Alcohol causes malnutrition and liver toxicity-Its Effects

alcohol consumption is a great contributor to malnutrition

Whichever way you look at it alcohol is the most abused drug and the most addictive of all known drugs in the world. The most surprising and interesting thing is that as toxic as it is, it is legalized and consumed freely. Its effect is felt in all homes directly and indirectly. Many alcoholics are malnourished, either because they ingest too little of essential nutrients like carbohydrates, proteins, and vitamins or because alcohol and its metabolism prevent their body from properly absorbing, digesting, and using those nutrients. As a result, alcoholics frequently experience deficiencies in proteins and vitamins, particularly vitamin A, which may contribute to liver disease and other serious alcohol–related disorders.

A complex interplay exists between a person’s alcohol consumption and nutritional status. Many people, including light to moderate drinkers who consume one to two glasses or less of an alcoholic beverage per day, consider those beverages a part of their normal diet and acquire a certain number of calories from them. When consumed in excess, however, alcohol can cause diseases by interfering with the nutritional status of the drinker. For example, alcohol can alter the intake, absorption into the body, and utilization of various nutrients. In addition, alcohol exerts some harmful effects through its breakdown (i.e., metabolism) and the resulting toxic compounds, particularly in the liver, where most of the alcohol metabolism occurs.

Alcohol causes malnutrition and liver toxicity-Nutritional Value of Alcohol

Alcoholic beverages primarily consist of water, pure alcohol (chemically known as ethanol), and variable amounts of sugars (i.e., carbohydrates); the content of other nutrients (e.g., proteins, vitamins, or minerals) is usually negligible. Because they provide almost no nutrients, alcoholic beverages are considered “empty calories.”) Therefore, any calories provided by alcoholic beverages are derived from the carbohydrates and alcohol they contain. The carbohydrate content varies greatly among beverage types.

At least under certain conditions, however, alcohol–derived calories when consumed in substantial amounts can have less biologic value than carbohydrate–derived calories, as shown in a study in the weights of two groups of participants who received balanced diets containing equal numbers of calories. In one of the groups, 50 percent of total calories were derived from carbohydrates, whereas in the other group the calories were derived from alcohol. The study participants were observed on the metabolic ward of a hospital during the experiments. The quantity of alcohol administered did not exceed the amount routinely consumed by these volunteers.

Although all participants received the same number of calories, those in the alcohol group exhibited a decline in body weight compared with those in the carbohydrate group. Moreover, when the participants received additional calories in the form of alcohol, they did not experience any corresponding weight gain. This suggests that some of the energy contained in alcohol is “lost” or “wasted” meaning, it is not available to the body for producing or maintaining body mass.

Alcohol causes malnutrition and liver toxicity-Nutritional Status

General observation suggests that many alcoholics do not consume a balanced diet; moreover, as mentioned earlier, excessive alcohol consumption may interfere with these alcoholics’ ability to absorb and use the nutrients they do consume. Accordingly, many alcoholics suffer from various degrees of both primary and secondary malnutrition. Primary malnutrition occurs when alcohol replaces other nutrients in the diet, resulting in overall reduced nutrient intake. Secondary malnutrition occurs when the drinker consumes adequate nutrients but alcohol interferes with the absorption of those nutrients from the intestine so they are not available to the body.

The most severe malnutrition, which is accompanied by a significant reduction in muscle mass, generally is found in those alcoholics who are hospitalized for medical complications of alcoholism (e.g., alcohol–related liver disease or other organ damage). If these patients continue to drink, they will lose additional weight; conversely, if they abstain from drinking, they will gain weight. This pattern applies to patients with and without liver disease.

Alcohol’s Effects on Digestion and Absorption of Essential Nutrients

Alcohol consumption, particularly at heavy drinking levels, not only influences the drinker’s diet but also affects the metabolism of those nutrients that are consumed. Thus, even if the drinker ingests sufficient proteins, fats, vitamins, and minerals, deficiencies may develop if those nutrients are not adequately absorbed from the gastrointestinal tract into the blood, are not broken down properly, and/or are not used effectively by the body’s cells. Two classes of nutrients for which such problems occur are proteins and vitamins.

Alcohol causes malnutrition and liver toxicity-Amino Acids and Proteins

Proteins are essential components of all cells. They help maintain the cell’s structure, transport certain substances in and out of cells, and act as enzymes that mediate almost all biochemical reactions occurring in the cells. Proteins are composed of approximately 20 different building blocks called amino acids. Many of these amino acids can be produced by the body itself from various precursors or are recycled when proteins that are damaged or are no longer needed are broken down or degraded. Other amino acids however, must be acquired through diet. Alcohol can interfere with the uptake of these essential amino acids.

Patients with chronic liver failure also exhibit a number of defects in protein metabolism. These include decreased production of proteins in the liver that are secreted into the blood decreased urea synthesis, and decreased metabolism of a group of amino acids called aromatic amino acids. These defects have important clinical consequences:

Alcohol causes malnutrition and liver toxicity-Vitamins

Vitamins are molecules that are present in small amounts in various foods and are essential for normal metabolism; insufficient vitamin levels in the body can lead to serious diseases. Alcoholics, even without liver disease, tend to have clinical and/or laboratory signs of deficiencies in certain vitamins, particularly vitamins B₁ (thiamine), B₂ (riboflavin), B₆ (pyridoxine), and C (ascorbic acid), as well as folic acid. The severity of these deficiencies correlates with the amount of alcohol consumed and with the corresponding decrease in vitamin intake.

A Person’s Nutrition Affects Liver Function

Malnutrition, regardless of its causes, can lead to liver damage and impaired liver function. For example, children in underdeveloped countries whose diets do not contain enough protein can develop a disease called kwashiorkor. One symptom of this disorder is the accumulation of fat in the liver, a condition known as fatty liver. Studies performed during and after World War II indicated that severe malnutrition also could lead to liver injury in adults. However, in these cases other factors, including exposure to certain toxins or parasites that are prevalent in war–ravaged or underdeveloped countries, may have exacerbated the relationship between liver injury and poor nutrition.

Because malnutrition also is common in alcoholics, clinicians initially thought that malnutrition, rather than alcohol itself, was responsible for alcohol–induced liver injury. Over the past 40 years, however, a more balanced view has evolved. Studies in humans, primates, and rodents have established that alcohol can cause liver damage even in well–nourished people.

It is becoming clear that nutritional effects and the toxic effects of alcohol often are intertwined at the biochemical level. For example, alcohol induces the MEOS to break down alcohol. Similarly, alcohol promotes the breakdown of nutrients such as vitamin A, of which alcoholics may already consume too little with their diet.

Alcohol causes malnutrition and liver toxicity-Its Effects