Alcohol Facts

Fossilized teeth show that fruit was a major component in the primate diet between 45 million and 34 million years ago, and some of the closest ancestors of human species—gorillas, chimpanzees, and orangutans—ate diets based on fruit. Primates are known to have a higher olfactory sensitivity to alcohol than other mammals. As human evolution continued, fruits were mostly replaced by roots, tubers, and meat. Although our ancestors stopped relying heavily on fruit, it is possible that the taste for alcohol arose during our long-shared ancestry with primates.


Monkeys usually prefer ripe fruits with approximately 1 percent alcohol content but avoid overripe fruits with 4 percent alcohol and lower sugar content. Anecdotally, humans often consume alcohol with food, suggesting that drinking with food is a natural combination. For millions of years, the amount of alcohol consumed by our ancestors was strictly limited, and the situation did not change even 10,000 years ago when humans became agriculturists and could produce plenty of barley and malt, the raw material for fermentation. Yeasts stop producing alcohol when the alcohol level reaches between 10 and 15 percent because yeasts start dying at this alcohol concentration. Ancient beers and wines probably contained only 5 percent alcohol until alcohol distillation was invented in Central Asia around AD 700. Then drinks with a higher alcohol content became available and the history of alcohol abuse by humans began.
The first historical evidence of alcoholic beverages came from an ar-chaeological discovery of Stone Age beer jugs from approximately 10,000 years ago. The first palm date wine was probably brewed in Mesopotamia. Evidence of wine appeared in Egypt about 5,000 years ago—Osiris was worshipped as a wine god throughout the nation. beer was probably brewed in ancient Egypt and both wine and beer were offered to the gods. Egyptians used alcoholic beverages for pleasure and rituals, and for medical and nutritional purposes. However, even in ancient times the Egyptians were aware of the harmful effect of excess consumption of alcohol and emphasis was on moderate use. The earliest evidence of alcohol use in China dates back to 5000 BC when alcohol was mainly produced from rice, honey, and fruits. A Chinese imperial edict ca. 1116 BC made it clear that the use of alcohol in moderation was the key and was prescribed from the heavens. In ancient India, alcoholic beverages were known as “sura,” a favorite drink of Indra, the king of all gods and goddesses. Use of such drinks was known in 3000–2000 BC, and ancient Ayurvedic texts concluded that alcohol was a medicine if consumed in moderation but a poison if consumed in excess. Beer was known to Babylonians as early as 2700 BC.
Yeast can produce alcoholic beverages with up to 15 percent alcohol content. In order to produce a higher alcohol content, a process known as distillation is needed. Distilled spirits originated in China and India ca. 800 BC, but the distillation process became common in Europe only during the eleventh century and later. According to a survey by the U.S. government of adults ages eighteen and older, approximately 50 percent of adults are currently drinkers (at least twelve drinks in the past year) and 14 percent are infrequent drinkers (one to eleven drinks in the past year). In addition, 6 percent are former regular drinkers, 9 percent are former infrequent drinkers, while 21
percent are lifetime abstainers. Among current drinkers 61 percent are men and 42 percent are women.

 


According to a 2006 report by the National Institute of Alcohol Abuse and Alcoholism, each year approximately 5,000 young people under the age of twenty-one die as a result of underage drinking (approximately 1,900 deaths from motor vehicle accidents, 1,600 as a result of homicide, 300 from suicide, and others from injuries such as falls, burns, and drowning. Drug Use and Health Report published in November 2008, more than one-quarter of people ages twelve to twenty (28.1 percent) used alcohol in the past month, 51.1 percent of ages eighteen to twenty, 25.9 percent of ages fifteen to seventeen, and 6.1 percent of ages twelve to fourteen. This is a shocking statistic because alcohol has a devastating effect on the developing brain of a twelve-year-old person. Nearly one-third of the current underage alcohol drinkers (30.6 percent) paid for the last alcoholic drink they consumed, 14.6 percent got it free from another underage person, 8.5 percent received it from another relative, and an alarming 5.9 percent received their last drink from a parent or guardian. People who start drinking at an early age have a much greater risk of becoming alcohol dependent later in life than individuals who start drinking at age twenty-one or older. Alcohol can be considered a psychoactive drug because it has complex interactions with various neurotransmitters and receptors in the brain, producing pleasurable effects when consumed in moderation.

However, with excess consumption, the positive effects of drinking are replaced by negative effects, such as anxiety and depression. If consumed in moderation, alcohol can protect against age-related dementia and Alzheimer’s disease, but if consumed in excess it can cause severe brain damage. In addition, alcohol shares many pathways of various psychoactive drugs for its pharmacological actions. Alcohol, like any drug, has prophylactic effects in preventing many diseases, including coronary heart disease (the number one killer in America), stroke, various cancers, diabetes, arthritis, and other diseases, as well as increasing longevity (see chapter 4). However, if consumed in excess, it is detrimental to health (see chapter 5). Therefore, like a drug, alcohol is effective in low doses and toxic in higher doses.

Like a drug, alcohol is metabolized by liver enzymes, and a toxic metabolite of alcohol known as “acetaldehyde” is generated. If acetaldehyde is accumulated in the body due to excess alcohol intake, it can cause liver damage. Also, a man drinking the same amount of alcohol would have a lower peak blood alcohol level compared to a woman with the same body weight. This gender difference in the blood alcohol level is related to the different body water content between a man and a woman. Alcohol loves water and distributes into the aqueous part of the blood known as serum.

Because a woman has less body water content (52 percent on average) than a man (61 percent average), less water is available to dissolve the same amount of alcohol compared to a man. Some studies also report that women are more susceptible than men to alcohol-related impairment of cognitive functions.



Women also metabolize alcohol more slowly than do men because the concentration of alcohol dehydrogenase (ADH) is usually lower in women compared to men. Hormonal changes also play a role in the metabolism of alcohol in women, although this finding has been disputed in the medical literature. Some studies suggest that women metabolize alcohol at a higher rate during the luteal phase of the menstrual cycle (days 19–22 of the cycle), but a few days before menstruating, a woman’s alcohol metabolism may slow down. In general, a child will metabolize a drug faster than a younger or middle-aged adult, and an elderly person (older than sixty-five) will metabolize a drug more slowly than a younger or middle-aged adult. Metabolism of alcohol changes with advancing age because the activity of the enzymes involved in alcohol metabolism diminish with age. Water volume also reduces with advancing age. An elderly person would have a higher blood alcohol level from consumption of the same amount of alcohol compared to a younger person of the same gender.
The acetaldehyde produced due to the metabolism of alcohol, regardless of the pathway, is subsequently converted to acetate as a result of the action of mitochondrial aldehyde dehydrogenase (ALDH2). Acetaldehyde is fairly toxic compared to ethanol and must be metabolized quickly (equation 2.3).

Acetate or acetic acid then enters the citric acid cycle, which is a normal metabolic cycle of living cells, and is converted into carbon dioxide and water. From the chemical point of view, the body burns (oxidizes) alcohol into carbon dioxide and water, and this process generates calories.
Alcoholic beverages should not be consumed by some individuals, including those who cannot restrict their alcohol intake, women of childbearing age who may become pregnant, pregnant and lactating women, children and adolescents, individuals taking medications that can interact with alcohol, and those with specific medical conditions. Alcoholic beverages should be avoided by individuals engaging in activities that require attention, skill, or coordination, such as driving or operating machinery. Heavy consumption of alcohol leads not only to increased domestic violence, decreased productivity, increased risk of motor vehicle and job-related accidents, but also to increased mortality from liver cirrhosis, stroke, and cancer.
“Binge drinking” means heavy consumption of alcohol within a short period of time with the intention of becoming intoxicated. Although there is no universally accepted definition for binge drinking, usually consumption of five or more drinks by males and four or more drinks by females is considered binge drinking.
The two major alcohol-related brain disorders are alcoholic Korsakoff’s syndrome and alcoholic dementia. Korsakoff’s syndrome is a brain disorder caused by a deficiency of thiamine (vitamin B1), and major symptoms include severe memory loss, false memory, lack of insight, poor conversation skills, and apathy. Some heavy drinkers may also have a genetic predisposition to developing this syndrome.
In Korsakoff’s syndrome, loss of neurons is a common feature, including microbleeding in certain regions of gray matter.26 In an alcoholic, when Wernicke’s encephalopathy appears along with Korsakoff’s syndrome, it is called Wernicke-Korsakoff syndrome.

Wernicke’s encephalopathy and Korsakoff syndrome are two related diseases, both caused by thiamine deficiency, but accompanying clinical symptoms may be different. Alcoholics with Korsakoff syndrome always have severe amnesic syndrome (severe memory loss) but may not have classical symptoms of Wernicke’s encephalopathy, which include ophthalmoplegia (paralysis or severe weakness of one or more of the muscles that control eye movement), ataxia (lack of coordination during voluntary muscle movement, such as walking), and confusion. However, patients with Wernicke-Korsakoff syndrome show most of the symptoms found in both diseases. Alcoholics in general have a reduced brain weight compared to nondrinkers.
In a ten-year follow-up study in Sweden of 5,769 adults (ages
thirty-five to seventy-five) without cardiovascular disease, Foerster et al.
(2009) demonstrated that by increasing the amount of alcohol consumption
to more than twenty-five drinks per week, blood pressure increased
in heavy drinkers and all beneficial effects of alcohol consumption disappeared.
In addition, wine drinking increased good cholesterol (highdensity
lipoprotein cholesterol or HDL), while drinking beer and spirits
resulted in increased concentrations of triglycerides. U.S. physicians (2,970 diagnosed with diabetes mellitus), the authors
observed that weekly consumption of alcohol reduced the risk of heart
disease by 33 percent, while daily consumption of alcohol reduced the
risk by 58 percent among diabetics. For the nondiabetic, weekly consumption
of alcohol reduced the risk of heart disease by 18 percent, while daily
consumption of alcohol reduced the risk by 40 percent. The protective
effect of alcohol against stroke was detected in both younger and
older groups of men and women in all ethnic groups (white, black, and
Hispanic). However, this protective effect against stroke disappeared
in heavy drinkers (seven or more drinks per day), and such chronic
consumption of alcohol increased the risk of having strokes by approximately
three times that of nondrinkers.31 In a follow-up study, it was
demonstrated that moderate drinkers (up to two drinks per day) had a 33
percent reduced risk of ischemic stroke (all ethnic groups, both men and
women) compared to nondrinkers.
Moderate alcohol consumption can dramatically reduce the risk of age-related dementia and developing Alzheimer’s disease. A French study using 3,777 community residents ages sixty-five years or older demonstrated that the subjects who drank three to four glasses of alcoholic beverages (mostly wine) per day (318 subjects) had 82 percent lower risk of developing senile dementia and 75 percent lower risk of getting Alzheimer’s disease compared to nondrinkers (971 subjects). However, chronic abusers of alcohol are at a higher risk of developing memory loss, dementia, and lack of appropriate motor control due to alcohol-related brain damage. Younger people, especially underage drinkers, are also at higher risk of alcohol-related brain damage. In the California Men’s Health Study using 84,170

men ages forty-five to sixty-nine, consumption of one or more drinks per day was associated with approximately 60 percent reduced lung cancer.
Irregular heavy drinking even once a month (five or more drinks per occasion) increases the risk of heart disease rather than protecting the heart as observed in moderate drinkers. Binge drinking is also dangerous. In one study (based on a population of 1,641 men who drank beer), the authors observed that the risk of death in men who drank six or more bottles of beer in one occasion was almost three times higher than those who consumed less than three bottles in one occasion. Many investigators have reported a close link between violent behavior, homicide, and alcohol intoxication. Studies conducted on convicted murderers suggest that about half of them were under the heavy influence of alcohol at the time of the murder.
The liver is one of the largest and most complex organs of the human body. It synthesizes important proteins vital for life, stores some nutrients, and breaks down (metabolizes) drugs and toxins, including alcohol, thus protecting the body from harmful effects. Although the liver has an amazing capacity for self-healing through regeneration, certain liver diseases, such as cirrhosis of the liver, are irreversible and may even cause death. Alcohol-induced liver disease can be classified under three categories: (1) fatty liver; (2) alcoholic hepatitis; and (3) liver cirrhosis.

Heavy drinking for as little as a few days may produce fatty changes in the liver (steatosis), which can be reversed after abstinence. However, drinking heavily for a longer period may cause severer alcohol-related liver injuries, such as alcoholic hepatitis and cirrhosis of the liver. The diagnosis of alcoholic hepatitis is a serious medical condition because approximately 70 percent of such patients may progress to liver cirrhosis, a major cause of death worldwide. However, if a patient with alcoholic hepatitis practices complete abstinence, this condition may be reversible. Diminished sexual function in alcoholic men has been described for many years. Administration of alcohol in healthy young male volunteers causes diminished levels of testosterone. Even drinking three or more drinks a day may cause significant problems in women, including delayed ovula-tion or failure to ovulate and menstrual problems, but such problems do not affect women who consume two or fewer drinks a day. Approximately 2 to 4 percent of all cancer cases may be linked to alcohol abuse. Epidemiological research has demonstrated a dose-dependent relationship between consumption of alcohol and certain types of cancers; as alcohol consumption increases, so does the risk of cancer. The strongest link was found between alcohol abuse and cancer of the mouth, pharynx, larynx, and esophagus.