Impact of Sex in the Effect of Dietary Capsaicin on Cardiovascular Health

Specific Aim 1: Determine the sex-specific effects of dietary capsaicin on central and peripheral blood pressure and arterial stiffness. The investigators hypothesize that dietary capsaicin intervention (6 week) will improve BP and arterial stiffness, likely in a sex-dependent manner. The investigators will measure heart rate variability and excretion of capsaicin and metabolites to ascertain bioavailability, and understand the mechanistic role of the autonomic nervous system, in capsaicin's effect on BP.

Specific Aim 2: Assess whether dietary capsaicin effects on vascular function is sex-specific. The investigators hypothesize that dietary capsaicin intervention (6 week) will improve NO bioavailability, through improved redox balance and lowered asymmetric dimethylarginine, thereby improving peripheral vascular function, likely in a sex-dependent manner.

Utilizing a double-blind, randomized, placebo-controlled, design the investigators will investigate whether there is sex-specificity in the effects of a 6-week dietary capsaicin intervention on nitric oxide (NO) bioavailability, BP, vascular function, and arterial stiffness.

• Dietary capsules (Dietary supplement): Daily doses of dietary capsaicin or placebo in capsule form

Primary outcomes

• Blood Pressure and Vascular Stiffness [Baseline, 24 hours, and 6-weeks]: The investigators will assess peripheral and estimated central blood pressures and vascular stiffness using pulse wave analysis.
• Heart Rate (HR) and HR variability (HRV) [Baseline, 24 hours, and 6-weeks]: The investigators will assess HR and HRV using electrocardiogram and standard techniques to determine time and frequency domain estimates of HRV.
• Flow Mediated Dilation [Baseline, 24 hours, and 6-weeks]: The investigators will assess brachial artery flow-mediated dilation using ischemia-reperfusion and ultrasound doppler to assess the dilatory capacity and reactive hyperemia.
• Passive Leg Movement Hyperemia [Baseline, 24 hours, and 6-weeks]: The investigators will assess the hyperemic response to passive leg movement using ultrasound doppler.
• Near Infrared Spectroscopy (NIRS) Vascular Occlusion Test [Baseline, 24 hours, and 6-weeks]: The investigators will assess the metabolic capacity and vascular reactivity using ischemia-reperfusion and NIRS

Secondary outcomes

• Urinary Capsaicinoids [Baseline, 24 hours, and 6-weeks]: The investigators will collect urine to determine urinary capsaicin and associated metabolites to understand bioavailability and potential relation to function.
• Blood Lipids [Baseline and 6-weeks]: The investigators will collect blood to determine blood lipids (cholesterol) and glucose.

Sex: All, ages: 18 Years to any, accepts healthy volunteers

Inclusion Criteria:

* relatively healthy (other than elevated blood pressure) non-smoking men and women over the age of 18 from the local community

Exclusion Criteria:

* Women who are without a period (not due to a birth control method, intrauterine device or menopause), are pregnant, attempting to conceive, or are breastfeeding will be excluded.
* uncontrolled hypertension
* Anyone with severe illness or compromised or suppressed immune system (e.g. taking immune suppressants, chronic viral infection or treatment).
* Any participants with excessive sensitivity to spicy foods or fiber (psyllium husk) will be excluded
* Participants with food allergies will be excluded
* Participants who have difficulty swallowing or swallowing pills may be excluded.
* Participants who suffer from heartburn, hiatal hernia, gastritis, or peptic ulcer disease may be excluded.