Translating β‐Glucan Immune Training to Humans

Many studies have explored biological response modifiers of the innate immune system to increase host resistance to pathogens, with β‐glucans ranking as one of the most widely researched. In conjunction with other standard immunomodulatory treatments, this strategy may offer a non‐specific protection potentially becoming a method of prevention and treatment for infections and enhancing the immune resistance of immuno‐compromised populations including the very young and older, frail people, and athletes. However, it must be acknowledged that, as the majority of the human studies available use primarily questionnaire‐based methodologies (addressing incidence, duration, and symptoms of infection) to draw conclusions, much uncertainty still exists about the evidence‐based relationship between β‐glucan supplementation in humans and consequent immunologic changes. This review organizes the existing human studies according to population, highlighting demographic, intervention, and outcome details for each study presented, according to the pre‐specified inclusion criteria indicated above, and with a focus on upper respiratory tract infection (URTI).