Can a Modified Fat Diet With Low Glycaemic Load Improve Insulin Sensitivity and Inflammatory Mediators in Overweight People With Chronic Heart Failure?

July 31, 2007 updated by: Bayside Health

This study is looking at overweight patients with chronic heart failure (CHF), to compare the effects of a modified fat diet with a reduced glycaemic load (diet 1); and a conventional low fat, high carbohydrate diet (diet 2) on:

  • insulin sensitivity (using the homeostasis model assessment [HOMA] model)
  • lipid profile
  • symptomatic status (6 minute walk distance and Heart Failure Quality of Life [HF QOL] Questionnaire)
  • body weight
  • inflammatory mediators (tumor necrosis factor [TNF] alpha, C-reactive protein [CRP], interleukin-6 [IL-6])

The hypotheses of this study are:

  • Diet 1 will be associated with lower insulin resistance than diet 2.
  • The lipid profile will be better in CHF patients on diet 1 than on diet 2.
  • Patients on diet 1 will have a better symptomatic status than patients on diet 2.
  • Diet 1 will maintain body weight in patients with CHF as well as diet 2.
  • Diet 1 will suppress the expression of TNF-alpha, CRP and IL-6 more than diet 2.

Study Overview

Status

Unknown

Conditions

Intervention / Treatment

Detailed Description

There is an increasing prevalence of chronic heart failure (CHF) in Western societies. In the last decade, progress has been made in understanding the neurohormonal involvement in the progression of the disease and consequently, new treatments have been developed although the mortality rate still remains high. Chronic heart failure is associated with marked insulin resistance as well as increasing plasma levels of pro-inflammatory markers such as Tumor Necrosis Factor-alpha (TNF-alpha) and Interleukin-6 (IL-6) with increasing severity of the disease. This has recently become an area of increased research interest. In CHF, insulin resistance may be present even when blood glucose levels appear normal. Independently of its influence on risk of arteriosclerosis, insulin resistance supports further progression of heart failure. Hyperinsulinaemia has also been found to worsen symptomatic status in CHF patients.

The introduction of beta-blockers in the treatment of CHF may have a beneficial effect on insulin resistance. However, so far tested drugs seem to have little influence on production of pro-inflammatory markers in CHF patients. The use of beta-blockers in the clinical setting is also associated with weight gain. While weight gain is of benefit to patients with cachexia, a common problem in CHF, it is problematic in CHF patients who are already overweight, particularly since obesity is known to be implicated in the development of insulin resistance. Because of this, it would seem to be beneficial to prevent further weight gain in those patients with heart failure who are not cachexic. Weight loss in these patients, however should also be prevented since obese patients with CHF appear to have the better prognosis. As change in body weight has important implications for disease progression, choice of dietary treatment is of particular importance in CHF patients. Ideally in CHF patients, we should be maintaining body weight while still attempting to reduce other coronary risk factors such as insulin resistance and atherogenic dyslipidemia.

Traditionally, diet for people with insulin resistance and other features of the metabolic syndrome has been based on a low fat, high carbohydrate dietary prescription. This has been questioned recently with emerging clear endorsement of diets that are restricted in saturated fat (< 10% of total energy [%E]) but by allowing higher amounts of monounsaturated fat (MUFA), also reduce the diet carbohydrate content and thus the glycaemic load. Metabolic studies in people with diabetes have shown that modified fat (high MUFA) diets are more effective than a low fat high carbohydrate diet in improving insulin resistance although no similar studies are yet available for people with heart failure.

Studies in people with diabetes have also indicated that modified fat (high MUFA) diets are clearly more beneficial than low fat diets in the effects on triacylglycerols and HDL cholesterol and they also favorably influence blood pressure, coagulation, endothelial activation, inflammation, and thermogenic capacity. Modified fat (high MUFA) diets therefore reduce heart disease risk. Moreover, when the energy density is controlled through inclusion of plenty of fruit and vegetables, modified fat (high MUFA) diets do not promote obesity. One final benefit is better acceptance and compliance long term.

Study Type

Interventional

Enrollment (Anticipated)

50

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
    • Victoria
      • Melbourne, Victoria, Australia, 3004
        • Recruiting
        • Alfred Hospital
        • Contact:
        • Contact:
        • Principal Investigator:
          • Fiona J Adams, BSc. Grad Dip Diet

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

18 years to 75 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • English speaking heart failure patients (New York Heart Association [NYHA] Classes 1 - 3) attending the Alfred Hospital outpatient clinic will be enrolled.

Exclusion Criteria:

  • Patients will be excluded if they are below the healthy weight range (BMI < 25 kg/m2) or if they are morbidly obese (BMI > 35 kg/m2).
  • Patients with heart failure NYHA Class 4 will be excluded due to their increased risk of developing cachexia.

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

  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Body mass index (BMI)
Blood lipids
Inflammatory mediators
HOMA

Secondary Outcome Measures

Outcome Measure
Heart Failure Quality of Life Questionnaire
6 minute walk test

Collaborators and Investigators

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

Sponsor

Bayside Health

Investigators

  • Principal Investigator: Fiona J Adams, BSc. Grad Dip Diet, Dietition on Staff, Alfred Hospital

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

January 1, 2005

Study Registration Dates

First Submitted

September 13, 2005

First Submitted That Met QC Criteria

September 13, 2005

First Posted (Estimate)

September 14, 2005

Study Record Updates

Last Update Posted (Estimate)

August 1, 2007

Last Update Submitted That Met QC Criteria

July 31, 2007

Last Verified

September 1, 2005

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 12/05
  • Small Project Grant - T10513
  • Allied Health Grant - A10501

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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