Alcohol, Appetite, Digestion, Nausea, Diarrhea and Constipation

Alcohol and Appetite

In moderate drinkers, alcohol, when consumed within one hour before a meal, may stimulate appetite and therefore food and calorie intake ^[1,2].

Red wine may stimulate appetite more than beer, and beer more than a soft drink ^[3].

Substances other than ethanol in bitter aperitifs may stimulate appetite ^[30].

Poor appetite in chronic alcoholics may be due to depression, anxiety, nutrients deficiency (vitamins B1, B12, folate, magnesium), gastritis ^[4], alcoholic hepatitis ^[5], advanced liver cirrhosis ^[6] or cancer.

Alcohol and Digestion

Alcohol may slow down digestion, but does not necessary cause abdominal discomfort in healthy people. Alcohol can slow down gastric emptying ^[7,9]. In one 2008 study, 40 mL of various alcohol digestifs (40 vol% alcohol) drunk after a solid meal did not significantly stimulate or slow down gastric emptying, though ^[8].

Alcohol, Nausea and Vomiting

Different people may experience nausea or vomiting after drinking different amounts of alcohol. According to several blood alcohol concentration charts, a drinker may vomit when reaching blood alcohol concentrations between 0.12-0.25 g/100 mL blood or higher (for example, after 5-10 drinks or more in one hour by a 160 lbs man), depending on the drinking experience ^[10,11]. Repeated vomiting after drinking speaks for severe alcohol intoxication.

Causes of ACUTE nausea or vomiting related to alcohol:

• Stomach irritation
• Psychological aversion to alcohol
• Hypersensitivity or allergic reaction to ethanol, sulfites ^[13], histamine ^[12] or other substances in alcoholic beverages
• Deficiency of aldehyde dehydrogenase (ALDH2), a genetic disorder found mainly in the East Asians causing “Asian flush reaction” with facial flushing and nausea ^[14]
• Hangover ^[3]
• Alcohol withdrawal syndrome ^[15]
• Drinking alcohol during travel may aggravate symptoms of the motion sickness ^[17].
• Disulfiram (a drug to discourage drinking) may cause nausea within minutes of starting drinking ^[16].
• Combining alcohol with drugs, such as acid-lowering drugs (cimetidine), analgesics (phenacetin, phenylbutazone), antiasthmatics (albuterol, theophylline), antibiotics (cefamandole, chloramphenicol, griseofulvin, isoniazid, metronidazole, nitrofurantion, nitromidazole, sulfamethoxazole, tolbutamide), antifungals (ketokonazole), antidiabetics (chlorpropramide, tolbutamide), nitrates (isosorbide dinitrate, nitroglycerine) or chemotherapy.

Causes of PERSISTENT nausea or vomiting related to alcohol:

• Acute gastritis ^[15], or chronic atrophic gastritis due to H. pylori infection ^[18]
• Folate deficiency
• Magnesium deficiency
• Alcoholic ketoacidosis after exclusive alcohol drinking without eating (fruity breath odor) ^[19]
• Acute or chronic pancreatitis ^[43]
• Advanced liver cirrhosis ^[6]

Alcohol and Constipation

In individuals with irritable bowel syndrome (IBS), alcohol may trigger or aggravate constipation ^[20].

In the first days of alcohol abstinence after long-term drinking, constipation may develop, especially in depressed individuals ^[21].

In those who drink heavily for 10 or more years, a nerve damage called alcoholic neuropathy may result in constipation, numbness, “pins and needless” in hands and feet and muscle weakness, which may improve after stopping drinking and proper diet ^[22,23].

Alcohol and Diarrhea

Acute Diarrhea

• Even in healthy people, binge drinking may trigger diarrhea ^[24].
• Diarrhea may be one of the hangover symptoms ^[3].

Chronic Diarrhea

In individuals suffering from irritable bowel syndrome (IBS), drinking even moderate amount of alcohol, especially beer or red wine, may trigger diarrhea ^[20].

Chronic alcoholics may have diarrhea due to increased colon motility ^[25], lactose intolerance ^[26], poor diet resulting in a deficiency of folate, vitamin A, vitamin C or zinc, or damaged nerves (alcoholic polyneuropathy) ^[22]. All these conditions may improve after stopping drinking and proper diet.

In chronic drinkers with advanced chronic pancreatitis or liver cirrhosis, steathorrhea (fatty diarrhea with pale stools) may occur due to fat malabsorption.

In individuals with celiac disease, beer, barley malt beverages, wine coolers and certain liqueurs that contain gluten may trigger diarrhea ^[27]. Most ciders (not containing barley malt) and unflavored wines, sherry, mead, wine and fruit brandies, gin, martini, vermouth, whiskey, rum, tequila, ouzo, vodka and other unflavored spirits should be gluten-free ^[27].

In cancer patients on chemotherapy, alcohol may make diarrhea worse ^[28].

Lactose Intolerance

In individuals with lactose intolerance, certain beers, ciders, liqueurs and other sweetened alcoholic beverages that contain lactose may trigger diarrhea. Chronic alcohol drinking reduces the activity of the small intestinal enzyme lactase, which may result in lactose intolerance in black, but not white Americans ^[1,2,29].

Ethanol inhibits absorption of sodium and water in the small intestine what may result in diarrhea ^[3].

Alcohol and Obesity

Alcohol drinking by itself does not cause obesity; it is a total calorie excess that results in obesity. In general, regular moderate drinking does not seem to be associated with obesity ^[31].

Heavy drinking and binge drinking in drinkers who eat regularly often lead to obesity, but in drinkers who do not eat regularly, it may lead to malnutrition and weight loss.