Pistachios and Neural Macular Pigment
|The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details.|
|ClinicalTrials.gov Identifier: NCT05283941|
Recruitment Status : Recruiting
First Posted : March 17, 2022
Last Update Posted : March 9, 2023
- Study Details
- Tabular View
- No Results Posted
- How to Read a Study Record
|Condition or disease||Intervention/treatment||Phase|
|Macular Degeneration Retinal Degeneration Retinal Diseases Eye Diseases||Dietary Supplement: Pistachio Group||Not Applicable|
Lutein and its isomer zeaxanthin (L/Z) are dietary carotenoids that cross the blood brain barrier and exclusively accumulate in the macular region of the retina, where they are referred to as macular pigment (MP). MP density (MPD) has been reported to be significantly related to decreased risk of age-related macular degeneration as well as cognitive function in both young and older adults. Studies in non-human primates and humans find that MPD is significantly related to lutein brain concentrations. MPD, a non-invasive measure, is thus a biomarker for brain concentrations of L/Z. This may be of interest given the report that L/Z concentrations in the older adult brain are positively related to a variety of pre mortem cognitive measures. Furthermore, L/Z supplementation was found to significantly improve verbal fluency scores in healthy older adults. Pistachios are a bioavailable source of L/Z. L/Z are transported in the circulation primarily on high density lipoproteins (HDL) and HDL levels were found to be significantly related to MPD. Thus, increasing dietary intake of L/Z as well as changing lipoprotein levels may impact MPD. This is of interest given that a pistachio enriched diet has been reported to improve lipid profile in healthy and mild hypercholesterolemic patients. Based on the sum of these findings, the objective of this study was to investigate the effect of a long-term pistachio intervention on MPD.
The overall goal of the proposal is to determine whether the consumption of pistachios is a practical way to increase L/Z status. This will primarily be accomplished by performing a nutritional study to demonstrate that pistachios are a bioavailable source of L/Z to neural tissue (i.e., MP). Cross-sectional and intervention studies report a significant relationship between L/Z levels and ocular and cognitive health. Current L/Z intakes in the U.S. are lower than levels associated with health. This randomized, parallel study will test the efficacy of pistachios on increasing L/Z neural status (i.e., MPD).
|Study Type :||Interventional (Clinical Trial)|
|Estimated Enrollment :||40 participants|
|Intervention Model:||Parallel Assignment|
|Masking:||Double (Investigator, Outcomes Assessor)|
|Official Title:||Pistachios and Neural Macular Pigment; a Randomized Controlled Trial|
|Actual Study Start Date :||June 10, 2022|
|Estimated Primary Completion Date :||November 30, 2023|
|Estimated Study Completion Date :||November 30, 2023|
Experimental: Pistachio Group
The pistachio group will receive pistachio nuts in 2-ounce packs. This group will consume one pack every day over the course of the 12-week study.
Dietary Supplement: Pistachio Group
Consumption of 2-ounce packs of pistachio nuts, daily, for 12 weeks.
No Intervention: Control (Usual Diet) Group
The control group will not receive pistachio nuts. They will be asked to make no changes and continue to eat their regular diet.
- Change from baseline Macular Pigment (MP) Density over 12 weeks [ Time Frame: Measured at baseline, 6 weeks and 12 weeks. ]A non-invasive psychophysical technique, known as heterochromatic flicker photometry (HFP), will be used to measure MP density of the retina.
- Serum concentrations of lutein and zeaxanthin (dietary carotenoids) [ Time Frame: Measured at baseline and 12 weeks. ]Serum carotenoids will be measured by HPLC.
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, Learn About Clinical Studies.
|Ages Eligible for Study:||40 Years to 70 Years (Adult, Older Adult)|
|Sexes Eligible for Study:||All|
|Accepts Healthy Volunteers:||Yes|
- Adult men and women, aged 40 - 70 years
- Body Mass Index (BMI): 20.0 - 36.9 kg/m2
- Low macular pigment density at baseline (<0.5 OD)
- Low lutein and zeaxanthin intake at baseline (<2 mg/d)
- Inability to perform the heteroflicker photometry procedures with or without corrective lenses (i.e. glasses or contact lenses) during in-house screening.
History of (self-reported):
- Fat malabsorption
- Use of drugs that interfere with fat absorption or metabolism
- Tree nut allergy
- Eye disease, including macular degeneration and cataracts
- Small bowel disease or resection
- Atrophic gastritis
- Insulin-requiring diabetes
- > 14 alcoholic drinks per week
- Pancreatic disease
- Bleeding disorders
- Pregnancy (or hoping to become pregnant during participation in the study)
- Carotenoid or fatty acid dietary supplements within 2 months of the study
- Non-English speaker
- Any condition that would make it unlikely that the participant would be able to complete the requirements of the study.
Individuals on lipid-lowering medication will be considered if they maintain their regimen throughout the study and meet all inclusion/exclusion criteria.
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): NCT05283941
|Contact: Tammy Scott, PhDfirstname.lastname@example.org|
|United States, Massachusetts|
|Clinical and Translational Research Center (CTRC) - Tufts||Recruiting|
|Boston, Massachusetts, United States, 02111|
|Contact: Olaniyi Ogunbodede 617-636-4714 email@example.com|
|Contact: Rupali Ranade (617) 636-4714 firstname.lastname@example.org|
|Principal Investigator:||Tammy Scott||Tufts University|
|Responsible Party:||Tufts University|
|Other Study ID Numbers:||
|First Posted:||March 17, 2022 Key Record Dates|
|Last Update Posted:||March 9, 2023|
|Last Verified:||March 2023|
|Individual Participant Data (IPD) Sharing Statement:|
|Plan to Share IPD:||No|
|Studies a U.S. FDA-regulated Drug Product:||No|
|Studies a U.S. FDA-regulated Device Product:||No|
age related macular degeneration
Eye Diseases, Hereditary