Effect of soy isoflavones and ascorbic acid supplementation on antioxidant activity in postmenopausal women
| ISRCTN | ISRCTN98074661 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN98074661 |
| Secondary identifying numbers | N/A |
- Submission date
- 04/01/2005
- Registration date
- 24/02/2005
- Last edited
- 19/09/2017
- Recruitment status
- No longer recruiting
- Overall study status
- Completed
- Condition category
- Signs and Symptoms
Prospectively registered
Protocol
Statistical analysis plan
Results
Individual participant data
Plain English summary of protocol
Not provided at time of registration
Contact information
Dr Andrea Hutchins
Scientific
Scientific
Department of Nutrition
Arizona State University
7001 East Williams Field Road
Mesa
85212
United States of America
| Phone | +1 480 727 1097 |
|---|---|
| andrea.hutchins@asu.edu |
Study information
| Study design | Randomised, double blind, crossover designed study |
|---|---|
| Primary study design | Interventional |
| Secondary study design | Randomised controlled trial |
| Study setting(s) | Not specified |
| Study type | Treatment |
| Scientific title | Effect of soy isoflavones and ascorbic acid supplementation on antioxidant activity in postmenopausal women: a randomised controlled trial |
| Study objectives | 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(s) | The Human Subjects Committee of the Institutional Review Board of Arizona State University approved this study; all participants gave written informed consent before participating. |
| Health condition(s) or problem(s) studied | 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 |
| Primary outcome measure | Lipid peroxides |
| Secondary outcome measures | 1. Vitamin C 2. Total cholesterol, including LDL, HDL and Triglycerides (TG) 3. Blood pressure |
| Overall study start date | 01/01/2002 |
| Completion date | 30/06/2002 |
Eligibility
| Participant type(s) | Patient |
|---|---|
| Age group | Adult |
| Sex | Female |
| Target number of participants | 10 |
| Key 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). |
| Key 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 |
| Date of first enrolment | 01/01/2002 |
| Date of final enrolment | 30/06/2002 |
Locations
Countries of recruitment
- United States of America
Study participating centre
Department of Nutrition
Mesa
85212
United States of America
85212
United States of America
Sponsor information
Arizona State University - Sustainable Technologies, Agribusiness and Resource Center (USA)
University/education
University/education
c/o John Brock
Center Coordinator
7001 East Williams Field Road
Arizona State University
Mesa
85212
United States of America
| john.brock@asu.edu | |
"ROR" |
https://ror.org/03efmqc40 |
Funders
Funder type
University/education
Arizona State University - Sustainable Technologies, Agribusiness and Resource Center (USA)
No information available
Results and Publications
| Intention to publish date | |
|---|---|
| Individual participant data (IPD) Intention to share | No |
| IPD sharing plan summary | Not provided at time of registration |
| Publication and dissemination plan | Not provided at time of registration |
| IPD sharing plan |
Study outputs
| Output type | Details | Date created | Date added | Peer reviewed? | Patient-facing? |
|---|---|---|---|---|---|
| Other publications | case report | 23/06/2005 | Yes | No | |
| Results article | results | 01/07/2005 | Yes | No |
Editorial Notes
19/09/2017: Publication reference added.
