The Association of Dietary Iron on Visual Cognitive Performance and Training in the IONSport Study

Abstract Objectives Visual cognitive performance (VCP) is an important factor in high-speed interactions with the environment such as sports or driving, however, the testing, training and determination of factors that influence this ability has been elusive. Iron intake from heme sources has been shown to prevent altered metabolic processes, reductions in protein and neurotransmitter synthesis, and cognitive abilities and neural functions. The purpose of this study is to determine whether chronic dietary iron intake explain the large difference in VCP and training responses between healthy individuals. Methods Men and women age 18–35 completed 15 visual cognitive training sessions (Neurotracker) in 10 visits to the laboratory. On the days of training, all food intake was documented (Nutribase) along with measures of body composition, blood pressure, hydration status, sleep patterns, and recent exercise. Mean nutritional intakes were calculated for the 10 days of food records. Total daily intakes of iron were also calculated for each of the 10 days of food records. Results Iron intake was significantly associated to VCP (P < 0.001) in women (N = 52) but not men (N = 36). VCP improved progressively with dietary iron intake in women from low (iron: 8.2 ± 1.2 mg/day, VCP: 1.38 ± 0.22, N = 24), medium (iron: 13.4 ± 1.3 mg/day, VCP = 1.59 ± 0.38, N = 21) to high (20.9 ± 3.8 mg/day, VCP = 1.86 ± 0.33, N = 7) in which all groups were all significantly different from each other (P < 0.05). Conclusions These results suggest that intakes of iron at or above the RDA may be essential to optimize VCP. Funding Sources National Cattlemen's Beef Association.