Does Alcohol Affect Bowel Movements?

How Does Alcohol Use Affect Bowel Movements?

Bowel movements occur when your digestive system has processed the food you have consumed and is ready to eliminate unnecessary waste products. While there is no strict definition of what constitutes a normal bowel movement, some parameters may help you understand which bowel movements are healthy and which are cause for concern.

People have between three bowel movements per day to three weekly, depending on what is typical for that individual. Stool should be soft – but formed – and certainly not painful to pass.

The Following Symptoms May Indicate a Digestive Problem:

• Excessive gas.
• Nausea and vomiting.
• Diarrhea or constipation.
• Abdominal pain.
• Bloating.
• Changes in stool color, such as black and tarry or pale and clay-like.
• Blood with bowel movements.

Alcohol disrupts normal bowel movements, especially when consumed in large quantities. Drinking alters your nutritional status, hydration, and even the physiological process behind digestion itself.

Faster Contractions of the Large Intestine

The large intestine – or colon – accounts for approximately 20% of the digestive tract. It is responsible for water, electrolyte, and vitamin absorption, as well as contractions to transport stool to the rectum for passage. After the small intestine extracts available nutrients from food, the remaining mass of waste moves to the colon for final processing.

Alcohol produces more frequent contractions in the large intestine. Stool does not have enough time to be processed by the colon, so less water and electrolytes are removed than usual. While the intestinal contraction speed increases, the ability of smooth muscle to form and compact stool decreases. This activity leads to abdominal cramping and diarrhea.

Impaired Nutrient Absorption

Drinking reduces pancreatic enzyme release necessary for proper digestion. Some vitamins pass through the GI tract without being fully extracted if these digestive molecules are insufficient. Alcohol also damages the lining of the stomach and intestines, so available nutrients are only partially absorbed. Rapid transit time through the large intestine also inhibits the colon’s ability to absorb vitamins as it would under normal conditions.

Individuals with alcohol use disorder (AUD) who binge drink or chronically consume alcohol are prone to nutrient deficiencies such as folate, B6, B12, thiamine, magnesium, phosphate, and vitamin A.

Irritable Bowel Syndrome (IBS)

Irritable Bowel Syndrome (IBS) is a disorder of the lower digestive tract. The cause is largely unknown but linked to certain foods and psychological conditions. IBS can be characterized by constipation (IBS-C), diarrhea (IBS-D), or mixed symptoms (IBS-M). Hallmarks of this condition include abdominal pain, gas, and bloating, all of which are relieved with a bowel movement. People with IBS frequently note changes in bowel movement frequency and stool consistency.

Individuals with IBS-D are more likely to have worsening symptoms after binge drinking than those with the mixed or constipated type. Symptoms are usually worst the day after drinking and resolve with alcohol abstinence and the return to normal eating and drinking habits.

Diarrhea and Dehydration

Alcohol’s effects on the colon and kidneys promote dehydration after binge drinking. Because the large intestine is responsible for absorbing water from stool before a bowel movement, faster contractions result in less fluid uptake. Likewise, alcohol acts as a diuretic, leading to rapid excretion of water and valuable electrolytes before they can be absorbed.  The combination of diarrhea and frequent urination quickly leads to dehydration and electrolyte imbalances necessary for proper brain and muscle functioning.

Internal Bleeding

Alcohol stimulates stomach acid production and reduces the protective gastric mucus layer, making stomach tissue susceptible to gastritis and ulcers. Such conditions may ultimately reach the blood vessels of the stomach, causing them to rupture and bleed. Meanwhile, the liver produces most coagulation factors necessary for proper blood clotting. Alcohol is broken down through the liver and alters the organ’s ability to metabolize other substances. Excessive drinking leads to liver inflammation and scarring, a condition known as cirrhosis. A cirrhotic liver cannot produce sufficient clotting factors, further increasing the risk of  GI bleeding.

Bowel movements are a critical factor in identifying internal bleeds. Blood from the lower digestive tract will be bright red. On the other hand, blood from the upper GI tract, such as that found in the stomach and small intestine, will be dark brown or black. This type of stool, called melena, has a tarry appearance and consistency. If you drink heavily and frequently, it is crucial to be aware of the color and texture of your bowel movements, as this sign may be the only indicator of an internal bleed.