A longitudinal study of infants aged 12 to 18 months found that higher skin carotenoid concentrations at the start of the study predicted trends in improved cognitive development by 30 months. These infants also showed significant improvements in fine motor skills throughout the 12-month period, and improved ability to understand spoken language later in this period. The study was published in the Journal of Cognitive Enhancement.
Skin carotenoids are natural pigments that accumulate in human skin after being ingested in the diet. They are primarily obtained from fruits and vegetables rich in carotenoids, such as carrots, sweet potatoes, spinach, and tomatoes. Carotenoids include compounds such as beta-carotene, lycopene, and lutein, which are known for their antioxidant properties.
When these compounds are absorbed into the bloodstream, some of them are deposited on the skin, where they can be detected and measured. Skin carotenoid levels are considered a non-invasive biomarker of fruit and vegetable intake. Researchers sometimes use special optical equipment, such as reflectance spectroscopic scanners, to estimate carotenoid levels in the skin. Generally, higher skin carotenoid levels are associated with healthier dietary patterns and increased intake of plant-based foods.
Study author Laura M. Rosok and colleagues wanted to study changes in infants’ sensory memory, visual, cognitive, language, and motor skills from the second year of life to 12 months. They also wanted to find out whether skin carotenoid levels predicted developmental changes during this period. The study authors hypothesized that infants with higher concentrations of carotenoids in their skin would experience stronger developmental changes over the study period.
Study participants were young children recruited from east-central Illinois. They were 12 to 18 months old at the start of the study and 24 to 30 months old at the final assessment. Fifty-one infants began the study, 46 provided data at the midpoint of the study, and 41 of these participated in the final assessment.
Skin carotenoid concentrations in infants were measured using the Veggie Meter™, an instrument that identifies skin pigments within the carotenoid light spectrum based on reflectance spectroscopy. At the start of the study, 6 months after the start of the study, and 12 months after the start of the study, the parent or guardian of the participating infant provided three 24-hour recalls regarding the infant’s food intake. They reported what their infants ate and drank on three separate days over a two-week period.
Infants completed a battery of behavioral assessments using the Bayley Infant Development Scales IV Screening Test, which measures cognition, receptive and expressive communication, and fine and gross motor skills. They also completed two electroencephalographic (EEG) assessments: negative brain activity discrepancy and visual evoked potentials.
Mismatch negative measurements detect that the brain automatically detects deviations in a series of auditory stimuli. Visual evoked potentials are used to assess visual sensory pathways by recording brain wave activity while infants view specific images (inverted checkerboard patterns).
The results showed that infants with higher skin carotenoid levels at the start of the study experienced improvements in fine motor skills both in the first 6 months and throughout the 12-month study period. They also experienced an increase in their ability to understand spoken language (receptive communication) later in the study.
Interestingly, the researchers found no significant changes in the infants’ sensory memory or visual processing (EEG measurements) over 12 months, and these EEG results were not predicted by baseline skin carotenoid levels.
Although the data suggested there may be a link between carotenoid levels and improved overall cognitive function, this particular finding was not statistically significant, meaning the researchers could not conclusively prove the relationship.
“These findings suggest that skin carotenoids may be associated with cognitive, language, and motor development in young children,” the study authors concluded.
This study contributes to scientific knowledge regarding biochemical indicators of cognitive development. However, the design of this study does not allow us to infer causality from the results. Additionally, the authors noted that the sample was primarily white and from high-income households, which limits the generalizability of the findings to a broader, more diverse population.
The paper, “Associations between cutaneous carotenoids, sensory processing, and developmental milestones in Midwestern infants over 12 months” was authored by Laura M. Rosok, Lexi M. Fifield, Rhea Sarma, Shelby A. Keye, Anne M. Walk, Kara D. Federmeier, and Naiman A. Khan.
