Vitamin A deficiency is linked to increased risk of respiratory infections, diarrhea, and severe measles, with meta-analyses showing reduced all-cause mortality and improved pneumonia symptoms in children treated with vitamin A.

“Vitamin A deficiency predisposes to respiratory infections, diarrhea, and severe measles. Systematic reviews and meta-analysis of trials in children with vitamin A report reduced all-cause mortality and improved symptoms of acute pneumonia. A meta-analysis of 15 randomized controlled trials involving 3021 children with pneumonia treated with vitamin A as an adjuvant therapy found that vitamin A supplementation helped to relieve clinical symptoms and shorten the length of hospital stay.”