The effect of acute cocoa flavanol intake on the BOLD response and cognitive function in type 1 diabetes: a randomized, placebo-controlled, double-blinded cross-over pilot study.

RATIONALE: Type 1 diabetes (T1D), a chronic autoimmune disease, can result in cognitive dysfunction and is associated with vascular dysfunction. Cocoa flavanols (CFs) can stimulate nitric oxide-dependent vasodilation, resulting in enhanced hemodynamic responses and better cognitive function. OBJECTIVES: To investigate whether acute CF supplementation can improve cognitive function and hemodynamic responses in T1D. METHODS: In this randomized, double-blinded, cross-over pilot study, 11 patients with T1D and their healthy matched controls consumed CF (900 mg CF) and placebo (15 mg CF) 2 h before a flanker test. fMRI was used to measure blood oxygen level-dependent (BOLD) response during the cognitive test. Repeated measure ANOVAs were used to test the effects of CF and T1D on BOLD response and cognitive performance. RESULTS: CF improved reaction time on the flanker test and increased the BOLD response in the supramarginal gyrus parietal lobe and inferior frontal gyrus, compared to placebo, in both groups. In patients with T1D, cognitive performance was not deteriorated while the BOLD response was smaller in T1D compared to healthy controls in the subgyral temporal lobe and the cerebellum. CONCLUSIONS: Acute CF intake improved reaction time on the flanker test and increased the BOLD response in the activated brain areas in patients with T1D and their matched controls.