Examining the Relationship Between Skin Carotenoids and Bone Health in Young Adults Following Various Specialized Diets

Strengthening bone mineral density between the ages of 18-24 is crucial for lifelong bone health, but common micronutrient deficiencies, especially in calcium and vitamin D, combined with low fruit and vegetable intake among young adults, can hinder this process, increasing the risk of osteopenia and osteoporosis later in life. Research has also shown that skin carotenoid scores (SCS) can influence bone mineral density (BMD), with higher scores often correlating to higher BMD measurements. This cross-sectional study explored the relationship between skin carotenoid measurements and bone mineral density among college students following a specialized diet. 1007 university students ages 18-24 were recruited between 2020-23 through an introductory nutrition class offered at a public land grant university in New Hampshire to participate in the College Health and Nutrition Assessment Survey (CHANAS). Participants were categorized as plant-based, gluten-free, low-carbohydrate, dairy-free, other specialized diet, or no specialized diet. SCS were measured in triplicate using the VeggieMeter®, a pressure-mediated reflection spectroscopy (RS) device that detects and quantifies skin carotenoids as a proxy for fruit and vegetable intake. Bone mineral density was recorded using bone ultrasound attenuation (BUA) z-scores measured by the bilateral calcaneus bone of the participant's left and right heels. Students were categorized as normal BMD, at risk (osteopenia), or osteoporosis risk using the guidelines of the z-score categorization created by the World Health Organization (WHO). Findings discovered that males exhibited a higher risk of osteoporosis than females (8.2% vs. 1.7%, p<0.05). Participants following specialized diets did not exhibit statistically significant differences in mean z-scores compared to those not following a specialized diet. A weak but significant positive correlation was found between SCS and BMD z-scores (r=0.07, p=0.03). Although a weak correlation was observed between skin carotenoid levels and bone health z-scores, findings suggest a potential link between short-term dietary quality and bone health. However, the impact of specialized diets on bone health was not significant after adjusting for confounding variables. Future longitudinal research is needed to clarify these relationships and explore the role of micronutrient intake in optimizing bone health during young adulthood.