This was reportedly the first registered human trial to evaluate the effects of India-based Akay Bioactives’ capsaicin ingredient, Capsifen, on cerebrovascular function and cognition in middle-aged and older adults who are overweight or obese.
The researchers at the University of Southern Queensland in Australia noted that the findings provide preliminary evidence that “chronic capsaicin supplementation may improve cognition and neurovascular coupling in humans”.
“A key finding was that the total cerebrovascular responsiveness increased in the supplement group “reflecting an enhanced cerebrovascular response during periods of increased neuronal metabolism,” they noted in Nutrients.
How does capsaicin affect the aging brain?
Neurovascular coupling and cerebrovascular reactivity are two distinct but complementary mechanisms that regulate blood flow in the brain and enable it to meet metabolic demands.
These processes change and undergo remodeling as people age, playing a key role in the brain’s vulnerability to neurodegenerative diseases. The mechanisms are also useful as markers for detecting pathological changes during brain monitoring.
The study highlights how obesity, coupled with aging, can affect cognition and brain function. Key to the potential mechanisms is nitric oxide (NO), which helps to regulate blood vessel tone and vascular remodeling in the brain.
Obesity can cause reduced NO availability, oxidative stress, and inflammation, which impacts the aging brain.
“Therefore, the reductions in cerebrovascular function and cognition observed during normal ageing may be exacerbated by obesity,” the study noted.
Previous animal research has demonstrated that capsaicin may reduce systemic inflammation, oxidative stress, and adiposity. The current study is reportedly the first trial to investigate the cerebrovascular effects in humans, which the researchers noted may be due to capsaicin’s pungency-related side effects such as gastrointestinal irritation.
However, encapsulated supplements such as Capsifen provide a more tolerable and safer method for administering capsaicin in human trials, while avoiding side effects, the researchers noted.
Although the study didn’t directly assess the mechanisms involved, the researchers speculated that capsaicin may activate the endothelial transient receptor potential vanilloid 1 (TRPV1), thereby promoting the synthesis and release of NO. This mechanism could account for the observed improvements in exercise performance.
Study details
The researchers randomly allocated 34 adults aged 50 to 80 with a body mass index (BMI) of at least 25 kg/m to consume 200 mg/day of Capsifen or a placebo for 12 weeks.
Before and after the intervention, the participants underwent anthropometric, cardiovascular, respiratory, exercise performance, handgrip strength, cerebrovascular, and cognitive assessments, and completed the Profile of Mood States (POMS) questionnaire. They also had biomarkers evaluated through blood samples.
The findings revealed that the total cerebrovascular responsiveness (CVR) to cognitive stimuli increased following Capsifen and decreased in the placebo group. Total cognition also increased following Capsifen supplementation compared with the placebo, but the supplement did not alter CVR to hypercapnia (elevated carbon dioxide).
“Working memory, executive function and exercise performance also improved, while waist circumference and waist-to-hip ratio decreased,” wrote the researchers.
However, they noted that the anthropometric results should be interpreted cautiously and recommended further studies with larger sample sizes and longer follow-up periods to confirm their findings.
Source: Nutrients; doi: https://doi.org/10.3390/nu18213613; “The Preliminary Effects of Capsaicin Supplementation on Cerebrovascular Function and Cognition in Middle-Aged and Older Adults Who Are Overweight or Obese.” Authors: T. Thornton et al.
