Clinical trial NCT01241474: Effect of Fish Oil on Insulin Sensitivity
Official title: Chronic Long-chain n-3 PUFA Supplement and Insulin Action in Human Subjects With Impaired Glucose Regulation
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Metabolic Syndrome X
Type 2 Diabetes Mellitus
Sarcopenia
Lead sponsor: University of Aberdeen
Sponsor class: OTHER
First posted: 2010-11-16
Enrollment: 34
Sex: ALL
Minimum age (years): 40
Maximum age (years): 69
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: PREVENTION

Brief summary: 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.

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.

Eligibility criteria: 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

Primary outcomes:
measure: Change in insulin sensitivity assessed by hyperinsulinemic-euglycemic-eu-aminoacidemic clamp
timeFrame: 0 months and 9 months
Secondary outcomes:
measure: Change in amount of docosahexaenoic acid and eicosapentaenoic acid incorporated into phospholipid fraction of red blood cell membranes
timeFrame: at monthly intervals between 0 and 9 months
measure: Change in plasma inflammatory markers
timeFrame: 0, 4 and 9 months
Other outcomes:
Locations:
city: Aberdeen
country: United Kingdom
facility: Rowett Institute of Nutrition and Health, University of Aberdeen
Study officials:
affiliation: Rowett Institute of Nutrition and Health, University of Aberdeen
name: Gerald E Lobley, BSc PhD
role: PRINCIPAL_INVESTIGATOR
References: