Healthy Dietary Intake Reduces Longitudinal Brain Iron Accumulation in Older Adults

Abstract

AbstractBackgroundBrain iron, which tends to accumulate with normal aging, negatively affects cognitive performance. However, the impact of brain iron on cognition appears modifiable. In a recent study from our group [1], we demonstrated that those older adults with high dietary intake of antioxidants, iron chelating nutrients and polyunsaturated fatty acids (Factor 2 in [1]), tended to have lower brain iron and better working memory performance than expected for their age. Here, we extend our previous work by evaluating associations between baseline consumption of Factor 2 nutrients and longitudinal brain iron accumulation, evaluated three years after baseline.MethodsForty‐three, cognitively normal, older adults (26 women, age range 63‐88 years) underwent MRI‐based structural brain imaging and quantitative susceptibility mapping for assessment of brain iron concentration at two time points: baseline (T1) and three years after baseline (T2). Additionally, at T1, nutritional‐intake was assessed via a validated questionnaire. Nutrients were grouped into nutrition factors based on previous literature and factor analysis. Factor 2, comprised vitamin E, lysine, DHA omega‐3 and LA omega‐6, representing antioxidants, iron chelating nutrients and polyunsaturated fatty acids.ResultsVoxelwise, whole‐brain, linear mixed‐effects models (qFDR < 0.05), controlling for longitudinal gray matter volume alterations, age, gender and education, revealed brain iron accumulation within several subcortical and cortical brain regions. Importantly, a significant time point by nutrition interaction was also observed. Specifically, those participants who consumed higher amounts of Factor 2 nutrients at baseline exhibited lower longitudinal brain iron accumulation within the left middle frontal gyrus, left superior parietal lobule, left insular cortex, right inferior temporal cortex, and bilateral hippocampus. Time point by nutrition interactions were not observed for other nutrition factors discussed in [1], such as those comprised of nutrients found in fruits and vegetables, or in green tea.ConclusionOur results indicate that dietary patterns rich in oxidative stress‐reducing antioxidants, iron chelating nutrients and polyunsaturated fatty acids may slow down age‐related, brain iron accumulation in older adults.