Racial and Aging Effects of Acute Antioxidant Supplementation (RACE)

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.

Study Overview

• Status: Completed
• Conditions: Healthy
• Intervention / Treatment: Dietary supplement: Antioxidant; Other: Placebo

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.

• Study Type: Interventional
• Enrollment (Actual): 93
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Illinois
    • Chicago, Illinois, United States, 60612
      • University of Illinois - Chicago

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 75 years (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

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.

Exclusion Criteria:

• Current smoker
• Severe obesity (BMI>40 kg/m2)
• Blood pressure greater than 140/90 mmHg
• Diabetes (fasting glucose >110 mg/dl)
• Hyperlipidemia (total cholesterol >240 mg/dl)
• Inflammatory disease (rheumatoid arthritis, systemic lupus erythematosus, etc)
• Diagnosed atherosclerotic heart disease
• Diagnosed cardiac arrhythmia
• Bacterial, viral or upper respiratory infection within past 1 month
• Bleeding disorder
• Anticoagulant medication
• Pregnant women

Study Plan

How is the study designed?

Design Details

• Primary Purpose: PREVENTION
• Allocation: RANDOMIZED
• Interventional Model: CROSSOVER
• Masking: DOUBLE

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
PLACEBO_COMPARATOR: Placebo; Placebo will be ingested in front of laboratory personnel in two doses, separated by 30 minutes to increase absorption, consumed 90 and 60 minutes before the testing protocol. Placebo microcrystalline cellulose capsules will be of similar taste, color and appearance.	Dietary supplement: Antioxidant; Comparison of antioxidant supplementation with a placebo. Effects of race and age and race in repsonse to the supplementation will be evaluated.; Other Names: Vitamin E, Vitamin C, α-lipoic acid; Other: Placebo; Comparison of antioxidant supplementation with a placebo. Effects of race and age and race in repsonse to the supplementation will be evaluated.; Other Names: No other names
EXPERIMENTAL: Antioxidant; Supplementation will be ingested in front of laboratory personnel in two doses, separated by 30 minutes to increase absorption, consumed 90 and 60 minutes before the testing protocol. The first dose will consist of 300 mg of α-lipoic acid, 500 mg of vitamin C, and 200 IU of vitamin E, and the second dose will be 300 mg of α-lipoic acid, 500 mg of vitamin C, and 400 IU. of vitamin E.	Dietary supplement: Antioxidant; Comparison of antioxidant supplementation with a placebo. Effects of race and age and race in repsonse to the supplementation will be evaluated.; Other Names: Vitamin E, Vitamin C, α-lipoic acid; Other: Placebo; Comparison of antioxidant supplementation with a placebo. Effects of race and age and race in repsonse to the supplementation will be evaluated.; Other Names: No other names

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Arterial stiffness	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.	2 weeks
Arm blood flow	A second primary outcome is arm blood flow at rest and during two different intensities of hand grip exercise	2 weeks
Endothelial function	A third primary outcome is endothelial function assessed through brachial artery flow mediated dilation.	2 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Blood pressure	Both brachial and central blood pressure will be measured as secondary outcomes.	2 weeks

Collaborators and Investigators

• Sponsor: University of Illinois at Chicago
• Investigators: Principal Investigator: Bo Fernhall, Ph.D., University of Illinois at Chicago

Study record dates

Study Major Dates

• Study Start: April 1, 2014
• Primary Completion (ACTUAL): September 1, 2014
• Study Completion (ACTUAL): June 1, 2015

Study Registration Dates

• First Submitted: June 1, 2014
• First Submitted That Met QC Criteria: June 3, 2014
• First Posted (ESTIMATE): June 5, 2014

Study Record Updates

• Last Update Posted (ESTIMATE): June 16, 2015
• Last Update Submitted That Met QC Criteria: June 12, 2015
• Last Verified: June 1, 2015

More Information

Terms related to this study

• Keywords: aging; African Americans; antioxidants; healthy; vascular; racial differences; Caucasians
• Additional Relevant MeSH Terms: Physiological Effects of Drugs; Molecular Mechanisms of Pharmacological Action; Protective Agents; Micronutrients; Vitamin E; Vitamins; Antioxidants
• Other Study ID Numbers: 2013-0980