WAHA: Walnuts and Healthy Aging
Study Details
Study Description
Brief Summary
This will be a systematic investigation of the role of walnuts in preventing or slowing age related cognitive decline and age related macular degeneration. 700 subjects will be recruited between 2 sites, Loma Linda University in California, USA and Hospital Clinic in Barcelona, Spain. Participants will be randomly assigned to either the walnut group or the control group for a 2 year intervention. Baseline and annual data will be collected and analyzed.
Condition or Disease | Intervention/Treatment | Phase |
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N/A |
Detailed Description
Epidemiological studies suggest that nutrients such as n-3 polyunsaturated fatty acid, antioxidants and B-vitamins may protect against age related cognitive decline. Small human studies have shown beneficial effects of polyphenol rich foods on cognition and age related macular degeneration. Walnuts are a rich source of n-3 polyunsaturated fatty acid, alpha-linolenic acid, antioxidants, polyphenols and other bioactive compounds. A 2-year intervention will be conducted with healthy, elderly subjects to investigate the role of walnuts in preventing or slowing age related cognitive decline and age related macular degeneration.
350 subjects, age 63 to 79 years, will be recruited at each of 2 sites, Loma Linda University in California and Hospital Clinic in Barcelona. Participants will be randomly assigned to one of two groups: walnut group (habitual diet with 1 or 2 oz/d walnut supplement) or control group (habitual diet only). At baseline and yearly, cardiometabolic risk factors, red blood cell membrane fatty acids, urinary polyphenols and biomarkers of inflammation and oxidation will be measured. Eye exam, blood pressure and cognitive function tests will be measured at the beginning and end of 2 years. At the Barcelona site only, participants will be given a brain MRI and carotid ultrasound.
Descriptive results will be reported as mean plus/minus standard deviation. Primary analysis will be carried out on the basis of groups as randomly assigned. Results will be presented as appropriate effect sizes with a measure of precision (95% CI). Analysis of covariates gender, age, educational status will be conducted.
Study Design
Arms and Interventions
Arm | Intervention/Treatment |
---|---|
Active Comparator: Walnut group This group will have their habitual diet supplemented with 30 to 45g (1 to 1.5 oz) of walnuts daily. |
Dietary Supplement: Walnuts
30 to 60g (1 to 2 oz) per day of walnuts
|
Active Comparator: Control group This group will eat their habitual diet and refrain from eating walnuts. |
Other: habitual diet
Dietary information will be provided
|
Outcome Measures
Primary Outcome Measures
- Changes from baseline in global cognitive composite score [2 years]
The composite score will be calculated using the scores from the tests listed below. We will calculate the standardized scores of each test as the score of each participant minus the group mean and divide by its standard deviation. The composite score is the mean of the standardized scores. The 12 tests are: Rey Auditory Verbal Learning Test (RAVLT), Rey-Osterrieth Complex Figure (ROCF), Semantic Fluency (Animals), Boston Naming Test (BNT), Visual Object and Space Perception Battery (VOSP), Block Design section from the Wechsler Adult Intelligence Scale (WAIS-III), Trail Making Test (TMT), FAS Word Fluency, Stroop Color Word Test, Symbol Digit Modalities Test (SMDT) Digit Span from the WAIS-III and Conners Continuous Performance Test (CPT-II).
- Changes from baseline in macular degeneration [2 years]
This will be assessed: by stereoscopic digitized color fundus images graded by International Classification System for Age-Related Maculopathy (score range. 0 to 4; the higher the score, the worse the condition); by optical coherence tomography (OCT) measurements of macular thickness (in µm); by optical coherence tomography (OCT) measurements of retinal nervous fiber layer thickness (in µm).
Secondary Outcome Measures
- Change from baseline in brain cortical thickness [2 years]
Changes will be assessed by brain magnetic resonance imaging (MRI) on a randomly selected subset of participants. Only in Barcelona center. Unit of measure is mm2.
- Change from baseline in voxel-based morphometry [2 years]
Changes will be assessed by brain magnetic resonance imaging (MRI) using GM density maps on a randomly selected subset of participants. Only in Barcelona center. Unit of measure is GM density.
- Change from baseline in white matter hyperintensity volumes [2 years]
Changes will be assessed by brain magnetic resonance imaging (MRI) on a randomly selected subset of participants. Only in Barcelona center. Unit of measure is mL.
- Change from baseline in perfusion arterial spin labeling [2 years]
Changes will be assessed by brain magnetic resonance imaging (MRI) on a randomly selected subset of participants. Only in Barcelona center. Unit of measure is ml/100 g/min.
- Changes from baseline in brain activation [2 years]
Changes will be assessed by Functional MRI (fMRI) on a randomly selected subset of participants. Only in Barcelona center. There are no units of measure.
Other Outcome Measures
- Change in carotid Intima-media thickness (mm) [2 years]
Changes will be assessed by high-resolution ultrasound. Only in Barcelona center.
- Incidence of plaque presence in carotid artery (yes/no) [2 years]
Changes will be assessed by high-resolution ultrasound. Only in Barcelona center.
- Change in carotid atheroma plaque height (mm) [2 years]
Changes will be assessed by high-resolution ultrasound. Only in Barcelona center.
- Change in body mass index (kg/m2) [2 years]
BMI will be calculated as weight in kilograms divided by height in metres squared
- Change in waist circumference (cm) [2 years]
Waist circumference will be measured to the nearest 0.5 cm by using an anthropometric tape midway between the lowest rib and at the iliac crest at minimal respiration
- Change in total fat (g) [2 years]
Changes will be assessed by Dual-energy X-ray absorptiometry. Only in Barcelona center.
- Change in Total lean tissue (g) [2 years]
Changes will be assessed by Dual-energy X-ray absorptiometry. Only in Barcelona center.
- Change in fasting serum total cholesterol (mg/dL) [2 years]
Fasting serum total cholesterol will be measured by a standard enzymatic method
- Change in fasting serum LDL-cholesterol (mg/dL) [2 years]
Fasting serum LDL-cholesterol will be estimated by the Friedewald formula
- Change in fasting serum HDL-cholesterol (mg/dL) [2 years]
Fasting serum HDL-cholesterol will be measured by a precipitation technique
- Change in fasting serum triglycerides (mg/dL) [2 years]
Fasting triglycerides will be measured by a standard enzymatic method
- Change in serum brain-derived neurotrophic factor (pg/mL) [2 years]
Assessed by ELISA
- Change in serum soluble-Selectin (ng/mL) [2 years]
Assessed by ELISA
- Change in serum soluble-intercellular Adhesion Molecule 1 (ng/mL) [2 years]
Assessed by ELISA
- Change in serum soluble-vascular cell adhesion molecule 1 (ng/mL) [2 years]
Assessed by ELISA
- Change in serum amyloid A (ng/mL) [2 years]
Assessed by ELISA
- Change in serum granulocyte-macrophage colony-stimulating factor (pg/mL) [2 years]
Assessed by ELISA
- Change in serum interferon-gamma (pg/mL) [2 years]
Assessed by ELISA
- Change in serum interleukin-1beta (pg/mL) [2 years]
Assessed by ELISA
- Change in serum interleukin-6 (pg/mL) [2 years]
Assessed by ELISA
- Change in serum tumor necrosis factor alpha (pg/mL) [2 years]
Assessed by ELISA
Eligibility Criteria
Criteria
Inclusion Criteria:
-
63 to 79 years old
-
healthy men and women
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able to attend clinic at a study sites
Exclusion Criteria:
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illiteracy or inability to understand the protocol
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unable to undergo neurophysiological tests
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morbid obesity (BMI greater than or equal to ≥ 40 kg/m2)
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uncontrolled diabetes (HbA1c>85)
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uncontrolled hypertension
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prior cerebrovascular accident
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any relevant psychiatric illness, including major depression
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advanced cognitive deterioration, dementia
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other neurodegenerative diseases (i.e. Parkinson's disease)
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any chronic illness expected to shorten survival (heart, liver, cancer, etc)
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bereavement in the first year of loss
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bad dentures unless fixable dental prostheses are used
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allergy to walnuts
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customary us of fish oil or flaxseed oil supplements
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eye related exclusion criteria
Contacts and Locations
Locations
Site | City | State | Country | Postal Code | |
---|---|---|---|---|---|
1 | Loma Linda University, Department of Nutrition | Loma Linda | California | United States | 92350 |
2 | Hospital Clinic, University of Barcelona | Barcelona | Spain | 08036 |
Sponsors and Collaborators
- Loma Linda University
- University of Barcelona
- California Walnut Commission
Investigators
- Principal Investigator: Joan Sabate, MD, DrPH, Chair, Department of Nutrition
- Principal Investigator: Emilio Ros, MD, PhD, Director Lipid Clinic, Endocrinology & Nutrition Service
Study Documents (Full-Text)
None provided.More Information
Publications
None provided.- 5120066
- 670715-3833