Alcohol and Coffee PDF

FOOD & HEALTH F24 / FDE428 Alcohol in the Body Dr. Ipek Bayram  Alcohol For chemists, alcohol refers to a class of organic compounds containing hydroxyl groups (e.g. glycerol) For most people, alcohol refers to the intoxicating ingredient in...

FOOD & HEALTH F24 / FDE428 Alcohol in the Body Dr. Ipek Bayram  Alcohol For chemists, alcohol refers to a class of organic compounds containing hydroxyl groups (e.g. glycerol) For most people, alcohol refers to the intoxicating ingredient in beer, wine, and liquor. The chemist’s name for this particular alcohol is ethyl alcohol, or ethanol. Alcohols act as lipid solvents. Their ability to dissolve lipids out of cell membranes allows alcohols to penetrate rapidly into cells, destroying cell structures and thereby killing the cells (mechanism of disinfectants). However, ethanol is less toxic than other alcohols. Sufficiently diluted and taken in small enough doses, it is tolerable by the body. Alcohol is a drug—that is, a substance that modifies body functions. Like all drugs, alcohol both offers benefits and poses hazards. The Dietary Guidelines for Americans advise “if alcohol it consumed, it should be consumed in moderation.”  How many drinks constitute moderate use, and how much is “a drink”? A “drink” is defined as: a) One glass of wine b) Two beers 1 oz ≈ 30 ml c) A drink with ½ ounce of pure ethanol d) One “shot” of 80 proof (40%) whiskey  Alcohol in the Body Moderation, moderation, moderation! ○ Potential health benefits: reduced risks for heart disease, diabetes, and osteoporosis ○ Potential health benefits for older adults: reduced mortality from all causes ○ Potential harm for younger adults (age 15-49): risk factor for premature death and disability MODERATION Since people have different tolerances for alcohol, it is impossible to name an exact daily amount of alcohol that is appropriate for everyone. Authorities have attempted to identify amounts that are acceptable for most healthy people. An accepted definition of moderation is up to two drinks per day for men and up to one drink per day for women. Notice that this advice is stated as a maximum not as an average; seven drinks one night a week would not be considered moderate, even though one a day would be. Doubtless, some people could consume slightly more; others could not handle nearly so much without risk. The amount a person can drink safely is highly individual, depending on genetics, health, gender, body composition, age, and family history. From the moment an alcoholic beverage enters the body, alcohol is treated as if it has special privileges. Its influence is most apparent in the GI tract, liver, and brain. In the GI Tract Unlike foods, which require When the stomach is full of food, alcohol time for digestion, alcohol has less chance of touching the walls needs no digestion and diffusing through, so its influence on the brain is slightly delayed. quickly absorbed across the walls of an empty stomach, Practical tip: eat snacks when reaching the brain within a drinking alcoholic beverages. few minutes. ✓ Carbohydrate snacks slow alcohol absorption and high-fat snacks slow peristalsis, keeping the alcohol in the Consequently, a person can stomach longer. immediately feel euphoric ✓ Salty snacks make a person thirsty; when drinking, especially on drink water instead of more alcohol. an empty stomach.  In the GI Tract The stomach starts to break down alcohol with its alcohol dehydrogenase enzyme. Women produce less of this enzyme than men; consequently, more alcohol reaches the intestine for absorption into the bloodstream. Therefore, women are more likely to become intoxicated. Such differences between men and women help explain why women have a lower alcohol tolerance and a lower guideline for moderate intake.  In the GI Tract ▪ In the small intestine, alcohol is rapidly absorbed. ▪ From this point on, alcohol receives priority treatment: it gets absorbed and metabolized before most nutrients. ▪ Alcohol’s priority status helps ensure a speedy disposal and reflects two facts: 1. alcohol cannot be stored in the body. 2. it is potentially toxic. In the Liver Liver cells are the first to receive alcohol-laden blood. Liver cells are the only cells in the body that can make enough of the alcohol dehydrogenase enzyme to oxidize alcohol at an appreciable rate. The routing of blood through the liver cells gives them the chance to dispose of some alcohol before it moves on. Alcohol disrupts liver activity  For example, liver cells normally prefer fatty acids as their fuel, and they like to package excess fatty acids into triglycerides and ship them out to other tissues. When alcohol is present, however, the liver cells metabolize alcohol first and let the fatty acids accumulate. Alcohol metabolism can also permanently change liver cell structure, impairing the liver’s ability to metabolize fats. As a result, heavy drinkers develop fatty livers. If liver cells could talk, they would describe alcohol as demanding, egocentric, and disruptive of the liver’s efficient way of running its business Liver & Alcohol Metabolism The liver is the primary site of alcohol metabolism. It can process about ½ ounce of ethanol per hour (the amount defined as a drink), depending on the person’s body size, pervious drinking experience, food intake, and general health. This maximum rate of alcohol breakdown is determined by the amount of alcohol dehydrogenase available. If more alcohol arrives at the liver than the enzymes can handle, the extra alcohol travels around the body, circulating again and again until liver enzymes are finally available to process it. Another practical tip: drink slowly enough to allow the liver to keep up-no more than one drink per hour. Liver & Alcohol Metabolism The amount of alcohol dehydrogenase enzyme present in the liver varies with individuals, depending on the genes they have inherited and on how recently they have eaten. Fasting for as little as a day prompts the body to degrade its proteins, including the alcohol-processing enzymes, and this can slow the rate of alcohol metabolism by half. Drinking after not eating all day thus causes the drinker to feel the effects more promptly for two reasons: 1. rapid absorption and 2. slow breakdown Alcohol Metabolism Alcohol dehydrogenase oxidizes alcohol to acetaldehyde— a highly reactive and toxic compound. High concentrations of acetaldehyde in the brain and other tissues are responsible for many of the damaging effects of alcohol. Acetaldehyde dehydrogenase converts acetaldehyde to acetate, which is then converted to acetyl CoA—the compound that plays a role in energy metabolism. The reactions from alcohol to acetaldehyde to acetate produce hydrogens and electrons. The B vitamin niacin, in its role as a coenzyme, picks up these hydrogens and electrons. Alcohol Metabolism During alcohol metabolism, the multitude of other metabolic processes for which the niacin coenzyme is required, including glycolysis, the TCA cycle, and the electron transport chain, falter. Its presence is sorely missed in these energy pathways because it is the chief carrier of the hydrogens that travel with their electrons along the electron transport chain. Without adequate coenzymes, these energy pathways cannot function. Excess acetyl CoA then takes the pathway to fatty acid synthesis. Effects on the Liver The synthesis of fatty acids accelerates with exposure to alcohol. Fatty liver, the first stage of liver deterioration seen in heavy drinkers, interferes with the distribution of nutrients and oxygen to the liver cells. Fatty liver is reversible with abstinence from alcohol. If fatty liver lasts long enough, however, the liver cells will die and form fibrous scar tissue. This second stage of liver deterioration is called fibrosis. Some liver cells can regenerate with good nutrition and abstinence from alcohol, but in the most advanced stage, cirrhosis, damage is the least reversible. Alcohol Metabolism The liver’s priority treatment of alcohol affects its handling of drugs as well as nutrients. In addition to the dehydrogenase enzymes, the liver possesses an enzyme system that metabolizes both alcohol and several other types of drugs. Called the MEOS (microsomal ethanol-oxidizing system), this system handles about one-fifth of the total alcohol a person consumes. At high blood concentrations or with repeated exposures, alcohol stimulates the synthesis of enzymes in the MEOS. The result is a more efficient metabolism of alcohol and tolerance to its effects. As a person’s blood alcohol rises, alcohol competes with-and wins out over- other drugs whose metabolism also relies on the MEOS. Alcohol Metabolism ▪ If a person drinks and uses another drug at the same time, the MEOS will dispose of alcohol first and metabolize the drug more slowly. While the drug waits to be handled later, the dose may build up so that its effects are greatly amplified-sometimes to the point of being fatal. ▪ Many drug labels provide warnings to avoid alcohol while taking the drug. ▪ In contrast, once a heavy drinker stops drinking and alcohol is no longer competing with other drugs, the enhanced MEOS metabolizes drugs much faster than before. As a result, determining the correct dosages of medications can be challenging.  Alcohol Disposal Although the major way that the blood is cleared of alcohol is metabolism by the liver, but there is another way. About 10% of the alcohol leaves the body through the breath and in the urine. This is the basis for the breath and urine tests to determine blood alcohol concentrations. The amounts of alcohol in the breath and in the urine are in proportion to the amount in the bloodstream and brain. In all states, legal drunkenness is set at 0.08 percent or less, reflecting the relationship between alcohol use and traffic and other accidents. Effects on the Brain Alcohol is a narcotic. People used it for centuries as an anesthetic because it can deaden pain. o But alcohol was a poor anesthetic because one could never be sure how much a person would need and how much would be a fatal dose. Today’s anesthetics provide a more predictable response. Alcohol continues to be used socially to help people relax or to relieve anxiety. People think that alcohol is stimulant because it seems to relieve inhibitions. o Actually, though, it accomplishes this by sedating the inhibitory nerves, which are more numerous than excitatory nerves. Ultimately, alcohol acts as a depressant and affects all the nerve cells. Effects on the Brain Alcohol Blood Levels and Brain Responses  Alcohol Blood Levels and Brain Responses Blood Alcohol Typical Effects Concentration (%).02 Loss of judgment, altered mood.05 Exaggerated behavior, loss of small muscle control, impaired judgment, lowered alertness.08 Poor muscle coordination; impaired selfcontrol, reasoning, and memory.10 Deterioration of reaction time and control, slurred speech, poor coordination, slowed thinking.15 Minimal muscle control, loss of balance.20 Confusion, disorientation, possible blackouts.30 Stupor, minimal comprehension.40 Lethal dose (heart beat and respiration slow down dramatically and may stop) NOTE: Blood alcohol concentration depends on a number of factors, including alcohol in the beverage, the rate of consumption, the person's gender, and body weight. For example, a 100-pound female can become legally drunk (≥=0.10 concentration) by drinking three beers in an hour, whereas a 220-pound male consuming that amount at the same rate would have a 0.05 blood alcohol concentration. Like liver cells, brain cells die with excessive exposure to alcohol. Liver cells may be replaced, but not all brain cells can regenerate. Thus, some heavy drinkers suffer permanent brain damage. Dehydration People who drink alcoholic beverages may notice that they urinate more, but they may be unaware of the vicious cycle that results. Alcohol depresses production of antidiuretic hormone (ADH), a hormone produced by the pituitary gland that retains water -consequently, with less ADH, more water is lost. Loss of body water leads to thirst; and thirst leads to more drinking. Water will relieve dehydration, but the thirsty drinker may drink alcohol instead, which only worsens the problem. Practical tip: Drink water when thirsty and before each alcoholic drink. Drink an extra glass or two before going to bed. This strategy will help lessen the effects of hangover. Malnutrition / Weight Contributes to body fat and weight gain ○ Leads to central obesity (“beer belly”) Alcohol often replaces a meal in heavy-drinkers! Substitution leads to: ○ Malnutrition ○ 7 kcal/gram of energy, but empty of nutrients Nutrient displacement ○ B vitamins Effect of Alcohol on Nutrient Metabolism Chronic alcohol abuse not only displaces nutrients from the diet, but it also interferes with the body’s metabolism of nutrients. Most dramatic is alcohol’s effect on the B vitamin folate (B9). The liver loses its ability to retain folate, and the kidneys increase their excretion of it. Alcohol abuse creates a folate deficiency that devastates digestive system function. The small intestine normally releases and retrieves folate continuously, but it becomes damaged by folate deficiency and alcohol toxicity, so it fails to retrieve its own folate and misses any available from food as well. Effect of Alcohol on Nutrient Metabolism Alcohol also interferes with the action of folate in converting the amino acid homocysteine to methionine. The result is an excess of homocysteine, which has been linked to heart disease, and an inadequate supply of methionine, which slows the production of new cells, especially the rapidly dividing cells of the intestine and the blood. The combination of poor folate status and alcohol consumption has also been implicated in promoting colorectal cancer. Effect of Alcohol on Nutrient Metabolism The inadequate food intake and impaired nutrient absorption that accompany chronic alcohol abuse frequently leads to a deficiency of another B vitamin- thiamin (B1). ▪ The cluster of thiamin-deficiency symptoms commonly seen in chronic alcoholism has its own name-Wernicke-Korsakoff Syndrome. ▪ This syndrome is characterized by paralysis of the eye muscles, poor muscle coordination, impaired memory, and damaged nerves. Malnutrition occurs not only because of lack of intake and altered metabolism but also because of direct toxic effects as well. ▪ Alcohol causes stomach cells to oversecrete both gastric acid and histamine, an immune system agent that produces inflammation. ▪ Beer in particular, stimulates gastric acid secretion, irritating the linings of the stomach and esophagus and making them vulnerable to ulcer formation. Signs of Alcoholism Tolerance: the person needs higher and higher intakes of alcohol to achieve intoxication. Withdrawal: the person who stops drinking experiences anxiety, agitation, increased blood pressure, or seizures, or seeks alcohol to relieve these symptoms. Impaired control: the person intends to have 1 or 2 drinks, but has many more instead, or the person tries to control or quit drinking, but efforts are unsuccessful. Disinterest: the person neglects important social, family, job, or school activities because of drinking. Time: the person spends a great deal of time obtaining and drinking alcohol or recovering from excessive drinking. Signs of Alcoholism Cravings: the person has strong urges to use alcohol. Impaired ability: the person’s intoxication or withdrawal symptoms interfere with work, school, or home. Problems: the person continues drinking despite physical hazards or medical, legal, psychological, family, employment, or school problems caused or exacerbated by alcohol. These conditions suggest that a person may have an alcohol problem and might benefit from an abstinence program or professional help. Source: Adapted from Diagnostic and Statistical Manual of Mental Disorders, 5th ed. (Washington, D.C.: American Psychiatric Association, 2013). FOOD & HEALTH F24 / FDE428 Coffee in the Body Dr. Ipek Bayram  Coffee 1200 years Originated in northeast Africa, spread out to the Middle East in the 15th century and then to Europe The second most valuable commodity around the world (after oil). Today, coffee is the most widely consumed pharmacologically active beverage. ○ The average consumption for a person in the European Community is 5.1 kg/year, which is similar to that in the United States. Coffee is a driving force for humans to develop science, because it has an alerting effect on the human brain. However, some people report experiencing irregular heartbeat or headaches, which suggests individual variation to coffee intolerance.  Coffee Coffee is a complex mixture of chemicals and is the main source of caffeine in many populations. However, it also contains thousands of different chemicals, including carbohydrates, lipids, nitrogenous compounds, vitamins, minerals, alkaloids, and phenolic compounds.  Coffee Although caffeine is a major component of coffee, the content is highly variable—ranging between 30 mg and 175 mg in a cup (150 mL) of home-prepared coffee. Caffeine is the most widely consumed psychoactive drug worldwide and appears to exert most of its biological effects through the antagonism of the adenosine receptor. Adenosine is an inhibitory neuromodulator that increases the feeling of drowsiness, and thus caffeine induces generally stimulatory effects in the central nervous system.  Coffee Coffee is the number one diet source of antioxidants in many countries. ○ Coffee beans contain phenolic antioxidants! The major polyphenol in coffee is chlorogenic acid. The antioxidant activity of coffee depends on the chemical composition. The antioxidant activity of coffee also varies according to the degree of roasting. Maximum antioxidant activity was measured for the medium-roasted coffee. Myth: Coffee consumption has been associated with higher concentrations of serum total cholesterol and LDL cholesterol. Cafestol and kahwoel are two diterpenes found in coffee oil. Diterpenes are the main cholesterol-raising compounds in coffee, but they are mostly removed by paper filters. Therefore, unfiltered coffee is a significant source of diterpenes, whereas the consumption of filtered coffee results in very little increase in serum cholesterol.  Health Effects of Coffee The relationship of coffee with health has been featured in more than 8000 professional medical studies during the past 40 years. However, in many cases, conflicting findings and concerns have arisen, making it difficult for health professionals and the public to interpret the data. Challenges: ○ Coffee consumption tends to attract tobacco smoking, but many studies did not account for this potential confounding the data analysis. ○ Some measurement errors seem to be inevitable in the assessment of coffee consumption, because people consume a wide variety of coffee from day to day. ○ Coffee intake is determined by the size of the coffee cup and the strength of the brew as well as frequency of consumption. However, most studies concluded that coffee is a safe beverage that may even offer some health benefits when consumed in moderation!  Positive Health Effects of Coffee Many studies show that coffee consumption may help prevent several chronic diseases. ○ long-term coffee consumption is associated with significant dose-dependent reductions in the risk of developing type 2 diabetes. ○ coffee intake reduces the risk of liver damage in people at high risk for liver disease including hepatic injury, cirrhosis, and hepatocellular carcinoma. ○ coffee intake reduces the risk of Parkinson's disease in men and women. ○ risk of Alzheimer's disease is also lower in those who regularly consume caffeine-containing coffee than in those who do not drink it. ○ coffee improves endurance performance in long-duration physical activities. ○ coffee consumption has been inversely associated with the risk of cancer at various sites including liver and colon, but there is no clear explanation of how coffee protects against cancer.  Negative Health Effects of Coffee Coffee might have modest cardiovascular effects such as tachycardia, arrhythmia, and high blood pressure (hypertension). ○ No definite clinical relationship between coffee intake and the risk of cardiac tachycardia and arrhythmia, many doctors would not recommend coffee for the patients. ○ Any contribution of coffee ingestion to the development of hypertension is likely to be small, but it is considerable particularly in infrequent coffee drinkers. Caffeine leads to a slight decrease in the efficiency of calcium absorption in gastrointestinal tract. Thus, an adequate intake of calcium and vitamin D and a limitation of coffee intake to 2–3 cups/day may help reduce the risk of osteoporosis and its related fracture particularly in elderly adults. Caffeine crosses the human placenta thus excessive intake of caffeine has been implicated as a cause of spontaneous abortion or impaired fetal growth. Caffeine intake for women who plan to become or is pregnant should not exceed 300 mg/day. Caffeine consumption in children might alter behavior including nervousness and anxiety. It is judged that an intake of 2.5 mg/kg body weight/day is an upper limit of caffeine consumption in children.