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Trial record 36 of 99 for:    Oleic Acids

Effects of Walnuts on Central Blood Pressure, Arterial Stiffness Indices, Lipoproteins, and Other CVD Risk Factors

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ClinicalTrials.gov Identifier: NCT02210767
Recruitment Status : Completed
First Posted : August 7, 2014
Last Update Posted : October 19, 2018
Sponsor:
Collaborator:
California Walnut Commission
Information provided by (Responsible Party):
Penny Kris-Etherton, Penn State University

Brief Summary:
This study will evaluate the effects of walnut-derived ALA and bioactives on multiple CVD risk factors, including central blood pressure, arterial stiffness indices, inflammatory markers, urinary isoprostanes, vascular adhesion markers, and changes in lipids and lipoproteins. Gut microbiome changes due to walnut consumption will also be assessed using the 16S rRNA gene.

Condition or disease Intervention/treatment Phase
Cardiovascular Disease Other: Walnut Diet Other: Walnut Control Diet Other: Low ALA Diet Not Applicable

Detailed Description:

Diets containing nuts likely reduce cardiovascular disease (CVD) risk but the mechanisms remain poorly defined. Walnuts contain substantial amounts of polyunsaturated fatty acids (PUFAs), particularly alpha-linolenic acid (ALA), and are a rich source of bioactives. Many vegetable oils are high in PUFAs but most lack ALA and do not provide the same complement of bioactive compounds as walnuts. ALA is thought to improve cardiovascular health by modulating circulating lipid concentrations, altering membrane structure/function by enhancing the total ω-3 fatty acid content of cell membrane phospholipids, and reducing inflammatory reactions by inhibiting production of arachidonic acid-derived eicosanoids. Consumption of walnuts has consistently been shown to improve blood lipids/lipoproteins and vascular health. However, there remains much debate over what is the preferable replacement for saturated fat in the diet. Because of the ALA and bioactives that they provide, walnuts may confer specific CVD benefits. To study the effects of walnuts, in terms of both their ALA content and bioactive compounds, we will compare two test diets (one containing walnuts and one matched for PUFA and ALA content but devoid of walnuts and their bioactives) to a control diet matched for macronutrient and linoleic acid (LA) content but providing oleic acid in place of ALA. This diet design will provide information about how walnuts affect the selected endpoints of interest due to their bioactives as well as their ALA content, and whether walnut ALA is a superior substitute for dietary saturated fat compared to oleic acid.

Feeding protocol and study treatments:

This study is designed as a double-blind, 3-period, randomized, cross-over controlled feeding study. Prior to randomization, participants will complete a two week run-in on a standard Western diet. Each diet period treatment phase will be 6 weeks in duration, separated by 2-week washout periods. The three test diets are: 1) a walnut diet (WD; providing ~2.0 oz of walnuts per day); 2) a matched walnut control diet (WCD) that will provide the same fatty acid profile as the walnut diet, but will not contain walnuts (and their bioactives); and 3) a low ALA diet (LAD) with a similar macronutrient (and linoleic acid) composition as the WD and WCD, but using oleic acid to replace ALA. Study diets will be prepared in a metabolic kitchen, with three isocaloric meals and a snack provided each day, based on a 7-day rotating menu cycle. Participants will be instructed to consume only the prepared foods and limit their intake of alcohol to 2 drinks/week and caffeinated calorie-free beverages to 40 ounces (5 drinks) per day. Diets will be planned for every subject according to his/her energy requirements and will be nutritionally adequate. This diet design will permit the WD to be compared with the WCD and LAD and, thereby, allow us to ascertain the specific effects that walnuts and their bioactive components (including and beyond ALA) may have on CVD risk factors and artery health.


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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 46 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)
Primary Purpose: Other
Study Start Date : August 2014
Actual Primary Completion Date : April 2018
Actual Study Completion Date : April 2018

Arm Intervention/treatment
Experimental: Walnut Diet
Provides ~2 oz. walnuts/day (2-3% of total calories from alpha-linolenic acid [ALA])
Other: Walnut Diet
2 oz. walnuts/day (2-3% of total calories from ALA)

Active Comparator: Walnut Control Diet
Provides same fatty acid profile (<7% SFA, 9% MUFA, 14-15% PUFA, 2-3% ALA) as Walnut Diet, but is devoid of walnuts and their bioactives
Other: Walnut Control Diet
2-3% ALA but no walnuts provided

Placebo Comparator: Low ALA Diet
Provides similar macronutrient and linoleic acid profile but replaces ALA with oleic acid (<7% SFA, 12% MUFA, 12% PUFA, 0.5% ALA)
Other: Low ALA Diet
ALA replaced by oleic acid




Primary Outcome Measures :
  1. Change from baseline in central blood pressure at the end of diet period 1 (week 6), end of diet period 2 (week 14), and end of diet period 3 (week 22) [ Time Frame: End of diet period 1 (week 6), end of diet period 2 (week 14), end of diet period 3 (week 22) ]

Secondary Outcome Measures :
  1. Change in 24-hour ambulatory blood pressure [ Time Frame: Week 0, end of diet period 1 (week 6), end of diet period 2 (week 14), end of diet period 3 (week 22) ]
  2. Change in indices of arterial stiffness (pulse wave velocity) [ Time Frame: Week 0, end of diet period 1 (week 6), end of diet period 2 (week 14), end of diet period 3 (week 22) ]
  3. Change in lipoprotein particle size [ Time Frame: Week 0, end of diet period 1 (week 6), end of diet period 2 (week 14), end of diet period 3 (week 22) ]
    The VAP© Test provides a direct measure of the following lipid and lipoprotein classes and subclasses: LDL, Lp(a), IDL, LDL1, LDL2, LDL3, LDL4, HDL, HDL2, HDL3, VLDL, VLDL1+2, VLDL3, TC, TG, Non-HDL, Remnant Lipoproteins, ApoB100, and ApoA1

  4. Change in inflammatory cytokines (tumor necrosis factor-alpha and interleukin-6) [ Time Frame: Week 0, end of diet period 1 (week 6), end of diet period 2 (week 14), end of diet period 3 (week 22) ]
  5. Change in the composition of the gut microbiome [ Time Frame: Week 0, end of diet period 1 (week 6), end of diet period 2 (week 14), end of diet period 3 (week 22) ]
    This will be assessed via sequencing of microbial 16S rRNA from fecal samples.

  6. Change in serum C-reactive protein [ Time Frame: Week 0, end of diet period 1 (week 6), end of diet period 2 (week 14), end of diet period 3 (week 22) ]
  7. Change in serum glucose [ Time Frame: Week 0, end of diet period 1 (week 6), end of diet period 2 (week 14), end of diet period 3 (week 22) ]
  8. Change in serum insulin [ Time Frame: Week 0, end of diet period 1 (week 6), end of diet period 2 (week 14), end of diet period 3 (week 22) ]
  9. Change in urinary F2α-isoprostanes [ Time Frame: Week 0, end of diet period 1 (week 6), end of diet period 2 (week 14), end of diet period 3 (week 22) ]
  10. Change in lipid/lipoprotein profile [ Time Frame: Week 0, end of diet period 1 (week 6), end of diet period 2 (week 14), end of diet period 3 (week 22) ]
    Total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides

  11. Change in heart rate variability [ Time Frame: Week 0, end of diet period 1 (week 6), end of diet period 2 (week 14), end of diet period 3 (week 22) ]
  12. Change in vascular adhesion markers (VCAM and ICAM) [ Time Frame: Week 0, end of diet period 1 (week 6), end of diet period 2 (week 14), end of diet period 3 (week 22) ]


Information from the National Library of Medicine

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Ages Eligible for Study:   30 Years to 65 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Aged 30-65 years
  • BMI greater than 25 and less than or equal to 40 kg/m2
  • Non-smokers
  • TG < 350 mg/dL
  • LDL-C between the 25-95th percentile from NHANES:
  • Males: 105-194 mg/dL
  • Females: 98-190 mg/dL
  • Stage I hypertension:
  • SBP > 120 mmHg and/or DBP > 80 mmHg
  • SBP < 160 mmHg and DBP < 100 mmHg
  • Free of established CVD, stroke, diabetes, liver, kidney or autoimmune disease.

Exclusion Criteria:

  • Elevated BP (SBP ≥160 mmHg OR DBP ≥ 100 mmHg)
  • A history of myocardial infarction, stroke, diabetes mellitus, liver disease, inflammatory disease, kidney disease, and/or thyroid disease (unless controlled on medication).
  • Blood pressure or cholesterol-lowering medication use
  • Refusal to discontinue intake of putative cholesterol-lowering supplements (psyllium, fish oil capsules, soy lecithin, niacin, fiber, flax, and phytoestrogens).
  • Vegetarianism or other dietary practices that are inconsistent with the test diets
  • Nut allergies (Other food allergies will be reviewed on a case-by-case basis)
  • Refusal to discontinue nutritional supplements, herbs, vitamins or NSAID's
  • Latex allergy
  • Pregnant or lactating females

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02210767


Locations
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United States, Pennsylvania
Penn State University
University Park, Pennsylvania, United States, 16802
Sponsors and Collaborators
Penn State University
California Walnut Commission

Publications:

Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
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Responsible Party: Penny Kris-Etherton, Penn State University
ClinicalTrials.gov Identifier: NCT02210767     History of Changes
Other Study ID Numbers: PKE ALA
First Posted: August 7, 2014    Key Record Dates
Last Update Posted: October 19, 2018
Last Verified: October 2018

Additional relevant MeSH terms:
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Cardiovascular Diseases