Which deficiency is commonly associated with being more susceptible to infections?

Which deficiency is commonly associated with being more susceptible to infections?

• A. Iron deficiency
• B. Vitamin B12 deficiency
• C. Vitamin D deficiency
• D. Magnesium deficiency

Answer: (C)

Vitamin D status directly influences immune defense. Immune cells have vitamin D receptors and respond by producing antimicrobial peptides that help protect surfaces like the skin and mucous membranes. When vitamin D is deficient, these antimicrobial defenses are weaker, and immune regulation can be less effective, which helps explain why low vitamin D is linked with a higher risk of infections, especially respiratory infections. Some studies also show that correcting a deficiency can reduce infection risk in deficient individuals. The other deficiencies affect different systems—iron deficiency mainly causes anemia and fatigue and can indirectly impact immunity, while B12 and magnesium deficiencies disrupt red blood cell production or broad metabolic processes but do not have as strong a, direct connection to infection susceptibility as vitamin D does.

Vitamin D status directly influences immune defense. Immune cells have vitamin D receptors and respond by producing antimicrobial peptides that help protect surfaces like the skin and mucous membranes. When vitamin D is deficient, these antimicrobial defenses are weaker, and immune regulation can be less effective, which helps explain why low vitamin D is linked with a higher risk of infections, especially respiratory infections. Some studies also show that correcting a deficiency can reduce infection risk in deficient individuals. The other deficiencies affect different systems—iron deficiency mainly causes anemia and fatigue and can indirectly impact immunity, while B12 and magnesium deficiencies disrupt red blood cell production or broad metabolic processes but do not have as strong a, direct connection to infection susceptibility as vitamin D does.