The inverse relation in Western cultures between alcohol consumption
and cardiovascular disease has been known for over 100 years.
[9]
Many physicians do not promote alcohol consumption, however, given the
many health concerns associated with it. Some suggest that alcohol
should be regarded as a recreational drug, and prefer exercise and good
nutrition to combat cardiovascular disease.
[10][11]
Others have argued that the benefits of moderate alcohol consumption
may be outweighed by other increased risks, including those of
injuries,
violence,
fetal damage,
liver disease, and certain forms of
cancer.
[12]
The adverse effects of long-term excessive use of alcohol are close
to those seen with other sedative-hypnotics (apart from organ toxicity
which is much more problematic with alcohol).
Withdrawal effects and dependence are also almost identical.
[13] Alcohol at moderate levels has some positive and negative effects on health. The negative effects include increased risk of
liver diseases,
oropharyngeal cancer,
esophageal cancer and
pancreatitis. Conversely moderate intake of alcohol may have some beneficial effects on
gastritis and
cholelithiasis.
[14]
Of the total number of deaths and diseases caused by alcohol, most
happen to the majority of the population who are moderate drinkers,
rather than the heavy drinker minority.
[15]
Chronic alcohol misuse and abuse has serious effects on physical and
mental health. Chronic excess alcohol intake, or alcohol dependence, can
lead to a wide range of
neuropsychiatric or
neurological impairment,
cardiovascular disease,
liver disease, and
malignant neoplasms. The psychiatric disorders which are associated with alcoholism include
major depression,
dysthymia,
mania,
hypomania,
panic disorder,
phobias,
generalized anxiety disorder,
personality disorders,
schizophrenia,
suicide,
neurologic deficits (e.g. impairments of
working memory,
emotions,
executive functions,
visuospatial abilities and
gait and
balance) and
brain damage. Alcohol dependence is associated with
hypertension,
coronary heart disease, and
ischemic stroke,
cancer of the
respiratory system, and also
cancers of the
digestive system,
liver,
breast and
ovaries. Heavy drinking is associated with
liver disease, such as
cirrhosis.
[16] Excessive alcohol consumption can have a negative
impact on aging.
[17]
Recent studies have focused on understanding the mechanisms by which
moderate alcohol consumption confers cardiovascular benefit.
[18] One study has suggested a beneficial effect of alcohol on patients with hypertension.
[19]
Peripheral arterial disease
"Moderate alcohol consumption appears to decrease the risk of PAD in apparently healthy men."
[61]
"In this large population-based study, moderatable alcohol consumption
was inversely associated with peripheral arterial disease in women but
not in men. Residual confounding by smoking may have influenced the
results. Among nonsmokers an inverse association was found between
alcohol consumption and peripheral arterial disease in both men and
women."
[62][63]
Intermittent claudication
A study found that moderate consumption of alcohol had a protective effect against
intermittent claudication. The lowest risk was seen in men who drank 1 to 2 drinks per day and in women who drank half to 1 drink per day.
[64]
Heart attack and stroke
Drinking in moderation has been found to help those who have suffered a
heart attack survive it.
[65][66][67] However, excessive alcohol consumption leads to an increased risk of
heart failure.
[68]
A review of the literature found that half a drink of alcohol offered
the best level of protection. However, they noted that at present there
have been no randomised trials to confirm the evidence which suggests a
protective role of low doses of alcohol against heart attacks.
[69] However, moderate alcohol consumption is associated with hypertension.
[12] There is an increased risk of
hypertriglyceridemia,
cardiomyopathy,
hypertension, and
stroke if 3 or more
standard drinks of alcohol are taken per day.
[70]
Cardiomyopathy
Large amount of alcohol over the long term can lead to alcoholic
cardiomyopathy. Alcoholic cardiomyopathy presents in a manner clinically identical to idiopathic
dilated cardiomyopathy, involving hypertrophy of the musculature of the heart that can lead to congestive heart failure.
[71]
Hematologic diseases
Nervous system
Results of the
ISCD
2010 study ranking the levels of damage caused by drugs, in the opinion
of drug-harm experts. When harm to self and others is summed, alcohol
was the most harmful of all drugs considered, scoring 72%.
Chronic heavy alcohol consumption impairs brain development, causes
brain shrinkage,
dementia,
physical dependence, increases neuropsychiatric and cognitive disorders and causes distortion of the
brain chemistry.
At present, due to poor study design and methodology, the literature is
inconclusive on whether moderate alcohol consumption increases the risk
of dementia or decreases it.
[73]
Evidence for a protective effect of low to moderate alcohol consumption
on age related cognitive decline and dementia has been suggested by
some research, however, other research has not found a protective effect
of low to moderate alcohol consumption.
[74] Some evidence suggests that low to moderate alcohol consumption may speed up brain volume loss.
[75] Chronic consumption of alcohol may result in increased plasma levels of the toxic amino acid
homocysteine;
[76][77] which may explain alcohol withdrawal seizures,
[78] alcohol-induced brain atrophy
[79] and alcohol-related cognitive disturbances.
[80] Alcohol's impact on the nervous system can also include disruptions of
memory and
learning (
see Effects of alcohol on memory), such as resulting in a
blackout phenomenon.
Strokes
Epidemiological studies of middle-aged populations generally find the
relationship between alcohol intake and the risk of stroke to be either
U- or J-shaped.
[81][82][83][84]
There may be very different effects of alcohol based on the type of
stroke studied. The predominate form of stroke in Western cultures is
ischemic, whereas non-western cultures have more hemorrhagic stroke. In
contrast to the beneficial effect of alcohol on ischemic stroke,
consumption of more than 2 drinks per day increases the risk of
hemorrhagic stroke. The National Stroke Association estimates this
higher amount of alcohol increases stroke risk by 50%.
[85]
"For stroke, the observed relationship between alcohol consumption and
risk in a given population depends on the proportion of strokes that are
hemorrhagic. Light-to-moderate alcohol intake is associated with a
lower risk of ischemic stroke which is likely to be, in part, causal.
Hemorrhagic stroke, on the other hand, displays a loglinear relationship
with alcohol intake."
[86]
Brain
Alcohol abuse is associated with widespread and significant brain
lesions.
Alcohol related brain damage is not only due to the direct toxic
effects of alcohol; alcohol withdrawal, nutritional deficiency,
electrolyte disturbances, and liver damage are also believed to
contribute to alcohol-related brain damage.
[87] The long-term effects of alcohol on brain chemistry is an important cause of
chronic fatigue.
[88]
Cognition and dementia
Excessive alcohol intake is associated with impaired
prospective memory.
This impaired cognitive ability leads to increased failure to carry out
an intended task at a later date, for example, forgetting to lock the
door or to post a letter on time. The higher the volume of alcohol
consumed and the longer consumed, the more severe the impairments.
[89]
One of the organs most sensitive to the toxic effects of chronic
alcohol consumption is the brain. In France approximately 20% of
admissions to mental health facilities are related to alcohol-related
cognitive impairment, most notably alcohol-related dementia. Chronic
excessive alcohol intake is also associated with serious cognitive
decline and a range of neuropsychiatric complications. The elderly are
the most sensitive to the toxic effects of alcohol on the brain.
[90]
There is some inconclusive evidence that small amounts of alcohol taken
in earlier adult life is protective in later life against cognitive
decline and dementia.
[91]
However, a study concluded, "Our findings suggest that, despite
previous suggestions, moderate alcohol consumption does not protect
older people from cognitive decline."
[92]
Acetaldehyde
is produced from ethanol metabolism by the liver. The acetaldehyde is
further metabolized by the enzyme acetaldehyde dehydrogenase. A
deficiency of this enzyme is not uncommon in individuals from
Northeastern Asia as pointed out in a study from Japan.
[93] This study has suggested these individuals may be more susceptible to late-onset
Alzheimer's disease,
however this higher risk is associated with the enzyme deficiency not
with alcohol consumption. Individuals with this defect generally do not
drink alcohol.
Essential tremor
Essential tremors can be temporarily relieved in up to two-thirds of patients by drinking small amounts of alcohol.
[96]
Ethanol is known to activate aminobutyric acid type A (GABAA) and
inhibit N-methyl-D-aspartate (NMDA) glutamate receptors, which are both
implicated in essential tremor pathology
[97] and could underlie the ameliorative effects.
[98][99] Additionally, the effects of ethanol have been studied in different animal essential tremor models.
Sleep
Chronic use of alcohol used to induce sleep can lead to
insomnia. Frequent moving between sleep stages occurs, with awakenings due to headaches and
diaphoresis.
Stopping chronic alcohol abuse can also lead to profound disturbances
of sleep with vivid dreams. Chronic alcohol abuse is associated with
NREM stage 3 and 4 sleep as well as suppression of
REM sleep and REM sleep fragmentation. During withdrawal REM sleep is typically exaggerated as part of a
rebound effect.
[100]
Mental health effects
High rates of
major depressive disorder
occur in heavy drinkers and those who abuse alcohol. Whether it is more
true that major depressive disorder causes self-medicating alcohol
abuse, or the increased incidence of the disorder in alcohol abusers is
caused by the drinking, is not known though some evidence suggests
drinking causes the disorder.
[101] Alcohol misuse is associated with a number of mental health disorders and alcoholics have a very high
suicide rate.
[102]
A study of people hospitalised for suicide attempts found that those
who were alcoholics were 75 times more likely to go on to successfully
commit suicide than non-alcoholic suicide attempters.
[103]
In the general alcoholic population the increased risk of suicide
compared to the general public is 5-20 times greater. About 15 percent
of alcoholics commit suicide. Abuse of other drugs is also associated
with an increased risk of suicide. About 33 percent of suicides in the
under 35s are due to alcohol or other substance misuse.
[104]
Social skills
are significantly impaired in people suffering from alcoholism due to
the neurotoxic effects of alcohol on the brain, especially the
prefrontal cortex area of the brain. The social skills that are impaired by
alcohol abuse include impairments in perceiving facial emotions, prosody perception problems and
theory of mind deficits; the ability to understand humour is also impaired in alcohol abusers.
[105]
Studies have shown that alcohol dependence relates directly to
cravings and
irritability.
[106] Another study has shown that alcohol use is a significant predisposing factor towards
antisocial behavior in children.
[107]
Depression, anxiety and panic disorder are disorders commonly reported
by alcohol dependent people. Alcoholism is associated with dampened
activation in brain networks responsible for emotional processing (
e.g. the
amygdala and
hippocampus).
[108]
Evidence that the mental health disorders are often induced by alcohol
misuse via distortion of brain neurochemistry is indicated by the
improvement or disappearance of symptoms that occurs after prolonged
abstinence, although problems may worsen in early withdrawal and
recovery periods.
[109][110][111]
Psychosis is secondary to several alcohol-related conditions including
acute intoxication and withdrawal after significant exposure.
[112]
Chronic alcohol misuse can cause psychotic type symptoms to develop,
more so than with other drugs of abuse. Alcohol abuse has been shown to
cause an 800% increased risk of psychotic disorders in men and a 300%
increased risk of psychotic disorders in women which are not related to
pre-existing psychiatric disorders. This is significantly higher than
the increased risk of psychotic disorders seen from cannabis use making
alcohol abuse a very significant cause of psychotic disorders.
[113]
Approximately 3 percent of people who are alcohol dependent experience
psychosis during acute intoxication or withdrawal. Alcohol-related
psychosis may manifest itself through a
kindling mechanism. The mechanism of alcohol-related psychosis is due to distortions to neuronal membranes,
gene expression, as well as
thiamin
deficiency. It is possible in some cases that alcohol abuse via a
kindling mechanism can cause the development of a chronic
substance-induced psychotic disorder, i.e.
schizophrenia.
The effects of an alcohol-related psychosis include an increased risk
of depression and suicide as well as psychosocial impairments.
[112] However, moderate wine drinking has been shown to lower the risk for depression.
[114]
While
alcohol
initially helps social phobia or panic symptoms, with longer term
alcohol misuse can often worsen social phobia symptoms and can cause
panic disorder to develop or worsen, during alcohol intoxication and
especially during the
alcohol withdrawal syndrome.
This effect is not unique to alcohol but can also occur with long term
use of drugs which have a similar mechanism of action to alcohol such as
the
benzodiazepines which are sometimes prescribed as tranquillisers to people with alcohol problems.
[115] Approximately half of patients attending mental health services for conditions including
anxiety disorders such as
panic disorder or
social phobia suffer from alcohol or
benzodiazepine dependence.
It was noted that every individual has an individual sensitivity level
to alcohol or sedative hypnotic drugs and what one person can tolerate
without ill health another will suffer very ill health and that even
moderate drinking can cause
rebound anxiety
syndromes and sleep disorders. A person who is suffering the toxic
effects of alcohol will not benefit from other therapies or medications
as they do not address the root cause of the symptoms.
[116]
Digestive system and weight gain
The impact of alcohol on weight-gain is contentious: some studies find no effect,
[117] others find decreased
[118] or increased effect on weight gain.
Metabolic syndrome
A study concluded, "Mild to moderate alcohol consumption is associated with a lower prevalence of the
metabolic syndrome,
with a favorable influence on lipids, waist circumference, and fasting
insulin. This association was strongest among whites and among beer and
wine drinkers."
[121]
This is also true for Asians. A J-curve association between alcohol
intake and metabolic syndrome was found: "The results of the present
study suggest that the metabolic syndrome is negatively associated with
light alcohol consumption (1–15 g alcohol/d) in Korean adults". However,
"odds ratios for the metabolic syndrome and its components tended to
increase with increasing alcohol consumption."
[122]
Gallbladder effects
Research has found that drinking reduces the risk of developing
gallstones.
Compared with alcohol abstainers, the relative risk of gallstone
disease, controlling for age, sex, education, smoking, and body mass
index, is 0.83 for occasional and regular moderate drinkers (< 25 ml
of ethanol per day), 0.67 for intermediate drinkers (25-50 ml per day),
and 0.58 for heavy drinkers. This inverse association was consistent
across strata of age, sex, and body mass index."
[123]
Frequency of drinking also appears to be a factor. "An increase in
frequency of alcohol consumption also was related to decreased risk.
Combining the reports of quantity and frequency of alcohol intake, a
consumption pattern that reflected frequent intake (5-7 days/week) of
any given amount of alcohol was associated with a decreased risk, as
compared with nondrinkers. In contrast, infrequent alcohol intake (1-2
days/week) showed no significant association with risk."
[124]
Liver disease
Alcoholic liver disease
is a major public health problem. For example in the United States up
to two million people have alcohol-related liver disorders.
[127] Chronic alcohol abuse can cause
fatty liver,
cirrhosis and
alcoholic hepatitis.
Treatment options are limited and consist of most importantly
discontinuing alcohol consumption. In cases of severe liver disease, the
only treatment option may be a
liver transplant in alcohol abstinent patients. Research is being conducted into the effectiveness of
anti-TNFs. Certain complementary medications, e.g.,
milk thistle and
silymarin, appear to offer some benefit.
[127][128] Alcohol is a leading cause of
liver cancer
in the Western world, accounting for 32-45% of hepatic cancers. Up to
half a million people in the United States develop alcohol-related
liver cancer.
[129][130] Moderate alcohol consumption also increases the risk of liver disease.
[12]
Pancreatitis
