Dairy intake is associated with brain glutathione concentration in older adults

• Published in: The American journal of clinical nutrition 2015-02, Vol.101 (2), p.287-293
• Main Authors: Choi, In-Young, Lee, Phil, Denney, Douglas R, Spaeth, Kendra, Nast, Olivia, Ptomey, Lauren, Roth, Alexandra K, Lierman, Jo Ann, Sullivan, Debra K
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Antioxidants; Body Height; Body Weight; brain; calcium; Calcium, Dietary - administration & dosage; carbohydrates; Cerebrum - chemistry; cheeses; clinical nutrition; correlation; dairy consumption; Dairy Products; Diet; elderly; energy intake; fat free mass; Female; food records; glutathione; Glutathione - chemistry; Humans; image analysis; Magnetic Resonance Imaging; Male; Middle Aged; Milk; Nutrition Assessment; Nutrition Policy; Nutritional Status, Dietary Intake, and Body Composition; observational studies; Older people; Oxidative stress; Tissues; Waist Circumference
• ISSN: 0002-9165; 1938-3207
• DOI: 10.3945/ajcn.114.096701

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 (r ₛ) = 0.39, P = 0.013], parietal (r ₛ = 0.50, P = 0.001), and frontoparietal regions (r ₛ = 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.