Effect of Dietary Amino Acid Profile on Lipoprotein Metabolism, Vascular Reactivity and Inflammatory Markers

This study has been completed.
Sponsor:
Information provided by (Responsible Party):
Tufts University
ClinicalTrials.gov Identifier:
NCT00175084
First received: September 8, 2005
Last updated: May 21, 2014
Last verified: May 2014
  Purpose

The aim of this study is to explore the significance of the Lys:Arg ratio on responses of lipids and lipoprotein concentrations to dietary proteins and to evaluate the effects of dietary Lys:Arg on cardiovascular disease risk factors and endothelial function.


Condition Intervention
Hyperlipidemias
Metabolic Syndrome X
Cardiovascular Diseases
Behavioral: Comparison of dietary protein amino acid profile

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single Blind (Investigator)
Primary Purpose: Prevention
Official Title: Effect of Dietary Amino Acid Profile on Lipoprotein Metabolism, Vascular Reactivity and Inflammatory Markers

Resource links provided by NLM:


Further study details as provided by Tufts University:

Primary Outcome Measures:
  • Serum lipid and lipoprotein concentrations, endothelial function, blood pressure, indicators of nitrous oxide end products, homocysteine, inflammation and oxidation markers. [ Time Frame: 5 week ] [ Designated as safety issue: No ]

Estimated Enrollment: 30
Study Start Date: October 2004
Study Completion Date: December 2012
Primary Completion Date: June 2007 (Final data collection date for primary outcome measure)
Intervention Details:
    Behavioral: Comparison of dietary protein amino acid profile
    Healthy adults over 50 years of age (men and postmenopausal women) will be assigned to one of two diets differing in lysine to arginine ration (0.7 vs. 1.4) for a 5 week period and then switched to the alternate diet, with a 2 to 4-week washout period, in a randomized crossover design. Blood samples will be collected three times in the fasted state and once 4-hours after the evening meal during the last week of each dietary period of measurement of concentration of plasma lipids, lipoproteins, apolipoproteins, arginine, C-reactive protein, nitrites/nitrates, homocysteine, lecithin-cholesterol acetyltransferase (LCAT), cholesteryl ester transfer protein (CETP), and LDL-receptor messenger ribonucleic acid (mRNA) expression.A 24-hour urine sample will be collected at the end of each phase to measure F2-isoprostanes as an indicator of whole body oxidation.
Detailed Description:

Findings from early studies in a variety of experimental models of atherosclerosis on the effect of dietary protein suggested that proteins from vegetable sources are less cholesterolemic and atherogenic than proteins from animal sources. Throughout the later part of the 20th century there has been sporadic interest in the effect of protein type and amino acid profiles on blood lipid concentrations and atherosclerosis. A major focus for this evaluation has been to compare proteins based on their amino acid profile, often expressed as lysine (Lys) to arginine (Arg) ratio (Lys:Arg). While animal studies have provided important information regarding the significance of the Lys:Arg in determining the cholesterolemic response to a dietary protein, interpretation of these data must be done with caution since most of the studies have been conducted in animal models that have a different lipoprotein distribution and metabolism than humans. Moreover, the mechanistic insights of this response are yet to be determined. While the favorable effects of Arg on endothelial function appear to be consistent when Arg is administered using a supplement, the effects of dietary Arg naturally present in protein rich foods has yet to be determined. The aim of this proposal is to explore the significance of the Lys:Arg ratio on responses of lipids and lipoprotein concentrations to dietary proteins and to evaluate the effects of dietary Lys:Arg on cardiovascular disease risk factors and endothelial function.

  Eligibility

Ages Eligible for Study:   50 Years to 85 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Age: 50-85 years
  • LDL-C concentrations >120 mg/dL

Exclusion Criteria:

  • Use of medications known to affect lipid metabolism
  • Established cardiovascular disease
  • Renal disease
  • Liver disease
  • Thyroid disease unless controlled with medication for at least 6 months
  • Type I and II diabetes
  • Irritable bowel syndrome
  • Chronic use of prescription anti-inflammatory medications
  • Smoking
  • Alcohol intake >7 alcoholic drinks per week
  • Unwillingness to maintain body weight during participation in the study
  • triglyceride (TG) > 400 mg/dL
  • Unwillingness to adhere to diet and study protocol
  • Weight gain or loss of more than 15 lb within 6 months prior to enrollment
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00175084

Locations
United States, Massachusetts
Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University
Boston, Massachusetts, United States, 02111
Sponsors and Collaborators
Tufts University
Investigators
Principal Investigator: Alice H Lichtenstein, D.Sc. Tufts Medical Center
  More Information

Additional Information:
No publications provided

Responsible Party: Tufts University
ClinicalTrials.gov Identifier: NCT00175084     History of Changes
Other Study ID Numbers: HL58008-1188
Study First Received: September 8, 2005
Last Updated: May 21, 2014
Health Authority: United States: Institutional Review Board

Additional relevant MeSH terms:
Cardiovascular Diseases
Hyperlipidemias
Metabolic Syndrome X
Dyslipidemias
Lipid Metabolism Disorders
Metabolic Diseases
Insulin Resistance
Hyperinsulinism
Glucose Metabolism Disorders

ClinicalTrials.gov processed this record on August 26, 2014