The Influence of Daily Walnut Intake on Vascular Function and Associated Changes in Lipid Mediators and Primary Metabolites.
Overview
- Phase
- Not Applicable
- Intervention
- Not specified
- Conditions
- Overweight and Obesity
- Sponsor
- University of California, Davis
- Enrollment
- 20
- Locations
- 1
- Primary Endpoint
- Reactive Hyperemia Index (RHI)
- Status
- Completed
- Last Updated
- 2 years ago
Overview
Brief Summary
This study seeks to confirm and extend previous finding that four weeks of daily intake of 40 g of walnuts improve microvascular function, increasing the reactive hyperemia index (RHI), effects which were greatest in individuals with the worst initial RHI and correlating to circulating levels of vasoactive plasma epoxides. The current trial will enroll postmenopausal women who are at risk for cardiovascular disease due to their menopausal status and increased central adiposity. The initial trial focused on non-esterified (i.e. plasma) derived oxylipins, but substantial and unique changes were also observed in the esterified lipoprotein pool. The current study will add the esterified lipoprotein pool, important, as the mechanisms by which walnut intake influences endothelial function are currently undefined, but may include lipoprotein induced modulation of vascular hemostasis. As a secondary objective, primary metabolism and urolithin metabotype will be analyzed as a way to capture the influence of potential differences in habitual diet and metabolism on physiologic response. Therefore, this study will combine measures of cardiovascular physiology, metabolomics, and walnut-derived metabolite analyses to assess the 12 week influence of 40 g of daily walnut intake on the health of overweight and obese postmenopausal women.
Detailed Description
A dietary intervention trial will be conducted to achieve the following objectives and outcomes: Objective 1: Determine the 12 week change in bioactive lipid mediators, and their relationship to vascular function and platelet reactivity in overweight or obese postmenopausal women with walnut incorporation into their habitual diet. Objective 2: Assess the contribution of metabolic phenotype on the variance in biomarker response that includes both primary metabolism and urolithin metabotype. Expected Outcomes: Forty g of daily walnut intake for six- and 12- weeks is predicted to positively impact the production of bioactive lipid mediators known to favorably regulate cardiovascular and inflammatory signaling. AA derived oxylipins produced from COX, LOX, and CYP epoxygenases are known as regulators of inflammation, platelet activation and vascular function. Therefore, understanding how certain foods such as walnuts can change the relative ratio of PUFA substrates (i.e., AA, ALA, LA, EPA and DHA), and their subsequent bioactive species produced through these enzyme pathways is necessary for the refinement of dietary recommendations with regard to specific foods and dietary patterns aimed at reducing the risk of chronic disease. Although a positive outcome is predicted, there may be substantial variability in response. To explore potential genetic and dietary factors that may contribute to the variability in response to the above functional markers, primary metabolism and urolithin metabotype will be assessed. Objective 3: Assess the influence of 12 weeks of walnut intake on facial wrinkles in postmenopausal women. Expected Outcome: Tweleve weeks of 40 g of walnut intake will improve facial wrinkles and erythema in the study population, and the improvements will be related to changes in metabotype.
Investigators
Eligibility Criteria
Inclusion Criteria
- •Postmenopausal female: 45-65 years
- •Women: lack of menses for at least two years.
- •Subject is willing and able to comply with the study protocols.
- •Subject is willing to participate in all study procedures
- •BMI 25.0 - 35 kg/m2
Exclusion Criteria
- •BMI ≥ 35 kg/m2
- •Visit 1 Reactive Hyperemia Index (RHI; EndoPAT 2000) ≥ 2.4
- •Dislike or allergy for walnuts or walnut products
- •Self-reported use of daily anticoagulation agents including aspirin, NSAIDs
- •Vegan, Vegetarians, food faddists or those consuming a non-traditional diet
- •Fruit consumption ≥ 3 cups/day
- •Regular consumption of nuts (2-3 servings/week)
- •Vegetable consumption ≥ 4 cups/day for females
- •Coffee/tea ≥ 3 cups/day
- •Dark chocolate ≥ 3 oz/day
Outcomes
Primary Outcomes
Reactive Hyperemia Index (RHI)
Time Frame: 18 weeks
Digital microvascular function as measured by the EndoPAT2000
Framingham Reactive Hyperemia Index (fRHI)
Time Frame: 18 weeks
Digital microvascular function as measured by the EndoPAT2000
Secondary Outcomes
- Nitric Oxide metabolites (RNOX)(18 weeks)
- Collagen-Induced Platelet Aggregation(18 weeks)
- ADP-Induced Platelet Aggregation(18 weeks)
- Urolithin Metabolites(18 weeks)
- Plasma Fatty Acids(18 weeks)
- Esterified Fatty Acids(18 weeks)
- Total Nitrate and Nitrite(18 weeks)
- Plasma Oxylipins(18 weeks)
- Esterified Oxylipins(18 weeks)
- Ellagitannin Metabolites(18 weeks)