Study protocol: A randomised, double blinded, placebo‐controlled clinical trial testing the effects of a vitamin D‐enriched mushroom supplement on cognitive performance and mood in healthy elderly adults

Abstract

Background: Cross‐sectional evidence suggests a positive relationship between vitamin D status and cognitive performance and mood; however, interventional clinical evidence is lacking. Vitamin D deficiency is prevalent in the elderly. If justified, supplementation offers a potentially cost‐effective approach for maintaining cognitiondependent quality of life in aging populations. Exposure to UV light elevates the vitamin D content of mushrooms, which represent a novel and convenient source of dietary vitamin D (D2). Here we present the protocol for a study to determine whether increasing vitamin D status improves cognitive function, mood and depressive symptoms in healthy older subjects. Methods: The study is a double blind, placebo‐controlled clinical trial with 400 healthy male and female subjects aged 60–90 years old. Subjects pre‐screened for confounders of cognition but not vitamin D status, are randomised across four groups, receiving daily supplement treatments in parallel over six months; either: vitamin D2‐enriched mushroom solids, vitamin D3 alone, standard mushroom solids, or placebo. Primary endpoints are: changes in serum 25‐OH‐D2 and 25‐OH‐D3 metabolites and general cognitive performance. Secondary endpoints include mood and depressive symptoms. Data analysis will adjust for covariate measures. Blood samples taken at the three clinic visits (baseline, 5 weeks and 6 months) will be stored.