Healthy
Conditions
Keywords
antioxidants, Caucasians, healthy, African Americans, vascular, aging, racial differences
Brief summary
This research is,being done to better understand how antioxidants (vitamins C, E and Alpha Lipoic Acid) af,f,ect the heart,and arteries. For this study, we will obtain blood samples to measure oxidative stress markers (substances in the blood that are linked to oxidative stress), cholesterol, insulin and blood glucose (sugar), as well as measure how well the heart and arteries are working following supplementation with the antioxidants. Our central hypothesis is that acute antioxidant supplementation will improve arterial function at rest and during exercise in African Americans without an impact of age, whereas aging will modify these effects in Caucasians.
Detailed description
The overall goal of this application is to investigate the effect of aging on how acute antioxidant supplementation affects decrements in arterial function observed in African Americans (AA). Additionally, this application will facilitate the applicant's emergence as an independent investigator in integrative clinical physiology. Oxidative stress (OS), contributes to hypertension, diabetes, heart failure, atherosclerosis, sepsis and aging. Increased OS leads to the development of endothelial dysfunction and subsequent development of cardiovascular disease through the inactivation of nitric oxide (NO) by superoxide (O2) and other free radicals. African Americans (AA) have increased OS and inflammation in vivo and in vitro, and have a lower serum concentration of most antioxidants. Endothelial cells of AAs have steady state NO/ O2/ONOO- balance that is close to redox state, which is a characteristic of endothelium impaired function disorders. Endothelium-derived NO is a vasodilator and inhibits monocyte adhesion and platelet activity and therefore is important in the maintenance of vascular homeostasis. These specific differences in OS could be a contributing mechanism to the high prevalence of cardiovascular disease, especially hypertension and heart failure, observed in AA. Aging causes increases in OS, endothelial dysfunction, and decreased arterial compliance, thus increasing the risk of cardiovascular disease. Acute supra-physiological dosages of antioxidants have been shown to transiently restore endothelial function in older adults and patients with coronary artery disease and hypertension by scavenging free radicals.However, it is unknown if acute antioxidant supplementation can diminish differences in vascular function between AA and Caucasians (CA). It is also unknown if acute antioxidant supplementation with known efficacy will differentially affect blood flow in AA vs CA during exercise.
Interventions
DIETARY_SUPPLEMENTAntioxidant
Comparison of antioxidant supplementation with a placebo. Effects of race and age and race in repsonse to the supplementation will be evaluated.
OTHERPlacebo
Comparison of antioxidant supplementation with a placebo. Effects of race and age and race in repsonse to the supplementation will be evaluated.
Sponsors
University of Illinois at Chicago
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
PREVENTION
Masking
DOUBLE (Subject, Investigator)
Eligibility
Sex/Gender
ALL
Age
18 Years to 75 Years
Healthy volunteers
Yes
Inclusion criteria
* 18-35 or 55-75 years of age * General Good health * Without diagnosed atherosclerotic disease * Without metabolic or inflammatory disease * Do not use antioxidant vitamin supplementation * Do not use anti-inflammatory medication within last 2 weeks * Do not use steroidal substances within past 2 weeks * Participants on medications (not listed in the
Exclusion criteria
) will take medication as normal on all days of study visits.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Endothelial function | 2 weeks | A third primary outcome is endothelial function assessed through brachial artery flow mediated dilation. |
| Arterial stiffness | 2 weeks | The overall aim of this study is to examine the effects of an acute dose of an antioxidant cocktail on arterial stiffness (measured by ventral pulse wave velocity) in younger and older African Americans in comparison to younger and older Caucasians. |
| Arm blood flow | 2 weeks | A second primary outcome is arm blood flow at rest and during two different intensities of hand grip exercise |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Blood pressure | 2 weeks | Both brachial and central blood pressure will be measured as secondary outcomes. |
Countries
United States
Outcome results
None listed