys allows the body to get rid of

waste products. Electrical signals

keep the heart pumping continuously

and at the appropriate rate to

propel this routine.

K N O W T H E R I S K S :

ALCOHOLIC CARDIOMYOPATHY

Long­term heavy drinking weakens

the heart muscle, causing a condition

called alcoholic cardiomyopathy. A

weakened heart droops and stretches

and cannot contract effectively. As a

result, it cannot pump enough blood

to sufficiently nourish the organs.

In some cases, this blood flow

shortage causes severe damage to

organs and tissues. Symptoms of

cardiomyopathy include shortness of

breath and other breathing difficulties,

fatigue, swollen legs and feet, and

irregular heartbeat. It can even lead

to heart failure.

ARRHYTHMIAS

Both binge drinking and long­term

drinking can affect how quickly a

heart beats.The heart depends on an

internal pacemaker system to keep it

10 pumping consistently and at the right

speed. Alcohol disturbs this pacemaker

system and causes the heart to beat

too rapidly, or irregularly. These

heart rate abnormalities are called

arrhythmias. Two types of alcoholinduced arrhythmias are:

• ATRIAL FIBRILLATION – In this

form of arrhythmia, the heart’s

upper, or atrial, chambers shudder

weakly but do not contract.

Blood can collect and even clot

in these upper chambers. If a

blood clot travels from the heart

to the brain, a stroke can occur;

if it travels to other organs such

as the lungs, an embolism, or

blood vessel blockage, occurs.

• VENTRICULAR TACHYCARDIA –

This form of arrhythmia occurs in

the heart’s lower, or ventricular,

chambers. Electrical signals travel

throughout the heart’s muscles,

triggering contractions that keep

blood flowing at the right pace.

Alcohol­induced damage to heart

muscle cells can cause these

electrical impulses to circle through

the ventricle too many times,

causing too many contractions.

The heart beats too quickly, and

so does not fill up with enough

blood between each beat. As a

result, the rest of the body does
not get enough blood. Ventricular

tachycardia causes dizziness,

lightheadedness, unconsciousness,

cardiac arrest, and even sudden death.

Drinking to excess on a particular

occasion, especially when you generally don’t drink, can trigger either of

these irregularities. In these cases,

the problem is nicknamed “holiday

heart syndrome,” because people

who don’t usually drink may

consume too much alcohol at parties

during the holiday season.

Over the long­term, chronic drinking

changes the course of electrical

impulses that drive the heart’s beating,

which creates arrhythmia.

STROKES

A stroke occurs when blood cannot

reach the brain. In about 80 percent

of strokes, a blood clot prevents

blood flow to the brain. These are

called ischemic strokes. Sometimes,

blood accumulates in the brain, or in

the spaces surrounding it. This causes

hemorrhagic strokes.

Both binge drinking and long­term

heavy drinking can lead to strokes

even in people without coronary

heart disease. Recent studies show

that people who binge drink are

about 56 percent more likely than

people who never binge drink to

suffer an ischemic stroke over 10

years. Binge drinkers also are about

39 percent more likely to suffer any

type of stroke than people who

never binge drink.

In addition, alcohol exacerbates

the problems that often lead to

strokes, including hypertension,

arrhythmias, and cardiomyopathy.

HYPERTENSION

Chronic alcohol use, as well as

binge drinking, can cause high blood

pressure, or hypertension. Your blood

pressure is a measurement of the

pressure your heart creates as it

beats, and the pressure inside your

veins and arteries. Healthy blood

vessels stretch like elastic as the

heart pumps blood through them.

Hypertension develops when the

blood vessels stiffen, making

them less flexible. Heavy alcohol

consumption triggers the release of

certain stress hormones that in turn

constrict blood vessels.This elevates

blood pressure. In addition, alcohol

may affect the function of the

muscles within the blood vessels,

causing them to constrict and

elevate blood pressure.

K N OW T H E B E N E F I T S :

Research shows that healthy people

who drink moderate amounts of

alcohol may have a lower risk of

11
developing coronary heart disease

than nondrinkers. Moderate drinking

is usually defined as no more than

two drinks in a given day for men

and one drink per day for women

who are not pregnant or trying to

conceive.

A variety of factors, including diet,

genetics, high blood pressure, and

age, can cause fat to build up in your

arteries, resulting in coronary heart

disease. An excess of fat narrows the

coronary arteries, which are the

blood vessels that supply blood

directly to the heart. Clogged

arteries reduce blood supply to the

heart muscle, and make it easier for

blood clots to form. Blood clots can

lead to both heart attacks and strokes.

According to recent studies, drinking

moderately can protect your heart

from these conditions. Moderate

drinking helps inhibit and reduce the

build­up of fat in the arteries. It can

raise the levels of HDL—or “good”

cholesterol—in the blood, which

wards off heart disease. It can help

guard against heart attack and stroke

by preventing blood clots from forming

and by dissolving blood clots that do

develop. Drinking moderately also

may help keep blood pressure levels

in check.

These benefits may not apply

to people with existing medical

conditions, or who regularly take

certain medications. In addition,

researchers discourage people from

beginning to drink just for the

health benefits. Rather, you can use

this research to help you spark a

conversation with your medical

professional about the best

path for you.

12
Effects on
 the liver
 

K N O W T H E FA C T S :

Liver disease is one of the leading

causes of illness and death in the

United States. More than 2 million

Americans suffer from liver disease

caused by alcohol.

In general, liver disease strikes

people who drink heavily over many

years.

While many of us recognize that

excessive alcohol consumption can

lead to liver disease, we might not

know why. Understanding the

connections between alcohol and

the liver can help you make smarter

decisions about drinking and take

better control of your health.

KNOW THE FUNCTION:

Your liver works hard to keep your

body productive and healthy. It

stores energy and nutrients. It

generates proteins and enzymes your

body uses to function and ward off

disease. It also rids your body of

substances that can be dangerous—

including alcohol.

The liver breaks down most of the

alcohol a person consumes. But the

process of breaking alcohol down

generates toxins even more harmful

than alcohol itself. These by­products

damage liver cells, promote

inflammation, and weaken the body’s

natural defenses. Eventually, these

problems can disrupt the body’s

metabolism and impair the function

of other organs.

Because the liver plays such a vital

role in alcohol detoxification, it is

especially vulnerable to damage from

excessive alcohol. 13
K N O W T H E

C O N S E Q U E N C E S :

Heavy drinking—even for just a

few days at a time—can cause fat to

build up in the liver. This condition,

called steatosis, or fatty liver, is the

earliest stage of alcoholic liver

disease and the most common

alcohol­induced liver disorder. The

excessive fat makes it more difficult

for the liver to operate and leaves it

open to developing dangerous

inflammations, like alcoholic hepatitis.

For some, alcoholic hepatitis does

not present obvious symptoms. For

others, though, alcoholic hepatitis

can cause fever, nausea, appetite loss,

abdominal pain, and even mental

confusion. As it increases in severity,

alcoholic hepatitis dangerously enlarges

the liver, and causes jaundice, excessive

bleeding, and clotting difficulties.

Another liver condition associated

with heavy drinking is fibrosis, which

causes scar tissue to build up in the

liver. Alcohol alters the chemicals in

the liver needed to break down and

remove this scar tissue. As a result,

liver function suffers.

If you continue to drink, this

excessive scar tissue builds up and

creates a condition called cirrhosis,

which is a slow deterioration of the

liver. Cirrhosis prevents the liver

from performing critical functions,

including managing infections,removing

harmful substances from the blood,

and absorbing nutrients.

A variety of complications, including

jaundice, insulin resistance and type 2

diabetes, and even liver cancer, can

result as cirrhosis weakens liver function.

Risk factors ranging from genetics

and gender, to alcohol accessibility,

social customs around drinking, and

even diet can affect a person’s

individual susceptibility to alcoholic

liver disease. Statistics show that

about one in five heavy drinkers will

develop alcoholic hepatitis, while one

in four will develop cirrhosis.

K N O W T H E R E ’ S

A B R I G H T S I D E :

The good news is that a variety of

lifestyle changes can help treat alcoholic

liver disease. The most critical

lifestyle change is abstinence from

alcohol. Quitting drinking will help

prevent further injury to your liver.

Cigarette smoking, obesity, and poor

nutrition all contribute to alcoholic

liver disease. It is important to stop

smoking and improve your eating

habits to keep liver disease in check.

But when conditions like cirrhosis

become severe, a liver transplant

may be the primary treatment option.

14
Effects on

the pancreas

K N O W T H E FA C T S :

Each year, acute pancreatitis sends

more than 200,000 Americans to the

hospital. Many of those who suffer

from pancreatic problems are also

heavy drinkers. Habitual and excessive

drinking damages the pancreas, and

commonly causes pancreatitis.

Learning more about the links

between alcohol and pancreatic

problems can help you make better

decisions to protect your health.

KNOW THE FUNCTION:

The pancreas plays an important role

in food digestion and its conversion

into fuel to power your body. It

sends enzymes into the small intestine

to digest carbohydrates, proteins,

and fat. It also secretes insulin and

glucagon, hormones that regulate the

process of utilizing glucose, the

body’s main source of energy. Insulin

and glucagon control glucose levels,

which helps all cells use the energy

glucose provides. Insulin also ensures

that extra glucose gets stored away

as either glycogen or fat.

When you drink, alcohol damages

pancreatic cells and influences metabolic

processes involving insulin. This

process leaves the pancreas open to

dangerous inflammations.

K N O W T H E R I S K S :

A pancreas unaffected by alcohol

sends enzymes out to the small

intestine to metabolize food. Alcohol

jumbles this process. It causes the

pancreas to secrete its digestive

juices internally, rather than sending

the enzymes to the small intestine.

15
These enzymes, as well as acetaldehyde—

a substance produced from metabolizing,

or breaking down the alcohol—are

harmful to the pancreas. If you

consume alcohol excessively over a

long time, this continued process can

cause inflammation, as well as swelling

of tissues and blood vessels.

This inflammation is called pancreatitis,

and it prevents the pancreas from

working properly. Pancreatitis occurs

as a sudden attack, called acute

pancreatitis. As excessive drinking

continues, the inflammation can

become constant. This condition is

known as chronic pancreatitis.

Pancreatitis is also a risk factor for

the development of pancreatic cancer.

A heavy drinker may not be able

to detect the build­up of pancreatic

damage until the problems set off

an attack.

An acute pancreatic attack causes

symptoms including:

• Abdominal pain, which may

radiate up the back

• Nausea and vomiting

• Fever

• Rapid heart rate

• Diarrhea

• Sweating

Chronic pancreatitis causes these

symptoms as well as severe abdominal

pain,significant reduction in pancreatic

function and digestion, and blood

sugar problems. Chronic pancreatitis

can slowly destroy the pancreas and

lead to diabetes or even death.

While a single drinking binge will

not automatically lead to pancreatitis,

the risk of developing the disease

increases as excessive drinking

continues over time.

These risks apply to all heavy

drinkers, but only about 5 percent of

people with alcohol dependence

develop pancreatitis. Some people are

more susceptible to the disease than

others, but researchers have not yet

identified exactly what environmental

and genetic factors play the biggest role.

T R E AT M E N T H E L P S —

B U T D O E S N OT C U R E

Abstinence from alcohol can slow

the progression of pancreatitis and

reduce its painful symptoms.A low­fat

diet also may help. It is also critical to

guard against infections and to get

supportive treatment.Treatment options,

including enzyme­replacement therapy

or insulin, can improve pancreatic

function. In some cases, surgery is

necessary to relieve pain, clear

blockages, and reduce attacks.

The effects of alcoholic pancreatitis

can be managed, but not easily reversed. 16
Cancer

risks

K N O W T H E R I S K S :

Genetics, environment, and lifestyle

habits can all heighten your risk of getting

cancer.We can’t do anything to change

our genes, and we often can’t do much

to change our environment. But

lifestyle habits are a different story.

Drinking too much alcohol is one

lifestyle habit that can increase your

risk of developing certain cancers.

This does not mean that anyone who

drinks too much will develop cancer.

But numerous studies do show the

more you drink, the more you

increase your chances of developing

certain types of cancer.

For example, a group of Italy­based

scientists reviewed more than 200

studies examining alcohol’s impact

on cancer risk.The collective results

of these studies clearly demonstrate

that the more you drink, the higher

your risk for developing a variety of

cancers.The National Cancer Institute

identifies alcohol as a risk factor for

the following types of cancer:

• Mouth

• Esophagus

• Pharynx

• Larynx

• Liver

• Breast

At least 7 out of 10 people with

mouth cancer drink heavily. Drinking

five or more drinks per day can also

increase your risk of developing

other types of cancers, including

colon or rectal cancer. In fact,summary

estimates from the recent World

Cancer Research Fund report indicate

that women who drink five standard

17
alcohol drinks each day have about

1.2 times the risk of developing

colon or rectal cancer than women

who do not drink at all.

People who drink are also more

likely to smoke, and the combination

increases the risk significantly. Smoking

alone is a known risk factor for some

cancers. But smoking and drinking

together intensifies the cancer­causing

properties of each substance. The

overall effect poses an even greater risk.

The risk of throat and mouth cancers

is especially high because alcohol and

tobacco both come in direct contact

with those areas. Overall, people

who drink and smoke are 15 times

more likely to develop cancers of the

mouth and throat than nondrinkers and

nonsmokers. In addition, recent studies

estimate that alcohol and tobacco

together are responsible for:

• 80 percent of throat and mouth

cancer in men

• 65 percent of throat and mouth

cancer in women

• 80 percent of esophageal squamous

cell carcinoma, a type of esophagus

cancer

• 25 to 30 percent of all liver cancers

W O M E N A N D C A N C E R

One recent, groundbreaking study

18 followed the drinking habits of 1.2

million middle­aged women over 7

years. The study found that alcohol

increases women’s chances of

developing cancers of the breast, mouth,

throat, rectum, liver, and esophagus.

The researchers link alcohol to about

13 percent of these cancer cases.

In addition, the study concluded

that cancer risk increases no matter

how little or what kind of alcohol a

woman drinks. Even one drink a day

can raise risk, and it continues to

rise with each additional drink.While

men did not participate in this study,

the researchers believe this risk is

likely similar for men.

This study also attributes about

11 percent of all breast cancer cases

to alcohol. That means that of the

250,000 breast cancer cases

diagnosed in the United States in 2008,

about 27,000 may stem from alcohol.

K N O W T H E R E A S O N S :

Scientists are still trying to figure

out exactly how and why alcohol can

promote cancer. There are a variety

of possible explanations.

One explanation is that alcohol

itself is not the primary trigger for

cancer. We know that metabolizing,

or breaking down, alcohol results in

harmful toxins in the body. One of

these toxins is called acetylaldehyde.
Acetylaldehyde damages the genetic

material in cells—and renders the

cells incapable of repairing the damage.

It also causes cells to grow too

quickly, which makes conditions ripe

for genetic changes and mistakes.

Cancer can develop more easily in

cells with damaged genetic material.

In addition, recent animal studies

have shown that as cells try to break

down alcohol, they cause the body to

produce additional amounts of a

protein called vascular endothelial

growth factor (VEGF).VEGF promotes

the growth of blood vessels and

organ tissue. But, the flip side of

having too much VEGF is that it

allows blood vessels to grow in

cancer cells that would die on their

own. This allows the cancer cells to

develop into tumors.

We also know that alcohol can

damage the liver, causing cirrhosis.

Cirrhosis results when too much

scar tissue builds up within the liver

and leaves it unable to perform its

vital functions. One of the many

complications that can result from

cirrhosis is liver cancer.

Hormones may be the link

between alcohol and breast cancer.

Alcohol can increase the amounts of

some hormones in the body, including

estrogen. An excess of estrogen may

lead to breast cancer.

Finally, genetics may play a role in

preventing some heavy drinkers from

developing cancer. A European

research team examined 9,000 people

with similar lifestyle habits to determine

why some of them developed mouth

and throat cancers, and some did

not. Of the participants who were

heavy drinkers, those who did not

develop cancers had a particular

genetic alteration that enabled them

to break down alcohol about 100

times faster than in those without it.

The study suggested that this gene is

the reason why some people are less

likely to develop cancer in response to

heavy drinking.

K N O W T H E R E ’ S

A B R I G H T S I D E

Fortunately, studies show that you

can reduce your risk for cancer by

drinking less. A recent Canadian

report analyzed studies from 1966

through 2006 and concluded that

risk reduction is possible, specifically

for head and neck cancers.The study

found that as people abstained from

drinking, their risk for developing

cancer plunged. After 20 years of

abstinence, former drinkers had the

same risk for head and neck cancers

as people who never drank. 19
20

Effects on

the immune

system

Germs and bacteria surround us

everywhere. Luckily, our immune

system is designed to protect our

bodies from the scores of foreign

substances that can make us sick.

Drinking too much alcohol weakens

the immune system, making your

body a much easier target for disease.

Understanding the effect alcohol

can have on your immune system can

inform the decisions you make about

drinking alcohol.

K N O W T H E FA C T S :

Your immune system is often

compared to an army. This army

defends your body from infection

and disease. Your skin and the

mucous that lines your respiratory

and gastrointestinal tracts help block

bacteria from entering or staying in

your body. If foreign substances

somehow make it through these

barriers, your immune system kicks

into gear with two defensive systems:

innate and adaptive.

The innate system exists in your

body before you are exposed to

foreign substances like bacteria,

viruses, fungi, or parasites. These

substances, which are called antigens,

can invade your body and make you

sick. The components of the innate

system include:

• WHITE BLOOD CELLS – White
 

blood cells form your first line
 

of defense against infection.They
 

surround and swallow foreign
 

bodies quickly.
 

• NATURAL KILLER (NK) CELLS –

Natural Killers are special white
blood cells that detect and destroy

cells infected with cancer or

viruses.

• CYTOKINES – White blood cells

send out these chemical messengers

directly to an infected site.

Cytokines trigger inflammatory

responses, like dilating blood

vessels and increasing blood flow

to the affected area.They also

call on more white blood cells

to swarm an infected area.

The adaptive system kicks in after

you are exposed to an infection for

the first time. The next time you

encounter the same infection, your

adaptive system fights it off even

faster and more efficiently than the

first time. The components of the

adaptive system include:

• T­LYMPHOCYTE CELLS – T­cells

reinforce the work of white blood

cells by targeting individual foreign

substances.T­cells can identify and

destroy a vast array of bacteria and

viruses.They can also kill infected

cells and secrete cytokines.

• B­LYMPHOCYTE CELLS – B­cells

produce antibodies that fight off

harmful substances by sticking to

them and making them stand out

to other immune cells.

• ANTIBODIES – After B­cells
 

encounter antigens, they produce
 

antibodies.These are proteins that
 

target specific antigens and then
 

remember how to combat the antigen.
 

K N O W T H E R I S K S :

Alcohol suppresses both the innate

and the adaptive immune systems.

Chronic alcohol use reduces the

ability of white blood cells to effectively

engulf and swallow harmful bacteria.

Excessive drinking also disrupts the

production of cytokines, causing

your body to either produce too

much or not enough of these chemical

messengers. An abundance of

cytokines can damage your tissues,

whereas a lack of cytokines leaves

you open to infection.

Chronic alcohol use also

suppresses the development of T­cells

and may impair the ability of NK cells

to attack tumor cells. This reduced

function makes you more vulnerable

to bacteria and viruses, and less

capable of destroying cancerous cells.

With a compromised immune system,

chronic drinkers are more liable to

contract diseases like pneumonia and

tuberculosis than people who do not

drink too much. There is also data

linking alcohol’s damage to the

immune system with an increased

21
susceptibility to contracting HIV

infection. HIV develops faster in

chronic drinkers who already have

the virus.

Drinking a lot on a single occasion

also can compromise your immune

system. Drinking to intoxication can

slow your body’s ability to produce

cytokines that ward off infections by

causing inflammations.Without these

inflammatory responses, your body’s

ability to defend itself against bacteria

is significantly reduced.A recent study

shows that slower inflammatory

cytokine production can reduce your

ability to fight off infections for up to

24 hours after getting drunk.

S T I L L LO O K I N G F O R

T H E B R I G H T S I D E

At this point, scientists do not

know whether abstinence, reduced

drinking, or other measures will help

reverse the effects of alcohol on the

immune system.

Nevertheless, it is important to

keep in mind that avoiding drinking

helps minimize the burden on your

immune system, particularly if you are

fighting a viral or bacterial infection.

22
A

Additional

D D I T I O N A L 
 R

rEesour S O U R C E S ces
 MEDICAL AND

HEALTH INFORMATION

Brain:

National Institute

of Mental Health

www.nimh.nih.gov

866– 615–6464

National Institute of

Neurological Disorders

and Stroke

www.ninds.nih.gov

800–352–9424

Heart:

National Heart, Lung,

and Blood Institute

www.nhlbi.nih.gov

301–592–8573

Liver and Pancreas:

National Institute of Diabetes

and Digestive Diseases

www.niddk.nih.gov

301–496–3583

Cancer:

National Cancer Institute

www.cancer.gov

800–422–6237

Immune System:

National Institute of Allergies

and Infectious Diseases

www.niaid.nih.gov

866– 284 –4107

ALCOHOL AND ITS

HEALTH EFFECTS

National Institute on Alcohol

Abuse and Alcoholism

www.niaaa.nih.gov

301–443–3860

National Clearinghouse for

Alcohol and Drug Information

www.ncadi.samhsa.gov

800–729–6686

SUPPORT FOR REDUCING

OR QUITTING DRINKING

Rethinking Drinking

www.RethinkingDrinking.niaaa.nih.gov

23
Additional
 reading

Rethinking Drinking—offers researchbased information about risky drinking

patterns, how to recognize the signs of

an alcohol problem, and strategies for

cutting back or quitting drinking. Available

as a publication or interactiveWeb site

www.rethinkingdrinking.niaaa. nih.gov.

Harmful Interactions:
 

Mixing Alcohol With Medicines—
 

provides information on medications

and herbal preparations that may cause

harm when combined with alcohol.

A Family History of Alcoholism:

Are You at Risk?—describes how

heredity may increase the risk for

developing problems with alcohol and

how to limit that risk.

Alcohol: A Women’s Health Issue—

provides information on the effects of

alcohol on women’s health throughout

the lifespan, including the risks and

benefits of drinking.

Older Adults and Alcohol:

You Can Get Help—describes

how alcohol affects the health of

older drinkers and offers tips for

stopping or reducing drinking.

Drinking and Your

Pregnancy—explains how drinking

can hurt a developing baby, the problems

that children born with fetal alcohol

syndrome have, how to stop drinking, and

where to go for help.

Make a Difference: Talk to

Your Child About Alcohol—

offers guidance to parents and caregivers

of young people ages 10 to 14 on

preventing underage drinking.

To order, write to: National Institute

on Alcohol Abuse and Alcoholism,

Publications Distribution Center,

P.O. Box 10686, Rockville, MD

20849­0686.The full text of all of

the above publications is available on

NIAAA’sWeb site (www.niaaa.nih.gov).

24
NATIONAL INSTITUTE ON ALCOHOL ABUSE AND ALCOHOLISM
 

NIH Publication No. 10–7604

Revised May 2011