Clinical trial NCT01541592: Does Class of Dietary Fat Affect Insulin Resistance?
Official title: Insulin Resistance and Dietary Fat
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Insulin Resistance
Keywords: Insulin resistance
Endothelial dysfunction
saturated fat
monounsaturated fat
polyunsaturated fat
Lead sponsor: Mayo Clinic
Sponsor class: OTHER
First posted: 2012-03-01
Enrollment: 24
Sex: ALL
Minimum age (years): 18
Maximum age (years): 40
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: BASIC_SCIENCE

Brief summary: It has been shown that intravenous fatty acids given to normal volunteers in the form of heparin and lipid emulsions will cause insulin resistance in a matter of a few hours. It is not known if this same phenomenon can be demonstrated with oral fat. The investigators are specifically interested in whether or not there are differences in the induction of insulin resistance between the 3 main classes of fatty acids (saturated, monounsaturated and polyunsaturated).

The investigators also plan to evaluate endothelial dysfunction and blood pressure; both of which frequently accompany insulin resistance.

Detailed description: Type 2 Diabetes and cardiovascular disease are closely linked. A common abnormality in both conditions is insulin resistance. The primary cause of insulin resistance in not known. A significant question is what dietary components contribute to the development of insulin resistance. Based on epidemiologic data, it seems that the type of dietary fat is a significant contributor to the development of insulin resistance. However, some researchers argue that the main determinant is total amount of fat, not the composition.

This study is intended to determine if the main types of fat (saturated, monounsaturated and polyunsaturated) ingested over a short time can cause insulin resistance in lean, healthy people. It has been demonstrated that 6 hours of intravenous fat infused into lean, healthy subjects can result in insulin resistance, as well as blood pressure elevation and endothelial dysfunction. Whether this is so with oral fat is not known. The question is important because there is debate about whether the type of fat is as important as the quantity of fat in a person's daily diet. Settling this debate will enhance the ability of health care personnel to determine the optimal dietary recommendations.

This study will make use of a high fat diet consisting of vegetable oils high in the 3 main fatty acids in plasma (palmitate, oleate and linoleate). Because large fat loads can cause intestinal discomfort, a feeding tube will be used to bypass the stomach. The 3 oils will be assigned randomly following a base line study with saline 2 weeks prior to the intervention. Our primary endpoint is insulin resistance, which will be measured by a euglycemic, hyperinsulinemic clamp. Secondary measures will include changes in blood pressure and in vascular reactivity as measured by ultrasound after brief occlusion of a forearm vessel. The changes will be compared to baseline and to the other 2 groups.

Eligibility criteria: Inclusion Criteria:

* Lean,healthy adults 18 - 40
* No chronic medications (birth control pills allowed)
* Weight stable
* Normal fasting labs performed at screening
* Body mass index ≤ 25 kg/M\^2 .

Exclusion Criteria:

* Insulin dependent diabetes
* Thyroid disease
* History of diabetes or heart disease
* History of type 2 diabetes in parent or sibling

Primary outcomes:
measure: Change in Insulin Sensitivity from Baseline at Two Weeks
timeFrame: Average of 2 weeks.
Secondary outcomes:
measure: Change in Endothelial Function from Baseline at Two Weeks
timeFrame: Average of two weeks
measure: Change in Systolic Blood Pressure at Two Weeks
timeFrame: Average of two weeks
Other outcomes:
Locations:
city: Rochester
country: United States
facility: Mayo Clinic in Rochester
state: Minnesota
Study officials:
affiliation: Mayo Clinic
name: Robert Nelson, MD
role: PRINCIPAL_INVESTIGATOR
References: