Zinc Blood Test: Normal Ranges, Causes & What Your Results Mean

What Is Zinc?

Zinc is an essential trace mineral involved in over 300 enzymatic reactions in the body. It plays critical roles in immune function, wound healing, DNA synthesis, protein production, cell division, and the senses of taste and smell. Zinc is also vital for growth and development during pregnancy, childhood, and adolescence.

The body has no specialised zinc storage system, so regular dietary intake is essential. Approximately 60% of body zinc is found in skeletal muscle, 30% in bone, and the remainder in skin, liver, brain, and other tissues. Serum zinc represents only about 0.1% of total body zinc, making blood levels a somewhat imprecise marker — but it remains the most practical clinical test available.

Why Is Zinc Tested?

• Investigate symptoms of zinc deficiency: impaired wound healing, frequent infections, hair loss, skin lesions, or altered taste
• Assess nutritional status in patients with restricted diets, malabsorption, or chronic illness
• Evaluate patients with chronic diarrhoea, inflammatory bowel disease, or liver cirrhosis
• Monitor zinc status in vegetarians and vegans — plant-based diets contain phytates that reduce zinc absorption
• Investigate unexplained growth faltering in children
• Assess patients with recurrent infections or poor immune function
• Monitor patients on long-term zinc supplementation to avoid excess

Normal Ranges

Zinc levels vary with time of day and fasting status. Morning fasting samples are most reliable. Levels also drop during acute infection and inflammation (zinc redistributes to the liver).

Causes of Low Zinc

• Inadequate dietary intake: Diets low in meat, shellfish, and legumes
• Vegetarian/vegan diets: Phytates in grains, legumes, and seeds bind zinc and reduce absorption by up to 50%
• Malabsorption: Coeliac disease, Crohn's disease, short bowel syndrome, or chronic diarrhoea
• Liver disease: Cirrhosis impairs zinc metabolism and increases urinary losses
• Chronic kidney disease: Dialysis removes zinc; medications may impair absorption
• Alcohol use: Alcohol reduces zinc absorption and increases urinary excretion
• Medications: Proton pump inhibitors, diuretics, penicillamine, and some antibiotics
• Pregnancy and lactation: Increased demand can deplete maternal stores
• Acrodermatitis enteropathica: A rare genetic condition causing severe zinc malabsorption
• Acute illness/inflammation: Zinc levels drop during infection as the liver sequesters zinc — this is a temporary redistribution, not true deficiency

Causes of High Zinc

• Excessive supplementation: Doses above 40mg/day can cause copper deficiency, nausea, and immune suppression
• Contaminated water or food: Galvanised containers or industrial exposure
• Haemolysis: Red blood cell breakdown releases intracellular zinc (a lab artefact, not true elevation)

Important: Chronic zinc supplementation above 40mg/day can induce copper deficiency, leading to anaemia and neurological damage. Always balance zinc and copper intake.

How to Maintain Healthy Zinc Levels

• Eat zinc-rich foods: Oysters (highest source), red meat, poultry, crab, lobster, pumpkin seeds, chickpeas, cashews
• Soak and sprout grains/legumes: This reduces phytate content and improves zinc bioavailability
• Pair plant-based zinc with vitamin C: Citrus fruits, peppers, and tomatoes enhance zinc absorption
• Supplement wisely: 15–25mg daily is adequate for most adults; take on an empty stomach for best absorption
• Don't take zinc with iron or calcium: These minerals compete for absorption — take at different times
• Balance with copper: If supplementing zinc long-term, include 1–2mg copper to prevent deficiency

When Should You Get Tested?

• You experience frequent infections, slow wound healing, or persistent skin problems
• You have unexplained hair loss or altered sense of taste/smell
• You follow a vegetarian or vegan diet without careful zinc planning
• You have a malabsorption condition or liver disease
• You consume alcohol regularly
• You take PPIs or other medications that may reduce zinc absorption

Which Lola Health Tests Include Zinc?

• Peak Insights — our most comprehensive panel including zinc, selenium, and 70+ biomarkers