Alcohol depletes a wide range of vitamins and minerals, with B vitamins hit the hardest. Heavy or chronic drinking interferes with nutrient absorption in the gut, accelerates the breakdown of vitamins already in your body, and increases how quickly your kidneys flush them out. The result is a pattern of overlapping deficiencies that can affect everything from energy levels to brain function.
Thiamine (Vitamin B1)
Thiamine is the nutrient most dangerously affected by alcohol. Your body absorbs thiamine through specialized transporters in the gut lining, and chronic alcohol use directly suppresses the genes that produce these transporters. With fewer transporters available, less thiamine makes it from your food into your bloodstream, even if your diet is otherwise adequate.
Thiamine is essential for converting food into energy and for maintaining healthy nerve tissue. When levels drop low enough, the consequences can be severe. Wernicke-Korsakoff syndrome, a two-stage brain disorder involving confusion, loss of coordination, and permanent memory damage, is caused specifically by thiamine deficiency in people who drink heavily. The early stage (Wernicke’s encephalopathy) is a medical emergency that can be reversed with high-dose thiamine, but the later stage (Korsakoff’s psychosis) often causes lasting cognitive impairment.
The Royal College of Physicians in London recommends oral thiamine (100 mg three times daily) for at-risk individuals who don’t yet show symptoms, while those with confusion or coordination problems typically need thiamine given directly into the bloodstream because oral doses may not raise blood levels fast enough. A 2013 Cochrane Review found that the clinical evidence is still insufficient to pin down the ideal dose and duration, which means treatment protocols vary between hospitals.
Folate (Vitamin B9)
Folate levels drop quickly when you drink. In clinical studies, serum folate fell within eight hours of alcohol exposure, whether the alcohol was taken by mouth or given intravenously. That rapid drop happens because alcohol disrupts the recycling loop your body uses to reclaim folate from bile and reabsorb it in the intestine.
Chronic drinking causes deeper damage. Studies on long-term drinkers show reduced expression of the proteins responsible for transporting folate across the intestinal wall. That means even when folate is present in food, less of it gets absorbed. Folate is critical for DNA repair and red blood cell production, so deficiency can lead to a type of anemia where red blood cells become abnormally large and inefficient at carrying oxygen. Low folate also raises levels of homocysteine, an amino acid linked to cardiovascular risk.
Vitamin B6
Alcohol’s effect on B6 is unusually direct. When your liver processes alcohol, it produces acetaldehyde, a toxic byproduct. Acetaldehyde accelerates the breakdown of pyridoxal phosphate, the active form of B6 that your cells actually use. Research published in The Journal of Clinical Investigation showed that acetaldehyde activates a specific enzyme (a phosphatase) that strips the phosphate group off B6 compounds in red blood cells, effectively destroying them.
This means even if you’re eating enough B6-rich foods like poultry, fish, and potatoes, your body breaks down the vitamin faster than you can replace it. B6 is involved in over 100 enzyme reactions, including the production of neurotransmitters like serotonin and dopamine. Deficiency can show up as irritability, depression, confusion, and a weakened immune response.
Vitamin B12
B12 and folate are biochemically intertwined. B12 serves as a cofactor in the reaction that converts folate into its usable form, and that same reaction produces methionine, an amino acid your body needs for countless processes. When alcohol disrupts folate metabolism, B12 gets pulled into the dysfunction. Chronic drinkers frequently have low B12 levels, which compounds the neurological symptoms already caused by thiamine and B6 deficiency. Tingling in the hands and feet, difficulty with balance, and memory problems can all stem from B12 depletion.
Vitamin A
Your liver stores the vast majority of your body’s vitamin A, packed away inside specialized cells called stellate cells. Chronic alcohol consumption depletes these stores through a two-phase process: first, alcohol triggers the release of stored vitamin A into the bloodstream (mobilization), and then it ramps up the activity of liver enzymes that break vitamin A down into inactive compounds (catabolism).
What makes this particularly concerning is that the depletion happens regardless of how much vitamin A you eat. Animal studies using carefully controlled diets confirmed that alcohol-induced vitamin A loss is independent of dietary intake or absorption problems. The liver simply destroys its own reserves faster. Vitamin A is essential for immune function, vision (especially night vision), and skin integrity. However, supplementing vitamin A during heavy drinking carries its own risks, because both alcohol and high-dose vitamin A are toxic to the liver, and combining them can accelerate liver damage.
Vitamin C
Alcohol increases the rate at which your kidneys excrete vitamin C. Research found that alcohol consumption produced a 47% increase in urinary vitamin C excretion, meaning nearly half again as much vitamin C was being flushed out compared to baseline. Over time, this accelerated loss contributes to deficiency, especially in heavy drinkers whose diets are often low in fruits and vegetables to begin with.
Vitamin C is one of the body’s primary antioxidants, and alcohol generates significant oxidative stress as the liver metabolizes it. So at the very moment your body needs more antioxidant protection, it’s losing the raw materials faster. Low vitamin C impairs wound healing, weakens blood vessel walls (leading to easy bruising), and reduces immune function.
Magnesium and Zinc
Alcohol doesn’t just deplete vitamins. Two minerals are commonly affected as well. Magnesium is lost through increased urinary excretion during and after drinking. Since magnesium plays a role in muscle relaxation, nerve signaling, and sleep regulation, deficiency can contribute to muscle cramps, anxiety, insomnia, and irregular heartbeat, symptoms that overlap with and worsen alcohol withdrawal.
Zinc depletion follows a similar pattern. Heavy drinkers lose zinc through both urine and the intestinal tract. Alcohol also lowers serum albumin, the protein that carries zinc through the bloodstream, reducing how efficiently the body can distribute whatever zinc remains. Even a single session of moderate drinking has been shown to increase zinc, iron, and aluminum loss through the kidneys and gut. Zinc deficiency impairs taste and smell, slows wound healing, and weakens immune defenses.
Why the Damage Stacks Up
What makes alcohol’s nutritional impact so damaging is that it attacks from multiple angles simultaneously. It reduces absorption in the gut, accelerates breakdown in the liver and blood, increases excretion through the kidneys, and often coincides with a poor diet that fails to replace what’s lost. Many of these nutrients also depend on each other: B12 needs folate to function, B6 is required to convert stored forms of other vitamins into active ones, and magnesium is involved in hundreds of enzymatic reactions that process other nutrients.
The severity of depletion depends on how much and how long you drink. Occasional moderate drinking is unlikely to cause clinically significant deficiency in someone eating a balanced diet. But regular heavy drinking, even over weeks rather than years, can create measurable drops in thiamine, folate, and magnesium. For people in recovery, targeted supplementation with a B-complex vitamin, vitamin C, magnesium, and zinc can help restore what’s been lost, though the timeline for recovery varies depending on how depleted stores have become and whether any organ damage has occurred.