Alcohol's Effect on Nutrition

woman drinking alcohol

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Good nutrition is, of course, essential for providing energy and maintaining body structure and function. Many alcoholics, however, tend to eat less than the amount of food necessary to provide sufficient carbohydrates, protein, fat, vitamins, and minerals.

On top of that, alcohol itself can interfere with the nutrition process by affecting digestion, storage, utilization, and excretion of nutrients. Consequently, chronic heavy drinkers are hit with a double health whammy—they don't consume enough nutrients, and the nutrients they do consume are not utilized well.

As a result, many drinkers with alcohol use disorders are at least mildly malnourished and if their disorder is severe enough for them to be hospitalized, they are usually severely malnourished. Restored nutrition is one of the most important features of a 28-day inpatient program. Improving diet also helps brain function, which can be important for improving willpower needed for recovery.

How Nutrition Is Supposed to Work

The digestive system is supposed to work this way: The body begins to breakdown food into usable molecules in the mouth and continues the process in the stomach and intestines, with help from the pancreas.

Nutrients from digested food are absorbed into the blood from the intestines and carried to the liver where they are prepared for immediate use or for storage for later use.


Alcohol inhibits the natural breakdown of nutrients in several ways:

  • Decreasing secretion of digestive enzymes from the pancreas.
  • Impairing nutrient absorption by damaging the cells lining the stomach and intestines.
  • Disabling transport of some nutrients into the blood.
  • Preventing those nutrients that are absorbed from being fully utilized by altering their transport, storage, and excretion.
  • Alcohol also interferes with the body's microbiome.

If the person who is drinking to excess is also not eating well, their nutritional deficiencies alone can impair the absorption of nutrients by altering the cells lining the small intestine.

Energy Supply

Eating a balanced diet provides the body with the necessary calories to be used for energy, but some alcoholics will ingest a lot of their total daily calories from alcohol. As a result, fewer calories are obtained from nutritious food sources, which means that there will be fewer vitamins and minerals ingested.

Alcohol does provide calories, but the body processes and uses the energy from alcohol differently than it does the calories from food.


If alcohol is substituted for carbohydrates, calorie for calorie, the person will lose weight instead of gain weight. This means they are getting less energy from alcohol calories than from food calories.

In alcoholics who are malnourished, consuming alcohol can cause a decrease in blood sugar, which can cause serious injury. The hypoglycemia, even if short-lived, can cause the brain and other body tissue to be deprived of the glucose needed to function.

Maintenance of Function

Proteins, vitamins, and minerals are essential for maintaining proper body function. Alcohol can affect proper body functioning by causing nutrient deficiencies and by disrupting the "machinery" the body uses to metabolize nutrients.


Vitamins help regulate many physiological processes in the body essential to maintaining growth and normal metabolism. By impairing absorption, metabolism, and utilization of vitamins, chronic heavy drinking can cause vitamin deficiencies.

Alcohol consumption can cause deficiencies in vitamin A, C, D, E, K, and B vitamins.

These deficiencies can cause night blindness, softening of the bones, slow healing of wounds, decreased the ability of the blood to clot and, in the brain, severe neurological damage.


Alcoholics have been found to have deficiencies in calcium, magnesium, iron, and zinc. Research shows that drinking alcohol itself does not limit the absorption of minerals, but alcohol-related problems do. Mineral deficiencies may be caused by other alcohol-related conditions:

  • Decreased calcium absorption caused by fat malabsorption.
  • Magnesium deficiency due to poor diet.
  • Magnesium loss due to excretion, vomiting, and diarrhea.
  • Iron deficiency due to gastrointestinal bleeding.
  • Zinc losses related to other nutrient deficiencies.

Medical Complications

If you are drinking more than the recommended guidelines, chances are you are probably not eating as well as you should either. Here's an overview of how this can impact your nutrition and cause medical complications.

Liver Disease

Alcohol itself is the major cause of alcoholic liver disease, but poor nutrition can decrease nutrients normally found in the liver and therefore contribute to alcohol-related liver damage. Research has found that dietary fructose plus ethanol promotes liver inflammation.

Alcohol also depletes carotenoids, a major source of vitamin A and E in the liver.


Some studies have found that alcohol's damaging effect on the pancreas is exacerbated by a diet deficient in protein. Other research has suggested that malnutrition can increase the risk of developing alcoholic pancreatitis.

Brain Damage

Nutritional deficiencies can have a variety of severe and permanent effects on how the brain works. Thiamine deficiency in particular, which is frequently seen in people with severe alcohol use disorders, can cause serious neurological problems, impaired movement, and memory loss.

There is some indication that omega-3 fatty acid deficits may also influence brain function in people with alcohol use disorder.


Not only does drinking during pregnancy have direct toxic effects on fetal development, but alcohol-related nutritional deficiency can also affect the fetus, compounding the risk of developmental damage. Alcohol has been shown to restrict nutrition flow to the fetus.

Taking Care of Yourself

Excess alcohol in your system is potentially causing a variety of negative health effects on your body. Plus, you may also be facing a risk of damage from poor nutrition.

If you do drink, make sure that you look after yourself by getting enough nutrients, eating balanced meals, and maybe supplementing your diet with a good one-a-day multivitamin, appropriate for your age and gender. Good nutrition promotes good brain function, which can play a role in preventing alcohol misuse in the first place.

If you or a loved one are struggling with substance use or addiction, contact the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 1-800-662-4357 for information on support and treatment facilities in your area.

For more mental health resources, see our National Helpline Database.

12 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Buddy T
Buddy T is an anonymous writer and founding member of the Online Al-Anon Outreach Committee with decades of experience writing about alcoholism.