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Niacin, N-3 Fatty Acids and Insulin Resistance

This study has been completed.
Information provided by:
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) Identifier:
First received: February 2, 2006
Last updated: April 30, 2013
Last verified: April 2013
This research study is being conducted to test the effects of two drugs on blood lipids (cholesterol and triglycerides) and blood sugar (glucose) levels in patients with diabetes or "pre-diabetes" (both of which have a condition called "insulin-resistance"). These products are Niaspan (extended release nicotinic acid) and Omacor (omega-3 acid ethyl esters). We hypothesize that the combination of Niaspan and Omacor will reduce serum triglyceride levels, increase HDL-cholesterol levels and do so without altering glucose levels.

Condition Intervention Phase
Metabolic Syndrome Hypertriglyceridemia Drug: omega-3 acid ethyl esters Drug: extended release niacin Drug: placebo Drug: combined treatment Phase 4

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Niacin, N-3 Fatty Acids and Insulin Resistance

Resource links provided by NLM:

Further study details as provided by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK):

Primary Outcome Measures:
  • Serum TG and HDL-C [ Time Frame: baseline and 4 months ]

Secondary Outcome Measures:
  • Insulin sensitivity, postprandial triglyceridemia, peripheral arterial tonometry [ Time Frame: baseline and 4 months ]

Enrollment: 10
Study Start Date: October 2007
Study Completion Date: December 2008
Primary Completion Date: August 2008 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Placebo Comparator: 1
Dual placebo
Drug: placebo
omacor placebo plus niaspan placebo
Experimental: 2
Drug: extended release niacin
2 g qpm
Other Name: niaspan
Experimental: 3
Drug: omega-3 acid ethyl esters
4 q qd
Other Name: lovaza omacor
Drug: omega-3 acid ethyl esters
4 g qd
Other Name: lovaza omacor
Experimental: 4
combined therapy
Drug: combined treatment
omega-3 acid ethyl esters 4 g qd and extended release niacin, titrate up to 2 g Qpm
Other Names:
  • lovaza, omacor
  • niaspan

  Hide Detailed Description

Detailed Description:

The insulin resistance syndrome (IRS) afflicts approximately 25% of the US adult population. Its principal components include some or all of the following: central obesity, elevated triglyceride levels, decreased high density lipoprotein cholesterol (HDL-C) levels, a preponderance of small, dense low density lipoprotein (LDL) particles, hyperglycemia, hypertension, and increased thrombotic tendency. Subjects with the IRS are at increased risk for type 2 diabetes and/or coronary heart disease (CHD). While lifestyle changes (diet and exercise) often improve many of the manifestations of the IRS, pharmacotherapy is often needed to normalize individual components.

In recent studies from our laboratory, niacin and fish oil (n-3 fatty acids, FA) used in combination in insulin resistant individuals led to an expected improved the lipid phenotype (reduced triglycerides, increased HDL-C, and fewer, small, dense LDL particles). What was not expected, however, was that an important marker of adipose tissue insulin resistance - meal-induced suppression of free fatty acid (FFA) flux - would be improved as well. Further, knowing that these agents (given as monotherapy) have been reported to worsen glycemia in diabetic subjects, we were surprised to find no significant deterioration in glycemic control. Further preliminary studies in patients with poorly-controlled type 2 diabetes confirmed the ability of this combination of over-the-counter natural agents to significantly improve the lipid profile without adverse effects on glycemia.

Our working hypothesis is that excessive FFA flux from adipose tissue raises serum triglyceride concentrations and leads to other manifestations of the IRS. FFA flux is chronically elevated in insulin resistant subjects due to the insensitivity (i.e., resistance) of their adipocytes to the anti-lipolytic effects of insulin. Released FFA (especially from visceral adipose depots) stimulate hepatic triglyceride synthesis, leading to elevated serum triglyceride levels which subsequently contribute to reduced HDL-C and increased small, dense LDL concentrations. In addition, a high FFA flux can interfere with whole body glucose disposal. If this hypothesis is true, then interventions that improve adipocyte insulin sensitivity may be expected to improve a spectrum of risk factors associated with the insulin resistant state.

Since our preliminary studies support this hypothesis, we propose the following four specific aims which will be tested in a 4-arm, randomized, placebo-controlled, double blind trial:

Specific Aim 1. To test the hypothesis that n-3 FA and niacin (given singly and in combination) will enhance insulin-mediated suppression of FFA rate of appearance (Ra; a surrogate for adipose tissue insulin sensitivity) in insulin resistant subjects.

Specific Aim 2. To test the hypothesis that n-3 FA and niacin (given singly and in combination) will improve insulin sensitivity in insulin resistant subjects.

Specific Aim 3. To test the hypothesis that n-3 FA and niacin (given singly and in combination) will reduce VLDL-triglyceride production rates in insulin resistant subjects.

Specific Aim 4. To test the hypothesis that n-3 FA and niacin (given singly and in combination) will improve the dyslipidemic profile (i.e., reduce serum triglyceride and small, dense LDL concentrations and elevate HDL-C concentrations) in insulin resistant subjects.

At the completion of these studies, we expect to have detailed information on the potential therapeutic efficacy and the kinetic mechanism of action of combined treatment with n-3 FA and niacin. A better understanding of the action of these agents should lead to a clearer appreciation of the relationship between FFA flux and insulin resistance, to more effective therapy for the dyslipidemia of insulin resistance and ultimately to reduced risk for CAD in this burgeoning patient population.


Ages Eligible for Study:   40 Years to 69 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

40 and 69 years of age Male or female (without hormonal cycling as described below) BMI > 25 Fasting serum triglycerides > 150 mg/dL Ratio of TG/HDL-C > 3.5

Exclusion Criteria:

BMIs > 40 kg/m2 TG > 750 mg/dL HDL-C < 10 mg/dL Presence of other secondary causes of dyslipidemia or hyperglycemia such as hepatic, renal, thyroid or other endocrine diseases History of hypersensitivity to niacin or fish oils History of gout, hepatitis, peptic ulcer or cardiovascular disease Presence of diabetes mellitus, whether controlled by diet or drugs. (We will eliminate subjects with undiagnosed diabetes by screening for fasting glucose > 126 mg/dL) Use of any dietary supplements providing more than 50 mg of niacin or 100 mg of n-3 FA Use of any herbal preparations or weight-loss products Taking any lipid-lowering drugs for at least four weeks prior to screening for the study Medically-required treatment with nitrates, calcium channel blockers, or adrenergic blocking agents (per the Niaspan package insert) Hemoglobin < 12 g/dL (owing to the significant amount of blood being drawn) LDL-C > 145 mg/dL. (This restriction will prevent the randomization of any subject whose LDL-C levels, if assigned to an n-3 FA group, might rise by 10% and thus exceed 160 mg/dL) Known substance abuse Participation in a clinical drug trial anytime during the 30 days prior to screening Anyone whom the investigators judge to be a poor candidate

  Contacts and Locations
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Please refer to this study by its identifier: NCT00286234

United States, South Dakota
Sanford Clinic Clinical Research Services
Sioux Falls, South Dakota, United States, 57105
Sponsors and Collaborators
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Principal Investigator: William S Harris, PhD Sanford Research/USD
  More Information

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: William S. Harris, Sanford Research/USD Identifier: NCT00286234     History of Changes
Other Study ID Numbers: DK61486 (completed)
Study First Received: February 2, 2006
Last Updated: April 30, 2013

Keywords provided by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK):
insulin resistance
omega-3 fatty acids

Additional relevant MeSH terms:
Metabolic Syndrome X
Insulin Resistance
Glucose Metabolism Disorders
Metabolic Diseases
Lipid Metabolism Disorders
Nicotinic Acids
Hypoglycemic Agents
Physiological Effects of Drugs
Hypolipidemic Agents
Molecular Mechanisms of Pharmacological Action
Lipid Regulating Agents
Vasodilator Agents
Vitamin B Complex
Growth Substances processed this record on August 16, 2017