Can inflammation cause low blood zinc and selenium levels even when intake is adequate?

Systemic inflammation triggers a physiological shift in mineral metabolism known as the acute-phase response (APR), which significantly alters the interpretation of blood tests for zinc and selenium. This process results in a redistribution of these micronutrients from the bloodstream into tissues, causing serum levels to decline rapidly even if nutritional intake is adequate.

Clinical and effectiveness evidence

In the presence of systemic inflammation—often indicated by a C-reactive protein (CRP) level greater than 5 mg/L—serum zinc and selenium concentrations behave as "negative acute-phase reactants."

• Zinc distortion: Studies from the BRINDA project indicate that unadjusted serum zinc measurements can overestimate the prevalence of deficiency by 10% to 20% in populations with high inflammation.
• Selenium correlation: Serum selenium and its primary transporter, selenoprotein P (SELENOP), show strong inverse correlations with inflammatory markers like IL-6 and CRP.
• Adjustment protocols: Research suggests that interpreting these mineral levels requires concurrent testing of inflammatory markers. Statistical adjustment factors or regression models are often necessary to distinguish between a true nutritional deficit and inflammation-induced redistribution.

Mechanistic explanations

The drop in circulating minerals is driven by specific cytokine-mediated pathways that redirect zinc and selenium to hepatocytes and other high-demand tissues.

• Zinc sequestration: Pro-inflammatory cytokines, particularly Interleukin-6 (IL-6), upregulate the expression of the ZIP14 (Slc39a14) transporter in the liver. This protein facilitates a rapid influx of zinc from the plasma into liver cells, effectively sequestering the mineral.
• Selenium transport changes: Inflammation downregulates the hepatic synthesis of selenoprotein P, the primary plasma carrier for selenium. Concurrently, selenium may be redirected to tissues with high antioxidant demands via receptor-mediated uptake (such as ApoER2) to combat oxidative stress.
• Albumin reduction: As a negative acute-phase reactant, albumin—the primary carrier for zinc in the blood—decreases during inflammation, further lowering the total carrying capacity of the blood for these minerals.

Bottom line

Inflammation triggers a coordinated redistribution of zinc and selenium into tissues, causing circulating blood levels to plummet. Because these minerals act as negative acute-phase reactants, low serum readings during illness or chronic inflammation often reflect this physiological shift rather than a lack of dietary intake.