Healthy dietary intake moderates the effects of age on brain iron concentration and working memory performance.

Age-related brain iron accumulation is linked with oxidative stress, neurodegeneration and cognitive decline. Certain nutrients can reduce brain iron concentration in animal models, however, this association is not well established in humans. Moreover, it remains unknown if nutrition can moderate the effects of age on brain iron concentration and/or cognition. Here, we explored these issues in a sample of 73 healthy older adults (61-86 years old), while controlling for several factors such as age, gender, years of education, physical fitness and alcohol-intake. Quantitative susceptibility mapping was used for assessment of brain iron concentration and participants performed an N-Back paradigm to evaluate working memory performance. Nutritional-intake was assessed via a validated questionnaire. Nutrients were grouped into nutrition factors based on previous literature and factor analysis. One factor, comprised of vitamin E, lysine, DHA omega-3 and LA omega-6 PUFA, representing food groups such as nuts, healthy oils and fish, moderated the effects of age on both brain iron concentration and working memory performance, suggesting that these nutrients may slow the rate of brain iron accumulation and working memory declines in aging.