Role of Xanthophylls in Visual Function
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: luteine and zeaxanthine, luteine, zeaxanthine, Placebo.
- Who it may be relevant to
- Registry conditions: Nutrition Deficiency (Xanth Deficiency) Due to A Particular Kind of Food. Basic parameters: from 16 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Center list to be confirmed — check the primary protocol.
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
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Overview
Ecy of lutein supplementation alone, or zeaxanthin supplementation alone, or a combination of both, compared to placebo, on the evolution of macular pigment density (MPOD) measured by fundus photography in XANTH-deficient patients receiving enteral nutrition.
Detailed description
Lutein and zeaxanthin are plant pigments belonging to the carotenoid family, and more precisely to the subfamily of xanthophylls (XANTH), which are oxygenated carotenoids. These phytochemicals are not synthesised by humans and are almost always present in our diet. They are significantly absorbed and transported in our body. They are present in various organs, e.g. the eye and the skin. They accumulate in very high concentrations in the central area of the human retina. Because of this high accumulation, it has been hypothesised that they play one or more specific roles in the eye. This has been confirmed by several studies which have shown that XANTHs are involved in protecting the eye from damage by certain light rays (blue) and age-related macular degeneration. Other studies suggest that XANTH may improve glare tolerance and contrast sensitivity. They may also improve sensitivity to red and green colour discrimination. However, identifying the exact relationship between XANTH and visual function in XANTH supplementation is complicated by two main problems. Firstly, XANTH supplementation does not always increase MPOD (Macular Pigment Optical Density), which is an indicator of the concentration of XANTH in the macula, because there are poor responders to XANTH, i.e. subjects who absorb it very poorly and/or transport it very poorly to the retina. Secondly, MPOD seems to reach a maximum value and a plateau, and increasing the dose of XANTH, or the duration of supplementation, does not increase MPOD further. This is particularly the case in individuals who already have a high MPOD, close to the maximum value, before supplementation because they often consume XANTH-rich foods, and/or because they are strong responders to XANTH. Therefore, although studies suggest a specific role for XANTH in visual function, the problem of initially high MPOD in some individuals, coupled with MPOD saturation, has not allowed previous studies to provide definitive evidence on their role(s) in visual function.
Interventions
- Dietary supplement luteine and zeaxanthine
luteine and zeaxanthine - Dietary supplement luteine
luteine - Dietary supplement zeaxanthine
zeaxanthine - Dietary supplement Placebo
Placebo
Primary outcome measures
- evolution of MPOD Baseline Vs M6 [Time frame: Baseline, month 6]
Secondary outcome measures (3)
- Linkage between MPDO and visual settings [Time frame: Baseline, Month 6]
- Linkage between MPOD and blood and xanth blodd count [Time frame: Baseline, Month 4 and Month 13(option)]
- Measurement of visual accuity and settings [Time frame: Baseline, Month 4, Month 7, Month 13(option)]
Eligibility criteria
Inclusion criteria
- On exclusive enteral nutrition for at least 6 months
- Exclusive enteral nutrition that is intended to be continued for at least 6 more months.
- No XANTH supplementation in the last 6 months.
- Able to sit up to allow visual examinations to be performed
- Sufficient understanding to perform visual examinations, at the discretion of the physician
- Written consent signed by the patient or agreement of their carer, trusted person, relative, family for patients with cognitive impairment (assessed using an MMS test). A patient with an MMSE test result ≤ 24 will be considered as having cognitive disorders.
Exclusion criteria
- Current treatment with hydroxychloroquine or any other drug known to cause ocular toxicity
- Visually impaired patient: patient unable to read text (font size 11) at close range, with visual correction if the patient usually wears it
- Unoperated cataracts in both eyes
- Pregnant or breastfeeding woman
- Patient under legal protection: guardianship or curatorship
- Participation in other research in the same field of dietary supplementation, which may interfere with the results of this research.
Secondary exclusion criteria :
- Absence of XANTH (lutein and zeaxanthin) deficiency\* in the blood sample taken at inclusion.
- Physical, ophthalmological or cognitive characteristics, evaluated at the Quinze-Vingt ophthalmological examination, which do not allow a reliable measurement of MPOD or of all the settings of visual function.
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: No
Study design
- Allocation
- Randomized
- Model
- Parallel assignment
- Masking
- Triple blind
- Primary purpose
- Treatment
Study locations
Center list to be confirmed — check the primary protocol.
Identifiers
NCT: NCT05794074 · APHP220293