Antioxidant vitamins reduce acute meal-induced memory deficits in adults with type 2 diabetes

Memory impairment is observed in adults with type 2 diabetes mellitus (T2DM), with further acute deficits after meal ingestion. This study explored whether postprandial oxidative stress was a contributor to these meal-induced memory deficits. Sixteen adults with T2DM (mean age, 63.5 +/- 2.1 years) who were not regularly taking high-dose antioxidant supplements were fed a high-fat meal, the same test meal with vitamins C (1000 mg) and E (800 IU) tablets, or water on 3 separate occasions. After meal ingestion, a battery of cognitive tests were administered, which included measures of delayed verbal memory, assessed at 60 and 105 minutes after meal ingestion. Relative to water consumption, the high-fat meal resulted in poorer performance at 105 minutes postingestion on measures of delayed verbal recall (word list and paragraph recall) and working memory (Digit-Span Forward). Coconsumption of antioxidant vitamins and high-fat meal prevented this meal-induced deficit such that performance on these tasks was indistinguishable from that after water intake. At the same time point, a small but significant improvement on the word-naming and color-naming components of Stroop was observed after meal ingestion, relative to water, irrespective of whether antioxidants were consumed, demonstrating the specificity of meal-induced impairments to memory function. Executive function, assessed by Trails Parts A and B, was not influenced by meal or antioxidant ingestion. In adults with T2DM, coconsumption of antioxidant vitamins minimizes meal-induced memory impairment, implicating oxidative stress as a potential contributor to these decrements.