Alcohol has accompanied human civilization for thousands of years. It has been part of cultural rites, religious ceremonies, social gatherings, and family meals across many civilizations. However, long before the first brewery or vineyard existed, nature had already been producing it.
Wild yeast is one of nature’s most widespread microorganisms. It lives on the skins of fruits, flowers, leaves, tree bark, other plant surfaces, and in soil. It can also be carried through the air on dust particles and by insects. It is an ordinary part of the natural world, consuming sugars whenever they become available.
Throughout this article, the terms “alcohol” and “ethanol” are used interchangeably because ethanol is the specific alcohol found in alcoholic beverages. The alcohol found in beer, wine, and spirits is ethanol, a two-carbon alcohol produced when yeast ferments sugars.
Whenever yeast encounters sugar-rich fruits or plant sap under the right conditions, it ferments those sugars into ethanol and carbon dioxide. Alcohol is therefore not a product of plants or animals but primarily a metabolic byproduct of microorganisms. Humans eventually learned to harness this natural biological process to produce beer, wine, and other alcoholic beverages. This origin alone makes alcohol fundamentally different from staple foods.
Staple foods exist because they nourish the body. Grains, roots, legumes, fruits, vegetables, meat, fish, eggs, and dairy provide the energy and nutrients required for growth, maintenance, and repair. They supply essential amino acids, essential fatty acids, vitamins, minerals, and countless other compounds needed to sustain life. A person can live a healthy life without ever consuming alcohol. The same cannot be said for staple foods. This simple distinction explains why alcohol occupies such an unusual place in human nutrition.
Unlike vitamins or minerals, alcohol is not required by the body. Nor does it serve as a structural building block for muscles, cell membranes, or other body tissues. Ironically, alcohol is rarely thought of as a source of dietary energy because people do not consume it to satisfy hunger. Nevertheless, it contains considerable chemical energy, providing about seven calories per gram compared with about four calories per gram for carbohydrates and proteins. Although ethanol is only a two-carbon molecule, those carbon atoms contain sufficient chemical energy for the body to produce ATP.
If alcohol is not a staple food, why has red wine often been associated with antioxidant properties and potential health benefits? The answer lies not in the alcohol itself but in the grapes from which the wine is made. Alcohol is produced when yeast ferments the sugars naturally present in grapes, but the antioxidants often associated with red wine are not properties of the alcohol itself. They are naturally present in the grapes, particularly the skins and seeds, long before fermentation begins.
In other words, yeast produces ethanol, while grapes provide the polyphenols and other plant compounds. The antioxidants therefore come from the fruit, not the alcohol. This is why many of these beneficial compounds can also be obtained by eating grapes and other fruits without drinking alcohol.
Once alcohol enters the bloodstream, however, metabolism is concerned with the ethanol, not the grapes from which the wine was made. One unique property of alcohol is that it dissolves readily in both water and fats. It therefore spreads rapidly throughout the body. In other words, it moves easily through the water-based bloodstream and passes through the fatty membranes surrounding cells, allowing it to reach virtually every organ within minutes, including the brain.
Most people can easily recognize what happens next. Alcohol may initially make a person feel relaxed and more talkative. As more is consumed, reaction time slows, judgment becomes impaired, speech becomes slurred, and balance deteriorates. With excessive consumption, drowsiness and eventually unconsciousness may occur. These familiar effects begin because alcohol changes the way nerve cells communicate. It strengthens the signals that quiet the brain while weakening the signals that keep it alert and engaged, shifting the nervous system toward reduced activity.
At the same time, the liver begins metabolizing alcohol almost immediately. Ethanol is first converted into acetaldehyde, a highly reactive aldehyde, and then into acetate. The two-carbon acetate then enters the same energy-producing pathways used by carbohydrates and fats. This rapid processing is not because alcohol is the body’s preferred fuel. It is because alcohol and its reactive intermediate cannot safely be allowed to accumulate. A non-storable compound cannot linger in the body without increasing the likelihood of unwanted chemical reactions.
For this reason, alcohol moves to the front of the metabolic queue. While the body is busy clearing alcohol, the burning, or oxidation, of other fuels is temporarily reduced. Dietary fats and carbohydrates are not ignored, but they become more likely to be stored while alcohol receives metabolic priority. This is not because alcohol acts like insulin or instructs the body to store nutrients. Rather, its chemistry temporarily changes the order in which fuels are oxidized and handled by the body.
Therefore, alcohol is neither a conventional food nor an essential nutrient. It is a naturally occurring microbial fermentation product that happens to contain usable chemical energy. Its unique chemistry explains why the body extracts its energy while giving priority to its metabolism and removal, making alcohol fundamentally different from the staple foods that nourish and sustain human life.
Mukaila Kareem is a doctor of physiotherapy and founder of metabolichealthliteracy.com
