Proceedings of the Nutrition Society

Symposium on ’Nutrition, infection and immunity‘

Vitamin A and immunity to viral, bacterial and protozoan infections

R. D. Sembaa1 c1

a1 Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA


Studies in animal models and cell lines show that vitamin A and related retinoids play a major role in immunity, including expression of mucins and keratins, lymphopoiesis, apoptosis, cytokine expression, production of antibody, and the function of neutrophils, natural killer cells, monocytes or macrophages, T lymphocytes and B lymphocytes. Recent clinical trials suggest that vitamin A supplementation reduces morbidity and mortality in different infectious diseases, such as measles, diarrhoeal disease, measles-related pneumonia, human immunodeficiency virus infection and malaria. Immune responses vary considerably during different infections, and the available data suggest that the modulation of immune function by vitamin A may also vary widely, depending on the type of infection and immune responses involved.


c1 Corresponding Author: Dr R. D. Semba, fax +1 410 955 0629, email