Effect of Fish Oil on Insulin Sensitivity

Chronic Long-chain n-3 PUFA Supplement and Insulin Action in Human Subjects With Impaired Glucose Regulation

The purpose of this study is to determine whether a prolonged (9 month) high (6g/d) of marine oil improves insulin sensitivity and glucose control in subjects with impaired glucose regulation.

Study Overview

• Status: Completed
• Conditions: Type 2 Diabetes Mellitus; Sarcopenia; Metabolic Syndrome X
• Intervention / Treatment: Dietary supplement: EPAX 6000 (marine omega 3 EPA/DHA fatty acid concentrates; Dietary supplement: Maize (corn) oil

Detailed Description

The incidence of Type 2 diabetes is related both to age and obesity. The disease impacts on quality of life and treatments represent a major health cost. Prevention or delayed onset of the disease remains a key target. Animal studies have shown that provision of high amounts of fish oil in the diet improves insulin sensitivity but human trials have proved equivocal. Recent dose-response trials in animals have shown the improved insulin sensitivity only occurs when the proportion of n-3 long chain polyunsaturated fatty acids (n-3 PUFA), docosahexaenoic acid and eicosapentaenoic acid, exceeds 14% of the total phospholipid fraction within tissue cell membranes. To achieve such values in humans would require a high dose of n-3 PUFA supplied over a prolonged period of time. This is tested within the current study where a daily dose of 6 g day of fish oil (containing a total of 3g docosahexaenoic acid plus eicosapentaenoic acid) is supplied for 9 months. As well as improving control of glycemia increased insulin sensitivity may also enhance protein metabolism and reduce the impact of frailty in older subjects.

• Study Type: Interventional
• Enrollment (Actual): 34
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • Aberdeen, United Kingdom, AB21 9SB
    • Rowett Institute of Nutrition and Health, University of Aberdeen

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 40 years to 69 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Men and post-menopausal women aged 40-65 years
• Recruited from the surrounding community of Aberdeen

• Insulin resistance with either

  1. venous plasma fasting glucose > 5.0, < 7.0 mmo/l,
  2. venous plasma 2-h 75-g OGTT > 5.0, < 11.1 mmol/l
  3. newly diagnosed with type 2 diabetes; must be asymptomatic and detected during our screenings and not require oral hypoglycemic or insulin therapy, HbA1c < 7.0%

Exclusion Criteria:

• Diabetes requiring oral hypoglycemic therapy or insulin
• Treatment with anticoagulants, regular steroids or non-steroidal anti-inflammatory drug treatment, tricyclic antidepressants, anti-arrhythmics
• Hepatic failure
• Renal failure
• Significant respiratory disease
• Anaemia
• Cardiovascular disease
• Malignancy
• Thromboembolic or coagulation disorders
• Alcoholism or other substance misuse
• Eating disorders or significant psychiatric disorders

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Fish oil	Dietary supplement: EPAX 6000 (marine omega 3 EPA/DHA fatty acid concentrates; 6 x 1g capsules per day of marine oil (contains 3g/d docosahexaenoic acid plus eicosapentaenoic acid) for a 9 month period; Other Names: EPAX 6000TG code F0-5222/XT
Placebo Comparator: Maize (corn) oil	Dietary supplement: Maize (corn) oil; 6 x 1g capsules per day for 9 months; Other Names: Banner chemicals product GL-518/XT

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Change in insulin sensitivity assessed by hyperinsulinemic-euglycemic-eu-aminoacidemic clamp	0 months and 9 months

Secondary Outcome Measures

Outcome Measure	Time Frame
Change in amount of docosahexaenoic acid and eicosapentaenoic acid incorporated into phospholipid fraction of red blood cell membranes	at monthly intervals between 0 and 9 months
Change in plasma inflammatory markers	0, 4 and 9 months

Collaborators and Investigators

• Sponsor: University of Aberdeen
• Investigators: Principal Investigator: Gerald E Lobley, BSc PhD, Rowett Institute of Nutrition and Health, University of Aberdeen

Study record dates

Study Major Dates

• Study Start: February 1, 2009
• Primary Completion (Actual): June 1, 2012
• Study Completion (Actual): June 1, 2012

Study Registration Dates

• First Submitted: November 10, 2010
• First Submitted That Met QC Criteria: November 12, 2010
• First Posted (Estimate): November 16, 2010

Study Record Updates

• Last Update Posted (Estimate): August 7, 2012
• Last Update Submitted That Met QC Criteria: August 6, 2012
• Last Verified: August 1, 2012

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Glucose Metabolism Disorders; Metabolic Diseases; Nervous System Diseases; Neurologic Manifestations; Endocrine System Diseases; Diabetes Mellitus; Neuromuscular Manifestations; Pathological Conditions, Anatomical; Insulin Resistance; Hyperinsulinism; Muscular Atrophy; Atrophy; Diabetes Mellitus, Type 2; Metabolic Syndrome; Sarcopenia
• Other Study ID Numbers: UofAberdeen RINH HNU800