Effects of Low and Moderate Fat Diets on Lipids, Inflammation and Vascular Reactivity in the Metabolic Syndrome
NCT ID: NCT00362908
Last Updated: 2010-10-28
Study Results
The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.
Basic Information
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COMPLETED
NA
71 participants
INTERVENTIONAL
2006-09-30
2010-06-30
Brief Summary
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Detailed Description
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During the initial screening period, participants follow an American Heart Association (AHA) Step 1 diet and cholesterol levels are tested for eligibility under the criteria of the Metabolic Syndrome. Before being randomized, eligible participants have a frequently sampled intravenous glucose tolerance test (FSIVGTT), an abdominal CT scan to measure fat content in two locations and two brachial artery reactivity tests. The FSIVGTT provides information about whether participants are insulin sensitive or insulin resistant. The CT scan measures the fat content in the abdomen and the liver. The brachial artery reactivity tests measure blood flow through the brachial artery in the arm.
This 7-month study consists of two 1-month feeding periods, a rest month between the two feeding periods and a 4-month follow-up diet in a free-living setting. In Month 1, participants are randomly assigned to follow either a moderate fat, moderate carbohydrate diet or a low fat, high carbohydrate diet. Participants receive prepared food at study visits twice a week. Weight and vital signs are measured at each study visit, and blood is collected at baseline, and Weeks 3-1/2 and 4. A brachial artery reactivity test, using an ultrasound to measure artery size and blood flow in the arm, is performed twice in Week 4. In the Month 2 rest period, participants follow an AHA Step 1 diet at home. In Month 3, participants switch to the other diet and all study procedures and evaluations are repeated as in Month 1. During the following Months 4 through 7, participants continue following the second assigned diet, but are responsible for preparing their own food. They meet with a dietician once a week for 1 month to learn how to prepare meals at home. During this 4-month period, blood collection, vital sign measurements, and review of medical history and diet continue at monthly visits. At the end of Month 7, participants again undergo two brachial artery reactivity tests.
As of October, 2010, 148 were screened with 71 eligible to be randomized. Seven discontinued prior to completion and 64 completed the 7 month study. The intervention is complete and analyses are ongoing.
Conditions
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Study Design
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RANDOMIZED
CROSSOVER
TREATMENT
DOUBLE
Study Groups
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Group 1
Subjects consume study diets in the following order:
1. Diet 1 (20% fat diet) for 1 month with all food provided,
2. American Heart Association Step I Diet for 1 month at home, and
3. Diet 2 (40% fat diet) for 1 month with all food provided and then continue to follow this diet for an additional 4 months at home.
Moderate Fat and Moderate Carbohydrate Diet
40% allowable fat diet (less than or equal to 7% saturated fat) consumed for 1 or 5 months
Low Fat and High Carbohydrate Diet
20% fat diet (less than or equal to 7% saturated fat) consumed for 1 or 5 months
Group 2
Subjects consume study diets in the following order:
1. Diet 2 (40% fat diet) for 1 month with all food provided,
2. American Heart Association Step I Diet for 1 month at home, and
3. Diet 1 (20% fat diet) for 1 month with all food provided and then continue to follow this diet for an additional 4 months at home.
Moderate Fat and Moderate Carbohydrate Diet
40% allowable fat diet (less than or equal to 7% saturated fat) consumed for 1 or 5 months
Low Fat and High Carbohydrate Diet
20% fat diet (less than or equal to 7% saturated fat) consumed for 1 or 5 months
Interventions
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Moderate Fat and Moderate Carbohydrate Diet
40% allowable fat diet (less than or equal to 7% saturated fat) consumed for 1 or 5 months
Low Fat and High Carbohydrate Diet
20% fat diet (less than or equal to 7% saturated fat) consumed for 1 or 5 months
Eligibility Criteria
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Inclusion Criteria
1. Abdominal obesity greater than 90 cm in Asian men, greater than 102 cm in all other men, greater than 80 cm in Asian women, and greater than 88 cm in all other women
2. Triglycerides greater than or equal to 150 mg/dL at two screening visits (Required for the purposes of this study, which focuses on the dyslipidemic phenotype)
3. HDL cholesterol levels less than 40 mg/dL in men and less than 50 mg/dL in women
4. Blood pressure levels greater than 130/85 mmHg or taking an allowed blood pressure medication at Visit 1 (see definition in exclusions below)
5. Fasting glucose greater than or equal to 100mg/dL at Visit 1
Exclusion Criteria
* Triglycerides greater than 500mg/dL at Visit 1
* Blood pressure over a mean of 150/95 at the two first visits
* Body mass index greater than 40 kg/m²
* Currently taking any lipid lowering medication other than statins
* Currently taking high doses of thiazide diuretics (greater than 50mg/day), or any other blood pressure medication in the past 4 weeks
* Use of plant sterols from sources such as Benecol or Take Control margarines in the past 4 weeks
* Use of any fish oil supplements in the week prior to screening
* Blood glucose greater than 140 mg/dL or use of diabetes medications
* Hospitalization for coronary disease in the last 6 months
* Use of nitroglycerin or other nitrates
* Unstable liver, renal, gastrointestinal or pulmonary disease or mental disease, or medically unstable for other reasons
* Alcohol intake greater than 2 drinks/day, any illegal drug use, smoking, chronic NSAID use or NSAID use within 5 days before the BAR study
* Pregnancy intended within one year or one year prior or currently lactating
* In reproductive age women, an irregular menstrual cycle (must have consistent menstrual cycle between 24 to 32 days)
* Use or expectation of use of oral or patch contraceptive
* Unable or unlikely to be able to comply with study requirements
30 Years
75 Years
ALL
Yes
Sponsors
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National Heart, Lung, and Blood Institute (NHLBI)
NIH
University of Washington
OTHER
Responsible Party
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University of Washington
Principal Investigators
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Pathmaja Paramsothy, MD
Role: PRINCIPAL_INVESTIGATOR
University of Washington
Locations
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Northwest Lipid Research Clinic
Seattle, Washington, United States
Countries
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References
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Knopp RH, Fish B, Dowdy A, Retzlaff B, Walden C, Rusanu I, Paramsothy P. A moderate-fat diet for combined hyperlipidemia and metabolic syndrome. Curr Atheroscler Rep. 2006 Nov;8(6):492-500. doi: 10.1007/s11883-006-0025-9.
Paramsothy P, Krieger E, Chan E, Fish B, Dowdy A, Knopp RH. Abstract 1017: Moderate vs Low Fat Diet Effects on Lipids and Inflammation in Metabolic Syndrome. Circulation, Nov 2009; 120: S426. Presented as oral abstract at AHA Annual Scientific Session November, 2009.
Paramsothy P, Kreiger E, Chan E, Preus E, Rusanu I, Prager S, Knopp RH. Effects Of Low Fat Vs. Moderate Fat Diet On Insulin Resistance And Endothelial Function In Metabolic Syndrome. J. Am. Coll. Cardiol., March 9, 2010; 55: A58.E555. Presented as poster at ACC, Atlanta, GA. 3/10.
Other Identifiers
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422
Identifier Type: -
Identifier Source: secondary_id
29854-B
Identifier Type: -
Identifier Source: org_study_id