Condition category
Signs and Symptoms
Date applied
04/01/2005
Date assigned
24/02/2005
Last edited
14/03/2008
Prospective/Retrospective
Retrospectively registered
Overall trial status
Completed
Recruitment status
No longer recruiting

Plain English Summary

Not provided at time of registration

Trial website

Contact information

Type

Scientific

Primary contact

Dr Andrea Hutchins

ORCID ID

Contact details

Department of Nutrition
Arizona State University
7001 East Williams Field Road
Mesa
85212
United States of America
+1 480 727 1097
andrea.hutchins@asu.edu

Additional identifiers

EudraCT number

ClinicalTrials.gov number

Protocol/serial number

N/A

Study information

Scientific title

Acronym

Study hypothesis

This study investigated the extent to which vitamin C and isoflavones, as single or combined supplements to a habitual diet, provided antioxidant effects by reducing lipid oxidation in blood. Healthy, non-smoking, postmenopausal women were screened for regular soy consumption (one serving per day), vitamin C supplementation (60 mg/day), and postmenopausal status.

Utilising a randomised, double blind, crossover design, ten subjects were assigned to one of four dietary treatments. Subjects were instructed to continue their habitual physical activity and dietary habits during the 14-week experiment. The subjects completed consecutive two-day diet and activity logs immediately prior to each fasted blood draw. Diet and activity logs were analysed. Fasting blood was collected in vacuutainers, centrifuged, and plasma aliquots were frozen at -70°C for later analysis.

Plasma vitamin C concentration was determined using a 2,4-dinitrophenylhydrazine method by Omaye. Lipid peroxides were measured using the flurometric method. Total cholesterol was determined by a photometric assay; high-density lipoprotein (HDL) cholesterol by a homogenous enzyme immunoassay; and, triglycerides and low-density lipoprotein (LDL) cholesterol by a colorimetric assay (performed by Sonora Quest Laboratories, Phoenix, AZ).

Ethics approval

The Human Subjects Committee of the Institutional Review Board of Arizona State University approved this study; all participants gave written informed consent before participating.

Study design

Randomised, double blind, crossover designed study

Primary study design

Interventional

Secondary study design

Randomised controlled trial

Trial setting

Not specified

Trial type

Treatment

Patient information sheet

Condition

Antioxidant markers and risk factors for heart disease

Intervention

Ten subjects were assigned to one of four dietary treatments:
1. Supplement of 5 mg isoflavones per kg/body weight (IF)
2. 500 mg vitamin C supplement (VC)
3. Supplement of 5 mg isoflavones per kg/body weight and 500 mg vitamin C supplement (IF-VC)
4. Placebo (C)

The two week treatment periods were separated by a two week washout period.

Intervention type

Supplement

Phase

Not Specified

Drug names

Vitamin C and isoflavones

Primary outcome measures

Lipid peroxides

Secondary outcome measures

1. Vitamin C
2. Total cholesterol, including LDL, HDL and Triglycerides (TG)
3. Blood pressure

Overall trial start date

01/01/2002

Overall trial end date

30/06/2002

Reason abandoned

Eligibility

Participant inclusion criteria

Healthy, nonsmoking, postmenopausal women were screened for regular soy consumption (less than or equal to one serving per day), vitamin C supplementation (less than or equal to 60 mg/day), and postmenopausal status (one year).

Participant type

Patient

Age group

Adult

Gender

Female

Target number of participants

10

Participant exclusion criteria

1. Vegetarianism
2. Current or past diagnosis of cancer
3. Cardiovascular disease or diabetes
4. Chronic illness or inflammation
5. Gastrointestinal disorders
6. Recent (previous six months) use of antibiotics, and use of hypoglycaemic or hypolipidaemic medication
7. Body mass index (BMI) less than or equal to 35 kg/m^2
8. Consumed less than or equal to two alcoholic drinks per day

Recruitment start date

01/01/2002

Recruitment end date

30/06/2002

Locations

Countries of recruitment

United States of America

Trial participating centre

Department of Nutrition
Mesa
85212
United States of America

Sponsor information

Organisation

Arizona State University - Sustainable Technologies, Agribusiness and Resource Center (USA)

Sponsor details

c/o John Brock
Center Coordinator
7001 East Williams Field Road
Arizona State University
Mesa
85212
United States of America
john.brock@asu.edu

Sponsor type

University/education

Website

Funders

Funder type

University/education

Funder name

Arizona State University - Sustainable Technologies, Agribusiness and Resource Center (USA)

Alternative name(s)

Funding Body Type

Funding Body Subtype

Location

Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Results - basic reporting

Publication summary

Case report in: http://www.ncbi.nlm.nih.gov/pubmed/15975148

Publication citations

  1. Case report

    Hutchins AM, McIver IE, Johnston CS, Hypertensive crisis associated with high dose soy isoflavone supplementation in a post-menopausal woman: a case report [ISRCTN98074661]., BMC Womens Health, 2005, 5, 9, doi: 10.1186/1472-6874-5-9.

Additional files

Editorial Notes