The Effect of a Nutritional Supplement in Individuals With Type 2 Diabetes Mellitus: a Pilot Study

January 5, 2012 updated by: University of Sydney

The Effect of a Nutritional Supplement on Cardiometabolic, Inflammatory, and Oxidative Stress Markers in Individuals With Type 2 Diabetes Mellitus: a Pilot Study

Diabetes Mellitus (DM) is a major risk factor for cardiovascular disease, with 50% of diabetes-associated deaths being attributed to cardiovascular complications. The characterising features of DM include: the presence of chronic hyperglycaemia, consequent upon decreased secretion or action of insulin; dyslipidaemia; and enhanced levels of oxidative stress and inflammation. Zinc and omega 3 polyunsaturated fatty acids have been shown to influence each of these outcomes via several mechanisms. This pilot study will examine the effect of nutritional supplements containing zinc and omega 3 on these outcomes in a population with type 2 DM.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

The prevalence of type 2 DM and related-complications continues to increase. Diet is a significant factor in the aetiology of type 2 DM. Intakes of zinc and omega 3 fatty acids may modulate glycaemic control, lipid metabolism, and inflammatory processes in the disease. Zinc is involved in many biological processes that include enzyme action, stabilisation of cell membranes, regulation of gene expression, and cell signalling. Zinc supplementation has been demonstrated to improve glycaemic control in both animals and humans. The normalising effect of zinc on glucose homeostasis may relate to its involvement in insulin metabolism. Zinc functions in the synthesis, storage, secretion, and action of insulin. Omega-3 also enhances glycaemic control and dietary supplementation with omega-3 polyunsaturated fatty acids has been shown to improve insulin sensitivity in subjects with DM. Both zinc and omega-3 function to mediate lipid metabolism. Zinc supplementation has been found to be associated with a beneficial increase in HDL cholesterol concentrations in individuals with type 2 DM. The mechanism may again involve insulin, which has been proposed as an independent predictor of plasma HDL. Omega-3 directly activates transcription factors that regulate lipid metabolism and is known to decrease serum triglyceride levels in DM. Zinc appears to beneficially impact oxidative stress-related parameters in DM via a range of mechanisms, including the regulation of copper,zinc superoxide dismutase, metallothionein, NF-κB and nitric oxide signaling. The purpose of this pilot study is to explore the effect of zinc and omega 3 supplementation on hyperglycaemia, dyslipidaemia, chronic inflammation, and oxidative stress in a population with type 2 DM.

This study will recruit 48 postmenopausal women with type 2 DM. Participants will be randomly allocated to one of 4 groups for a period of 12 weeks: placebo, zinc, omega 3, or zinc + omega 3 supplementation. Usual dietary intake will be assessed before and after the trial period using 2-day estimated food records, which will be checked by a research dietitian. Blood samples will be collected from all participants at the start of the intervention (week 0) then at 4 weekly intervals (weeks 4, 8, 12) by qualified phlebotomists. Blood samples will be analysed for plasma zinc, plasma lipids and fatty acids, markers of inflammation and oxidative stress, and indicators of glycaemic control. An aliquot of blood will also be used for the measurement of zinc transporter mRNA levels utilising real-time quantitative PCR techniques.

Study Type

Interventional

Enrollment (Actual)

48

Phase

  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Australia
    • New South Wales
      • Sydney, New South Wales, Australia, 2006
        • University of Sydney

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

48 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

Female

Description

Inclusion Criteria:

  • Female, postmenopausal
  • Type 2 diabetes (controlled by diet and lifestyle; or oral hypoglycaemic medication (i.e. metformin) for not more than 7 years)
  • Normal Glomerular Filtration Rate (GFR) and normal microalbumin/creatine ratio
  • No nutritional supplements in the 6 weeks prior to the trial & continuing through the trial period
  • Non-smoking

Exclusion Criteria:

  • Diagnosed with current major illness (renal disease, significant cardiovascular disease, gastrointestinal disorders, cancer, or other significant disorder likely to interfere with zinc metabolism)
  • Taking medications that are likely to interfere with zinc metabolism

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: Placebo supplement
Dietary supplement: Placebo supplements
Participants will receive placebo supplements each day for 12 weeks.
Active Comparator: Zinc supplement
Dietary supplement: Zinc supplements
Participants will receive 40 mg of zinc each day for 12 weeks.
Dietary supplement: Placebo supplements
Participants will receive placebo supplements each day for 12 weeks.
Active Comparator: Omega 3 supplement
Dietary supplement: Placebo supplements
Participants will receive placebo supplements each day for 12 weeks.
Dietary supplement: Omega 3 supplements
Participants will receive 2 g of omega 3 fatty acids each day for 12 weeks.
Active Comparator: Zinc and omega 3 supplements
Dietary supplement: Zinc supplements
Participants will receive 40 mg of zinc each day for 12 weeks.
Dietary supplement: Omega 3 supplements
Participants will receive 2 g of omega 3 fatty acids each day for 12 weeks.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Plasma lipids (total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides)
Time Frame: 12 weeks
12 weeks
Glycaemic control (glucose, insulin, HbA1c)
Time Frame: 12 weeks
12 weeks
Inflammation & oxidative stress (CRP, TNF-α, IL-1, IL-2, IL-6, IL-10 F2 isoprostanes, NF-κB, MPO, other)
Time Frame: 12 weeks
12 weeks

Secondary Outcome Measures

Outcome Measure
Time Frame
Zinc transporter mRNA expression in peripheral blood mononuclear cells
Time Frame: 12 weeks
12 weeks
Plasma zinc
Time Frame: 12 weeks
12 weeks
Plasma fatty acids
Time Frame: 12 weeks
12 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Sydney

Investigators

  • Principal Investigator: Samir Samman, University of Sydney
  • Principal Investigator: Meika Foster, University of Sydney

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

July 1, 2010

Primary Completion (Actual)

December 1, 2011

Study Completion (Actual)

December 1, 2011

Study Registration Dates

First Submitted

October 25, 2011

First Submitted That Met QC Criteria

January 5, 2012

First Posted (Estimate)

January 9, 2012

Study Record Updates

Last Update Posted (Estimate)

January 9, 2012

Last Update Submitted That Met QC Criteria

January 5, 2012

Last Verified

January 1, 2012

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • HREC 12392

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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