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
Skin issues — acne, eczema, dry rough skin
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 (>60% may consume below the EAR)
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 doctorPersistent slow wound healing combined with hair loss, recurrent infections, or loss of taste/smell warrants a zinc test (serum or plasma zinc, ideally fasting). Important: long-term zinc supplementation above 40 mg/day can cause copper deficiency — don't supplement at high doses without medical guidance.