(P04-03-26) Skin Carotenoid Content Reflects Dietary Carotenoid Intake but Not APOE ε4 Status in an Alzheimer’s-Enriched Cohort

Objectives: Skin carotenoid content (SCC) measured by pressure-mediated spectroscopy (Veggie Meter®, VM) is a non-invasive biomarker of fruit and vegetable intake. In cohorts enriched for Alzheimer’s disease risk, genetic factors involved in lipid transport, such as apolipoprotein E (APOE) genotype, may influence carotenoid deposition independent of dietary intake. The objective of this study was to examine associations between dietary carotenoid intake and VM scores and to determine whether these associations persist after adjustment for APOE ε4 carrier status in an Alzheimer’s-enriched cohort.

Methods: Adults aged 50–90 years (n=75) from an Alzheimer’s disease–enriched cohort (Therapeutic Diets in Alzheimer’s Disease trial, TDAD; NCT03860792) completed dietary assessment using 3-day food records analyzed with the Nutrition Data System for Research (NDSR) and underwent VM measurement of SCC. Spearman correlations assessed associations between VM scores and dietary carotenoids and food group intake. Independent samples t-tests compared VM scores between APOE ε4 carriers and non-carriers. Multivariable linear models evaluated whether total dietary carotenoid intake was associated with VM scores after adjustment for age, sex, education, body mass index (BMI), total energy intake, and APOE ε4 carrier status.

Results: VM scores were positively correlated with dietary carotenoids, including vitamin A, β-carotene, α-carotene, β-cryptoxanthin, lutein + zeaxanthin, and lycopene (ρ=0.29–0.50, all p≤0.01). VM scores were also correlated with fruit, dark green vegetable, total vegetable, and total fruit + vegetable intake (ρ=0.30–0.43, all p≤0.01). VM scores did not differ between APOE ε4 carriers and non-carriers (p=0.82). Total dietary carotenoid intake was positively correlated with VM score (ρ=0.46, p< 0.001) and remained associated with VM score in multivariable models adjusting for age, sex, education, BMI, total energy intake, and APOE ε4 carrier status (p=0.03).

Conclusions: In an Alzheimer’s-enriched cohort, VM scores were associated with dietary carotenoid and fruit and vegetable intake and were not influenced by APOE ε4 carrier status, supporting its use as a dietary biomarker of fruit and vegetable intake independent of genotype.

Funding Sources: The TDAD trial was funded by the National Institute on Aging of the National Institutes of Health.