Zinc deficiency happens when your body consistently gets too little zinc from food, absorbs it poorly, or loses too much of it. An estimated 17.3% of the global population is at risk of inadequate zinc intake, with rates ranging from about 7.5% in high-income countries to 30% in South Asia. The causes fall into a few broad categories: diet, digestive conditions, chronic diseases, alcohol use, medications, and rare genetic disorders.
Diet Is the Most Common Cause
The single biggest driver of zinc deficiency worldwide is not eating enough zinc-rich food, or eating zinc in forms your body can’t easily use. Meat, shellfish, and dairy are the richest sources of highly absorbable zinc. Beans, nuts, and whole grains contain zinc too, but your body absorbs far less of it from these foods.
The reason comes down to a compound called phytate, which is the way plants store phosphorus. Phytate binds to zinc in your intestine and forms an insoluble complex that passes right through you. Depending on how much plant-based food is in a meal, the percentage of zinc your body actually absorbs can range from as low as 5% to more than 50%. A meal built entirely around animal foods delivers the most zinc; a mixed meal delivers less; and a fully plant-based meal delivers the least.
This is why people following vegetarian or vegan diets are at higher risk. They tend to eat large amounts of legumes and whole grains (high in phytate) while skipping the most bioavailable source (meat). Studies consistently show that vegetarians and vegans have both lower zinc intake and lower blood zinc levels than people who eat animal products. That doesn’t mean plant-based diets inevitably cause deficiency, but they do require more deliberate planning.
Digestive Diseases That Block Absorption
Even if you eat plenty of zinc, certain gastrointestinal conditions can prevent your intestines from absorbing it properly. Crohn’s disease is one of the best-documented examples. Zinc deficiency is well established in Crohn’s patients, partly because the small intestine absorbs zinc poorly even when it appears structurally normal, and partly because dietary restrictions common in Crohn’s management limit zinc-rich foods.
Celiac disease also reduces zinc absorption, since the damage to the intestinal lining impairs the gut’s ability to take in nutrients across the board. Inflammatory bowel diseases more broadly create a cycle: the inflammation itself generates malabsorption, which leads to zinc depletion, which can in turn worsen gut health. Other conditions that shorten or damage the intestinal tract, like short bowel syndrome or chronic diarrhea, have similar effects.
Chronic Kidney Disease
People with chronic kidney disease (CKD) face a unique combination of factors that drain zinc from the body. The list includes dietary protein restrictions (which cut out zinc-rich foods), reduced calorie intake, intestinal malabsorption, and, critically, a phenomenon called urinary zinc wasting. As kidney function declines, the kidneys lose their ability to reabsorb zinc, so more of it spills into the urine. One cohort study found that CKD patients excreted roughly 28% more zinc in their urine per day than people without kidney disease, and their plasma zinc levels were correspondingly lower.
This isn’t limited to late-stage kidney failure. Abnormalities in zinc metabolism develop before kidneys reach the point of needing dialysis. Dialysis itself can further deplete zinc, but the problem starts earlier. In one case-control study, patients on maintenance dialysis had average serum zinc levels of about 69 mcg/dL compared to 83 mcg/dL in healthy controls.
Alcohol Use
Chronic alcohol consumption hits zinc levels from two directions at once: it increases how much zinc you excrete in urine and decreases how much you absorb from food. The consequences go beyond simple depletion. Zinc is essential for the enzyme your liver uses to break down alcohol. When zinc levels drop, the liver shifts to an alternative metabolic pathway that generates more harmful free radicals, accelerating liver damage. This creates a vicious cycle where drinking causes zinc loss, and zinc loss makes alcohol more toxic to the liver.
Pregnancy and Breastfeeding
Zinc requirements increase by roughly 18 to 36% during pregnancy to support both the mother’s physiological changes and fetal development. The recommended daily intake during pregnancy is 7 to 15 mg, depending on the country’s guidelines. During breastfeeding, demands remain elevated because human milk is a newborn’s primary source of zinc. Infants need 2 to 4 mg per day in the first six months and 3 to 5 mg per day from seven to twelve months, all supplied through breast milk. If a mother’s diet doesn’t keep pace with these increased needs, her own zinc stores can become depleted.
A Rare Genetic Cause
Acrodermatitis enteropathica is a rare inherited disorder that makes the body unable to absorb zinc normally. It’s caused by mutations in a gene called ZIP4, which codes for a zinc transporter protein in the intestinal lining. Some mutations completely knock out the transporter’s function by trapping it inside cells before it can reach the surface. Others partially reduce its activity. Either way, the result is severe zinc deficiency from infancy, with symptoms like skin rashes, diarrhea, and hair loss appearing shortly after weaning. The condition is recessive, meaning a child must inherit a defective copy from both parents. Without lifelong zinc supplementation, it can be fatal.
Medications That Deplete Zinc
Certain widely prescribed medications can lower zinc levels over time. Diuretics (commonly used for blood pressure) increase urinary zinc excretion. Some antibiotics and acid-reducing medications can interfere with zinc absorption in the gut. If you take any of these long-term, your zinc status may gradually decline without obvious warning signs, especially if your dietary intake is already borderline.
Why Multiple Causes Often Overlap
In practice, zinc deficiency rarely has a single neat explanation. A person with Crohn’s disease may also be avoiding meat because it triggers symptoms. Someone with kidney disease is often on multiple medications and a restricted diet. A pregnant woman who follows a vegan diet faces both increased requirements and lower absorption. The compounding effect of two or three risk factors together is what typically pushes someone from adequate zinc status into genuine deficiency. Recognizing which factors apply to you is the first step toward knowing whether your zinc intake actually matches your body’s needs.