The Effect of Dietary Sitosterol on Blood Sugar and Cholesterol

Completed · Not applicable

Conditions studied: Sitosterolemia

In brief

This study will determine if dietary supplements of sitosterol (a plant cholesterol commonly found in vegetables) can modify blood sugar and cholesterol levels and reduce the stiffness of the blood vessels in people with an abnormal copy of a gene that causes sitosterolemia. People who carry only one copy of the abnormal gene are healthy but have increased blood levels of sitosterol. People with two abnormal copies of the gene have increased levels of sitosterol and have an increased risk of heart attack. This condition is called sitosterolemia. Although extremely rare in the general population, up to 4% of the Amish carry an abnormal copy of this gene. People of Amish background who are 18 years of age or older and in whom one person carries one copy of the abnormal gene that causes sitosterolemia and the other does not have an abnormal gene may be eligible for this study. Subjects must be of the same sex and within 5 years of age of each other. During two periods of one month each participants receive pills containing sitosterol and then a special diet and meal supplements to change the levels of sitosterol in the diet. During only one of the two study periods, subjects receive sitosterol supplements in the pills for one month and then for 10 days in the diet. At the end of each study period, subjects come to the NIH Clinical Center for one day for the following tests: * Measurements of height, weight, blood pressure and heart rate. * Adipose (fat) tissue biopsy. A small piece of fat from under the skin of the abdomen is removed to examine how sitosterol affects fat tissue and its ability to process sugar and fat. * Indirect calorimetry. A plastic transparent hood is placed over the subject s head to collect the air that is breathed for about one-half hour to study how the body uses sugar to generate energy. * Endothelial vascular function. An ultrasound picture of a blood vessel in the forearm is taken and a blood pressure cuff is inflated around the arm to measure the vessel s ability to stretch. * Intravenous glucose tolerance test: A small plastic tube is placed in a vein in each arm. Then over one minute the subject receives glucose through one of the tubes. Twenty minutes later the subject is given a small amount of insulin through the same tube. Blood samples are drawn through the tube in the other arm at frequent intervals for 3 hours. This test measures how sitosterol affects how the body processes sugar. * DEXA scan. The subject lies on an x-ray table for 20 minutes during the scan, which measures total body fat.

Key facts

Study ID: NCT00531128
Run by: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
People needed: 14
Starts: 2007-09-10
Expected to finish: 2018-05-17
Last updated by the study team: 2018-05-21

Who can join

Age: 18 and older. Sex: any. Healthy volunteers: not accepted.

You may not qualify if…

BMI greater than or equal to 40 kg/m(2)
History or symptoms compatible with cardiovascular disease, including hypertension greater than or equal to 140/90 mm Hg or current therapy for hypertension or cardiovascular disease
Allergy to lidocaine, acetaminophen with codeine, oxycodone.
Pregnancy
Breastfeeding
Use of hormonal contraceptives or estrogen replacement therapy
Diabetes mellitus, either type 1 or 2
Hypercholesterolemia (serum levels greater than or equal to 240 mg/dL), and/or use of antilipemic therapy
Liver disease or ALT serum level greater than two fold the upper laboratory reference limit
Renal insufficiency or estimated creatinine clearance less than or equal to 50 mL/min
Use of medications/dietary supplements/alternative therapies known or thought to alter lipid or carbohydrate metabolism (e.g. omega-3 fatty acids, chromium, vanadate) during the study
Current history or symptoms compatible with psychosis including major depression (including history of hospitalization for depression, history of attempted suicide, history of suicidal ideation), and/or use of antipsychotic medications
History of drug or alcohol abuse within the last 5 years; current use of drugs or alcohol (CAGE greater than 3)
Keloid formation (relative to subcutaneous adipose tissue biopsy)

Where it is running

National Institutes of Health Clinical Center, 9000 Rockville Pike — Bethesda, Maryland, United States
University of Maryland Amish Research — Lancaster, Pennsylvania, United States

Full record on ClinicalTrials.gov

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