Zinc deficiency affects an estimated 17% of the global population, with mild-to-moderate deficiency more common than overt cases. In the US, deficiency is most often seen in vegetarians, older adults, people with malabsorption, and those on long-term diuretics. Symptoms can be subtle and develop gradually.
Common symptoms
Frequent infections, slow wound healing
Hair loss or thinning
Loss of taste or smell
Loss of appetite
Diarrhea (in severe cases)
Eye and skin lesions (in severe cases)
Delayed growth and development in children
Hypogonadism, impotence, or delayed puberty
Difficulty concentrating, mental fog
At-risk groups
Vegetarians and vegans (plant zinc has lower bioavailability due to phytates)
Older adults (a substantial share consume less zinc than recommended, and absorption declines with age)
Pregnant and breastfeeding women
Exclusively breastfed infants over 6 months without complementary feeding
People with GI conditions (Crohn's, ulcerative colitis, short bowel)
People with sickle cell disease
People with chronic kidney disease
People with alcohol use disorder
People taking long-term diuretics, ACE inhibitors, or penicillamine
When to see a doctorSlow wound healing that persists together with hair loss, frequent infections or loss of taste or smell is a reason to ask your doctor about a zinc test. Taking 50 mg of zinc or more a day for weeks can lower copper status, and the adult upper limit is 40 mg a day, so do not take high doses without medical advice.