Alcohol (also known as ethanol) has a number of effects on health. Short-term effects of alcohol consumption include intoxication and dehydration. Long-term effects of alcohol consumption include changes in the metabolism of the liver and brain and alcoholism. Alcohol intoxication affects the brain, causing slurred speech, clumsiness, and delayed reflexes. Alcohol stimulates insulin production, which speeds up glucose metabolism and can result in low blood sugar, causing irritability and possibly death for diabetics. Even light and moderate alcohol consumption increases cancer risk in individuals. A 2014 World Health Organization report found that harmful alcohol consumption caused about 3.3 million deaths annually worldwide. Negative efforts are related to the amount consumed with no safe lower limit seen. Some nations have introduced alcohol packaging warning messages that inform consumers about alcohol and cancer, as well as foetal alcohol syndrome.
The median lethal dose of alcohol in test animals is a blood alcohol content of 0.45%. This is about six times the level of ordinary intoxication (0.08%), but vomiting or unconsciousness may occur much sooner in people who have a low tolerance for alcohol.
The high tolerance of chronic heavy drinkers may allow some of them to
remain conscious at levels above 0.40%, although serious health hazards
are incurred at this level.
Alcohol also limits the production of vasopressin (ADH) from the hypothalamus and the secretion of this hormone from the posterior pituitary gland. This is what causes severe dehydration when alcohol is consumed in large amounts. It also causes a high concentration of water in the urine and vomit and the intense thirst that goes along with a hangover.
Stress, hangovers, and the oral contraceptive pill
may increase the desire for alcohol because these things will lower the
level of testosterone and alcohol will acutely elevate it. Tobacco has the same effect of increasing the craving for alcohol.
Short-term effects
The short-term effects of alcohol
consumption range from a decrease in anxiety and motor skills at lower
doses to unconsciousness, anterograde amnesia, and central nervous
system depression at higher doses. Cell membranes are highly permeable to alcohol, so once alcohol is in the bloodstream it can diffuse into nearly every cell in the body.
The concentration of alcohol in blood is measured via blood alcohol content (BAC). The amount and circumstances of consumption play a large part in determining the extent of intoxication; for example, eating a heavy meal before alcohol consumption causes alcohol to absorb more slowly. Hydration also plays a role, especially in determining the extent of hangovers. After excessive drinking, unconsciousness can occur and extreme levels of consumption can lead to alcohol poisoning and death (a concentration in the blood stream of 0.40% will kill half of those affected). Alcohol may also cause death indirectly, by asphyxiation from vomit.
Alcohol can greatly exacerbate sleep problems. During abstinence, residual disruptions in sleep regularity and sleep patterns are the greatest predictors of relapse.
Long-term effects
According
to the World Health Organization's 2018 Global Status Report on Alcohol
and Health, there are more than 3 million people who die from the
harmful effects of alcohol each year, which amounts to more than 5% of
the burden of disease world-wide.
The US National Institutes of Health similarly estimates that 3.3
million deaths (5.9% of all deaths) were believed to be due to alcohol
each year.
Guidelines in the US and the UK advise that if people choose to drink, they should drink moderately.
Even light and moderate alcohol consumption increases cancer risk in individuals, especially with respect to squamous cell carcinoma of the esophagus, oropharyngeal cancer, and breast cancer.
A systematic analysis of data from the Global Burden of Disease Study, which was an observational study,
found that long term consumption of any amount of alcohol is associated
with an increased of risk of death in all people, and that even
moderate consumption appears to be risky. Similar to prior analyses, it
found an apparent benefit for older women in reducing the risks of death from ischemic heart disease
and from diabetes, but unlike prior studies it found those risks
cancelled by an apparent increased risk of death from breast cancer and
other causes.
A 2016 systematic review and meta-analysis found that moderate ethanol
consumption brought no mortality benefit compared with lifetime
abstention from ethanol consumption. Risk is greater in younger people due to binge drinking which may result in violence or accidents.
Long-term heavy use of alcohol damages nearly every organ and system in the body. Risks include alcoholism, malnutrition, chronic pancreatitis, alcoholic liver disease and cancer. In addition, damage to the central nervous system and peripheral nervous system can occur from chronic alcohol abuse.
The developing adolescent brain is particularly vulnerable to the toxic effects of alcohol.
Pregnancy
Medical organizations strongly discourage drinking alcohol during pregnancy. Alcohol passes easily from the mother's bloodstream through the placenta and into the bloodstream of the fetus, which interferes with brain and organ development.
Alcohol can affect the fetus at any stage during pregnancy, but the
level of risk depends on the amount and frequency of alcohol consumed.
Regular heavy drinking and binge drinking (four or more drinks on any
one occasion) pose the greatest risk for harm, but lesser amounts can
cause problems as well. There is no known safe amount or safe time to drink during pregnancy, and the U.S. CDC
recommends complete abstinence for women who are pregnant, trying to
become pregnant, or are sexually active and not using birth control.
Prenatal alcohol exposure can lead to fetal alcohol spectrum disorders (FASDs). The most severe form of FASD is fetal alcohol syndrome (FAS).[29] Problems associated with FASD include facial anomalies, low birth weight, stunted growth, small head size, delayed or uncoordinated motor skills, hearing or vision problems, learning disabilities, behavior problems, and inappropriate social skills compared to same-age peers. Those affected are more likely to have trouble in school, legal problems, participate in high-risk behaviors, and develop substance use disorders themselves.
Cardiovascular disease
In 2010, a systematic review reported that moderate consumption of
alcohol does not cause harm to people with cardiovascular disease.
However, the authors did not encourage people to start drinking alcohol
in hope of benefit. The position of the American Heart Association is that people who are currently nondrinkers should not start drinking alcohol.
Breastfeeding
The UK National Health Service
states that "an occasional drink is unlikely to harm" a breastfed baby,
and recommends consumption of "no more than one or two units of alcohol
once or twice a week" for breastfeeding mothers (where a pint of beer
or 50 ml drink of a spirit such as whisky corresponds to about two units of alcohol). The NHS also recommends to wait for a couple of hours before breastfeeding or express the milk into a bottle before drinking.
Researchers have shown that intoxicated breastfeeding reduces the
average milk expression but poses no immediate threat to the child as
the amount of transferred alcohol is insignificant.
Alcohol education
Alcohol education is the practice of disseminating information about
the effects of alcohol on health, as well as society and the family
unit. It was introduced into the public schools by temperance organizations such as the Woman's Christian Temperance Union in the late 19th century.
Initially, alcohol education focused on how the consumption of
alcoholic beverages affected society, as well as the family unit. In the 1930s, this came to also incorporate education pertaining to alcohol's effects on health. Organizations such as the National Institute on Alcohol Abuse and Alcoholism in the United States were founded to promulgate alcohol education alongside those of the temperance movement, such as the American Council on Alcohol Problems.
Alcohol expectations
Alcohol expectations are beliefs and attitudes
that people have about the effects they will experience when drinking
alcoholic beverages. They are just largely beliefs about alcohol's
effects on a person’s behaviors, abilities, and emotions. Some people
believe that if alcohol expectations can be changed, then alcohol abuse might be reduced. Men tend to become more aggressive in laboratory studies in which they are drinking only tonic water
but believe that it contains alcohol. They also become less aggressive
when they believe they are drinking only tonic water, but are actually
drinking tonic water that contains alcohol.
The phenomenon of alcohol expectations recognizes that
intoxication has real physiological consequences that alter a drinker's
perception of space and time, reduce psychomotor skills, and disrupt equilibrium.
The manner and degree to which alcohol expectations interact with the
physiological short-term effects of alcohol, resulting in specific
behaviors, is unclear.
A single study found that if a society believes that intoxication leads to sexual behavior,
rowdy behavior, or aggression, then people tend to act that way when
intoxicated. But if a society believes that intoxication leads to
relaxation and tranquil behavior, then it usually leads to those
outcomes. Alcohol expectations vary within a society, so these outcomes
are not certain.
People tend to conform to social expectations, and some societies
expect that drinking alcohol will cause disinhibition. However, in
societies in which the people do not expect that alcohol will
disinhibit, intoxication seldom leads to disinhibition and bad behavior.
Alcohol expectations can operate in the absence of actual
consumption of alcohol. Research in the United States over a period of
decades has shown that men tend to become more sexually aroused when
they think they have been drinking alcohol—even when they have not been
drinking it. Women report feeling more sexually aroused when they
falsely believe the beverages they have been drinking contained alcohol
(although one measure of their physiological arousal shows that they
became less aroused).
Drug treatment programs
Most
addiction treatment programs encourage people with drinking problems to
see themselves as having a chronic, relapsing disease that requires a
lifetime of attendance at 12-step meetings to keep in check. However,
some people do not develop lifelong problems.
Alcohol abuse
Addiction
experts in psychiatry, chemistry, pharmacology, forensic science,
epidemiology, and the police and legal services engaged in delphic analysis regarding 20 popular recreational drugs. Alcohol was ranked 6th in dependence, 11th in physical harm, and 2nd in social harm.
Recommended maximum intake
Binge drinking is becoming a major problem in the UK. Advice on weekly consumption is avoided in United Kingdom.
Since 1995 the UK government has advised that regular consumption
of three to four units (one unit equates to 10 mL of pure ethanol) a
day for men and or two to three units for women, would not pose
significant health risks. However, consistently drinking more than four
units a day (for men) and three units (women), is not advisable.
Previously (from 1992 until 1995), the advice was that men should
drink no more than 21 units per week, and women no more than 14.
(The difference between the sexes was due to the typically lower weight
and water-to-body-mass ratio of women.) This was changed because a
government study showed that many people were in effect "saving up"
their units and using them at the end of the week, a phenomenon referred
to as binge drinking. The Times reported in October 2007 that these limits had been "plucked out of the air" and had no scientific basis.
Sobriety
A midshipman is subjected to a random breathalyzer test to determine sobriety.
Sobriety is the condition of not having any measurable levels, or effects from mood-altering drugs. According to WHO "Lexicon of alcohol and drug terms..." sobriety is continued abstinence from psychoactive drug use.
Sobriety is also considered to be the natural state of a human being
given at a birth. In a treatment setting, sobriety is the achieved goal
of independence from consuming or craving mind-altering substances. As
such, sustained abstinence is a prerequisite for sobriety. Early in
abstinence, residual effects of mind-altering substances can preclude
sobriety. These effects are labeled "PAWS", or "post acute withdrawal
syndrome". Someone who abstains, but has a latent desire to resume use,
is not considered truly sober. An abstainer may be subconsciously
motivated to resume drug use, but for a variety of reasons, abstains
(e.g. such as a medical or legal concern precluding use). Sobriety has more specific meanings within specific contexts, such as the culture of Alcoholics Anonymous,
other 12 step programs, law enforcement, and some schools of
psychology. In some cases, sobriety implies achieving "life balance".
Injury and deaths
Injury
is defined as physical damage or harm that is done or sustained. The
potential of injuring oneself or others can be increased after consuming
alcohol due to the certain short term effects related to the substance
such as lack of coordination, blurred vision, and slower reflexes to
name a few.
Due to these effects the most common injuries include head, fall, and
vehicle-related injuries. A study was conducted of patients admitted to
the Ulster Hospital
in Northern Ireland with fall related injuries. They found that 113 of
those patients admitted to that hospital during that had consumed
alcohol recently and that the injury severity was higher for those that
had consumed alcohol compared to those that had not. Another study showed that 21% of patients admitted to the Emergency Department of the Bristol Royal Infirmary
had either direct or indirect alcohol related injuries. If these
figures are extrapolated it shows that the estimated number of patients
with alcohol related injuries are over 7,000 during the year at this
emergency department alone.
In the United States alcohol resulted in about 88,000 deaths in 2010. The World Health Organization
calculated that more than 3 million people, mostly men, died as a
result of harmful use of alcohol in 2016. This was about 13.5 % of the
total deaths of people between 20 and 39. More than 5% of the global
disease burden was caused by the harmful use of alcohol.
Genetic differences
Alcohol flush and respiratory reactions
Alcohol flush reaction is a condition in which an individual's face
or body experiences flushes or blotches as a result of an accumulation
of acetaldehyde,
a metabolic byproduct of the catabolic metabolism of alcohol. It is
best known as a condition that is experienced by people of Asian
descent. According to the analysis by HapMap Project,
the rs671 allele of the ALDH2 gene responsible for the flush reaction
is rare among Europeans and Africans, and it is very rare among
Mexican-Americans. 30% to 50% of people of Chinese and Japanese ancestry
have at least one ALDH*2 allele.
The rs671 form of ALDH2, which accounts for most incidents of alcohol
flush reaction worldwide, is native to East Asia and most common in
southeastern China. It most likely originated among Han Chinese in
central China,
and it appears to have been positively selected in the past. Another
analysis correlates the rise and spread of rice cultivation in Southern
China with the spread of the allele.
The reasons for this positive selection aren't known, but it's been
hypothesized that elevated concentrations of acetaldehyde may have
conferred protection against certain parasitic infections, such as Entamoeba histolytica.
The same SNP allele of ALDH2, also termed glu487lys, and the abnormal
accumulation of acetaldehyde following the drinking of alcohol, is
associated with the alcohol-induced respiratory reactions of rhinitis and asthma that occur in Eastern Asian populations.
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Metabolism of alcohol (ethanol) to acetaldehyde (ethanal) and then acetic acid (ethanoic acid)
American Indian alcoholism
While little detailed genetic research has been done, it has been
shown that alcoholism tends to run in families with possible involvement
of differences in alcohol metabolism and the genotype of
alcohol-metabolizing enzymes.
Genetics and amount of consumption
Having
a particular genetic variant (A-allele of ADH1B rs1229984) is
associated with non-drinking and lower alcohol consumption. This variant
is also associated with favorable cardiovascular profile and a reduced
risk of coronary heart disease compared to those without the genetic
variant, but it is unknown whether this may be caused by differences in
alcohol consumption or by additional confounding effects of the genetic variant itself.
Gender differences
Historically, according to the British Medical Journal,
"men have been far more likely than women to drink alcohol and to drink
it in quantities that damage their health, with some figures suggesting
up to a 12-fold difference between the sexes". However, analysis of data collected over a century from multiple countries suggests that the gender gap in alcohol consumption
is narrowing, and that young women (born after 1981) are consuming
alcohol more than their male counterparts. Such findings have
implications for the way in which alcohol-use prevention and
intervention programs are designed and implemented.
Alcoholism
Based on combined data from SAMHSA's 2004-2005 National Surveys on Drug Use & Health, the rate of past year alcohol dependence
or abuse among people aged 12 or older varied by level of alcohol use:
44.7% of past month heavy drinkers, 18.5% binge drinkers, 3.8% past
month non-binge drinkers, and 1.3% of those who did not drink alcohol in
the past month met the criteria for alcohol dependence or abuse in the
past year. Males had higher rates than females for all measures of
drinking in the past month: any alcohol use (57.5% vs. 45%), binge
drinking (30.8% vs. 15.1%), and heavy alcohol use (10.5% vs. 3.3%), and
males were twice as likely as females to have met the criteria for
alcohol dependence or abuse in the past year (10.5% vs. 5.1%).
Over time the difference between males and females has narrowed.
According to a 2016 systematic review, for those born at the end of the
20th century men were 1.2 times as likely to drink to problematic
levels, and 1.3 times as likely to develop health problems from
drinking.
Sensitivity
Several biological factors make women more vulnerable to the effects of alcohol than men.
- Body fat. Women tend to weigh less than men, and—pound for pound—a woman’s body contains less water and more fatty tissue than a man’s. Because fat retains alcohol while water dilutes it, alcohol remains at higher concentrations for longer periods of time in a woman’s body, exposing her brain and other organs to more alcohol.
- Enzymes. Women have lower levels of two enzymes—alcohol dehydrogenase and aldehyde dehydrogenase—that metabolize (break down) alcohol in the stomach and liver. As a result, women absorb more alcohol into their bloodstreams than men.
- Hormones. Changes in hormone levels during the menstrual cycle may also affect how a woman metabolizes alcohol.
Metabolism
Females
demonstrated a higher average rate of elimination (mean, 0.017; range,
0.014–0.021 g/210 L) than males (mean, 0.015; range, 0.013–0.017 g/210
L). Female subjects on average had a higher percentage of body fat
(mean, 26.0; range, 16.7–36.8%) than males (mean, 18.0; range,
10.2–25.3%).
Depression
The
link between alcohol consumption, depression, and gender was examined
by the Centre for Addiction and Mental Health (Canada). The study found
that women taking antidepressants consumed more alcohol than women who
did not experience depression as well as men taking antidepressants. The
researchers, Dr. Kathryn Graham and a PhD Student Agnes Massak analyzed
the responses to a survey by 14,063 Canadian residents aged 18–76
years. The survey included measures of quantity, frequency of drinking,
depression and antidepressants use, over the period of a year. The
researchers used data from the GENACIS Canada survey, part of an
international collaboration to investigate the influence of cultural
variation on gender differences in alcohol use and related problems. The
purpose of the study was to examine whether, like in other studies
already conducted on male depression and alcohol consumption, depressed
women also consumed less alcohol when taking anti-depressants. According
to the study, both men and women experiencing depression (but not on
anti-depressants) drank more than non-depressed counterparts. Men taking
antidepressants consumed significantly less alcohol than depressed men
who did not use antidepressants. Non-depressed men consumed 436 drinks
per year, compared to 579 drinks for depressed men not using
antidepressants, and 414 drinks for depressed men who used
antidepressants. Alcohol consumption remained higher whether the
depressed women were taking anti-depressants or not. 179 drinks per year
for non-depressed women, 235 drinks for depressed women not using
antidepressants, and 264 drinks for depressed women who used
antidepressants. The lead researcher argued that the study "suggests
that the use of antidepressants is associated with lower alcohol
consumption among men suffering from depression. But this does not
appear to be true for women."
