Dairy intake is associated with brain glutathione concentration in older adults.

BACKGROUND A reduction in key antioxidants such as glutathione has been noted in brain tissue undergoing oxidative stress in aging and neurodegeneration. To date, no dietary factor has been linked to a higher glutathione concentration. However, in an earlier pilot study, we showed evidence of a positive association between cerebral glutathione and dairy intake. OBJECTIVE We tested the hypothesis that dairy food consumption is associated with cerebral glutathione concentrations in older adults. DESIGN In this observational study, we measured cerebral glutathione concentrations in 60 healthy subjects (mean ± SD age: 68.7 ± 6.2 y) whose routine dairy intakes varied. Glutathione concentrations were measured by using a unique, noninvasive magnetic resonance chemical shift imaging technique at 3 T and compared with dairy intakes reported in 7-d food records. RESULTS Glutathione concentrations in the frontal [Spearman's rank-order correlation (rs) = 0.39, P = 0.013], parietal (rs = 0.50, P = 0.001), and frontoparietal regions (rs = 0.47, P = 0.003) were correlated with average daily dairy servings. In particular, glutathione concentrations in all 3 regions were positively correlated with milk servings (P ≤ 0.013), and those in the parietal region were also correlated with cheese servings (P = 0.015) and calcium intake (P = 0.039). Dairy intake was related to sex, fat-free mass, and daily intakes of energy, protein, and carbohydrates. However, when these factors were controlled through a partial correlation, correlations between glutathione concentrations and dairy and milk servings remained significant. CONCLUSIONS Higher cerebral glutathione concentrations were associated with greater dairy consumption in older adults. One possible explanation for this association is that dairy foods may serve as a good source of substrates for glutathione synthesis in the human brain.