The Effect of Milk Components on the Immune Response to a Pneumonia Vaccine: A Randomized Placebo‐controlled Clinical Trial

Abstract

Interventions aimed at improving immune function in the elderly could significantly reduce their risk of infectious disease and resulting mortality. The immune benefits of breast milk consumption in human infants are well established and suggest bovine milk components may also help enhance immune function in older populations. The objectives of this study were to evaluate the effects of a milk‐protein supplement on immune function in people at risk of immune senescence (IS). We enrolled 160 subjects over age 50 who were randomized to consume a milk‐based or control supplement for 8 weeks. Immune function was evaluated by measuring the antibody response to a pneumonia vaccine. IgG antibodies were measured before and after vaccine by multi‐analyte immunodetection system. Seroconversion was defined as a 4‐fold increase in titer. Risk of IS was evaluated by measuring a previously described marker of immune function, indolamine 2,3‐dioxygenase (IDO). IDO activity was defined as the ratio of the serum concentration of enzyme product (kynurenine) to substrate (tryptophan), measured by HPLC. Results from this study show a milk intervention significantly (p<0.05) increased the antibody response to 5 vaccine serotypes and the average seroconversion rate. These results highlight the relevance of diet for improving age‐related immune decline in individuals at risk of immune senescence.Grant Funding Source: Dairy Management, Inc, National Dairy Council, the UC Discovery Grant