The Preliminary Effects of Capsaicin Supplementation on Cerebrovascular Function and Cognition in Middle-Aged and Older Adults Who Are Overweight or Obese

Background/Objectives: Cerebrovascular function and cognition decline with age and may be further exacerbated by obesity. Capsaicin may improve cerebrovascular function and cognition, although evidence in humans is lacking. We investigated the effects of 12 weeks of capsaicin supplementation on cerebrovascular function and cognition in middle-aged and older adults who were overweight or obese. Methods: Forty participants were randomly allocated to receive 200 mg/day of Capsifen® or a placebo, with 34 completing the intervention (n = 17 in both). Before and after supplementation, transcranial Doppler ultrasonography was used to measure the cerebrovascular responsiveness (CVR) to physiological (hypercapnia, 5% carbon dioxide) and cognitive stimuli, while cognition was assessed using a comprehensive cognitive battery. The trial was prospectively registered (ACTRN12623000556640). Results: Total CVR to cognitive stimuli increased following Capsifen® supplementation (18 ± 3% to 21 ± 1%) and decreased in the placebo group (21 ± 4% to 19 ± 3%; p = 0.0002). Total cognition increased following Capsifen® supplementation (98 ± 18 to 107 ± 18) compared with the placebo (105 ± 13 to 106 ± 10; p = 0.0085). Capsifen® did not alter CVR to hypercapnia (30 ± 18% to 44 ± 27% vs. 39 ± 23% to 32 ± 16%; p = 0.5981). Working memory, executive function and exercise performance also improved, while waist circumference and waist-to-hip ratio decreased. Conclusions: Twelve weeks of Capsifen® supplementation improved total cognition and CVR to cognitive stimuli but not CVR to hypercapnia. These findings provide preliminary evidence that chronic capsaicin supplementation may improve cognition and neurovascular coupling in humans.