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De la lutéine pour protéger le cerveau en plus des yeux?

25/07/2014 | Etudes Compléments alimentaires et Etudes Anti-âge

 

Macular Pigment, Visual Function, and Macular Disease among Subjects with Alzheimer’s Disease: An Exploratory Study
Journal Journal of Alzheimer’s Disease             July 02, 2014       John M. Nolan

Background: The macula (central retina) contains a yellow pigment, comprising the dietary carotenoids lutein (L), zeaxanthin (Z), and meso-zeaxanthin, known as macular pigment (MP). The concentrations of MP’s constituent carotenoids in retina and brain tissue correlate, and there is a biologically-plausible rationale, supported by emerging evidence, that MP’s constituent carotenoids are also important for cognitive function. Objective: To investigate if patients with Alzheimer’s disease (AD) are comparable to controls in terms of MP and visual function. Methods: 36 patients with moderate AD and 33 controls with the same age range participated. MP was measured using dual-wavelength autofluorescence (Heidelberg Spectralis®); cognitive function was assessed using a battery of cognition tests (including Cambridge Neuropsychological Test Automated Battery). Visual function was recorded by measuring best corrected visual acuity (BCVA) and contrast sensitivity (CS). Serum L and Z concentrations (by HPLC) and age-related macular degeneration (AMD, by retinal examination) status were also assessed. Results: In the AD group, central MP (i.e., at 0.23°) and MP volume were significantly lower than the control group (p < 0.001 for both), as were measures of BCVA, CS, and serum L and Z concentrations (p < 0.05, for all). Conclusion: AD patients were observed to exhibit significantly less MP, lower serum concentrations of L and Z, poorer vision, and a higher occurrence of AMD when compared to control subjects. A clinical trial in AD patients designed to investigate the impact of macular carotenoid supplementation with respect to MP, visual function, and cognitive function is merited.

Relationships between macular pigment optical density and cognitive function in unimpaired and mildly cognitively impaired older adults
Neurobiology of AgingVolume 35, Issue 7, Pages 1695–1699, July 2014   Lisa M. Renzi

Low carotenoid status (especially of the xanthophylls, lutein [L], and zeaxanthin [Z]) is common in older adults and has been associated with a number of degenerative diseases of the central nervous system ranging from retina (e.g., macular degeneration) to brain (e.g., Alzheimer’s disease). In this study, we tested whether retinal measures of L + Z (macular pigment optical density [MPOD]), used as a surrogate for brain L + Z levels, were related to cognitive function when comparing healthy older adults with mildly cognitively impaired older adults. Twenty-four subjects with mild cognitive impairment were compared with 24 matched controls. Subjects were matched with respect to age, body mass index, ethnicity, sex, and smoking status. Degree of cognitive impairment and cognitive ability was determined via structured clinical interview. MPOD was measured psychophysically. In healthy older adults, MPOD was only related to visual-spatial and constructional abilities (p = 0.04). For subjects with mild cognitive impairment (MCI), however, MPOD was broadly related to cognition including the composite score on the mini-mental state examination (p = 0.02), visual-spatial and constructional abilities (p = 0.04), language ability (p = 0.05), attention (p = 0.03), and the total scale on the Repeatable Battery for the Assessment of Neuropsychological Status (p = 0.03). It is possible that L/Z status may be more strongly related to cognition when individuals are considered with established onset of cognitive decline.


Lutein is the Predominant Carotenoid in Infant Brain: Preterm Infants Have Decreased Concentrations of Brain Carotenoids.

J Pediatr Gastroenterol Nutr. 2014 Mar 31. [Epub ahead of print] Vishwanathan R

Lutein and zeaxanthin are dietary carotenoids that may influence visual and cognitive development. The objective of this study was to provide the first data on distribution of carotenoids in the infant brain and compare concentrations in preterm and term infants.

METHODS::

Voluntarily donated brain tissues from 30 infants who died during the first 1.5 years of life were obtained from the NICHD Brain and Tissue Bank. Tissues (hippocampus and prefrontal, frontal, auditory and occipital cortices) were extracted using standard lipid extraction procedures and analyzed using reverse phase HPLC.

RESULTS::

Lutein, zeaxanthin, cryptoxanthin and β-carotene were the major carotenoids found in the infant brain tissues. Lutein was the predominant carotenoid accounting for 59% of total carotenoids. Preterm infants (n = 8) had significantly lower concentrations of lutein, zeaxanthin and cryptoxanthin in their brain compared to term infants (n = 22) despite similarity in postmenstrual age. Among formula-fed infants, preterm infants (n = 3) had lower concentrations of lutein and zeaxanthin compared to term infants (n = 5). Brain lutein concentrations were not different between breast milk-fed (n = 3) and formula-fed (n = 5) term decedents. In contrast, term decedents with measurable brain cryptoxanthin, a carotenoid that is inherently low in formula, had higher brain lutein suggesting that type of feeding is an important determinant of brain lutein concentrations.

CONCLUSIONS::

These data reveal preferential accumulation and maintenance of lutein in the infant brain despite under representation in the typical infant diet. Further investigation on the impact of lutein on neural development in preterm infants is warranted.

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