Using HPLC to Uncover Links Between Vitamin D Levels and Body Composition in Women

Rula Amr, from the Department of Nutrition and Health Psychology at the American University of Madaba (Amman, Jordan), set out to investigate the understudied link between vitamin D status and body composition—particularly fat distribution and muscle mass—in adult women. Recognizing these factors as key indicators of overall health, Amr conducted a comprehensive study involving 397 Jordanian women aged 18–59. Vitamin D levels were measured using high performance liquid chromatography (HPLC). The findings were published in BMJ Nutrition, Prevention and Health (1).

Vitamin D deficiency (VDD) is particularly common among women; there is a particularly high occurrence of the deficiency among women who are obese (88%) compared with those with a normal weight (51%) (2). It is crucial to understand the nutritional status of vitamin D for a variety of factors, including the maintenance of bone, reproductive, immune and mental health, as well as its impact on body tissues, specifically adipose tissue and skeletal muscle, both of which possessing specific receptors for the vitamin (3,4).

There has been an increase on recent research focusing on the connection between vitamin D levels and body composition that stresses the important link between obesity and VDD (5). While most of the previous studies used standard metrics such as body mass index (BMI), waist circumference (WC) and body fat percentage (% BF) in evaluation of body composition, these metrics often ignore other crucial factors pertaining to fat distribution in the body (5,6). In addition, there is evidence that links vitamin D to skeletal muscle mass (SMM), and the contribution of VDD to reduced muscle mass reduction, a decrease in strength, and diminishing muscle function (7). Despite vitamin D’s critical role in the maintenance of muscle mass during pregnancy and postpartum (which affects functional capacity and quality of life), and the support it offers functional independence and reduction of the risk of complications related to muscle health throughout life, studies specifically examining these variables in women are rare, hence inspiring Amr’s research (8,9).

The data compiled from Amr’s study showed that age was the strongest predictor of vitamin D levels, with older women exhibiting higher mean concentrations (42.80±11.01 years in the adequate group vs 36.45±11.22 years in the inadequate group; p<0.001). Central adiposity measures were significantly associated with vitamin D adequacy: WC<88 cm (73.8% vs 5.0%, p<0.001) and waist-to-hip ratio (WHR) <0.85 (20.3% vs 9.1%, p=0.001). Generalized adiposity measures, including BMI, were not significant in univariate analysis (p=0.668), but BMI was a negative predictor in Lasso regression (β=-1.078, 95% CI -1.400 to -0.756). Skeletal muscle mass index (SMI BMI) showed a borderline negative association (p=0.054) (1).

According to Amr, age and central adiposity emerged as the strongest predictors of vitamin D levels, underscoring the importance of fat distribution over general measures of body fat. She argues that public health strategies should prioritize reducing central adiposity and promoting muscle health—particularly among younger women at risk of vitamin D deficiency (VDD). Although the study is cross-sectional, Amr maintains that the findings offer valuable insight into the key determinants of vitamin D status and emphasize the need for longitudinal research to establish causality and inform more effective intervention strategies (1).

References

1. Amr R. Interrelations of Vitamin D Status with Adiposity and Muscle Mass in Adult Women. BMJ Nutr. Prev. Health 2025, 8 (1), e000983. DOI: 10.1136/bmjnph-2024-000983
2. Karlsson, T.; Osmancevic, A.; Jansson, N. et al. Increased Vitamin D-Binding Protein and Decreased Free 25(OH)D in Obese Women of Reproductive Age. Eur. J. Nutr. 2014, 53, 259–267. DOI: 10.1007/s00394-013-0524-8
3. Halfon, M.; Phan, O.; Teta, D. et al. Vitamin D: A Review on Its Effects on Muscle Strength, the Risk of Fall, and Frailty. Biomed. Res. Int. 2015, 2015. DOI: 10.1155/2015/953241
4. Nimitphong, H.; Holick, M. F.; Fried, S. K. et al. 25-hydroxyvitamin D₃ and 1,25-dihydroxyvitamin D₃ Promote the Differentiation of Human Subcutaneous Preadipocytes. PLoS One 2012, 7. DOI: 10.1371/journal.pone.0052171•
5. Bennour, I.; Haroun, N.; Sicard, F. et al. Vitamin D and Obesity/Adiposity-A Brief Overview of Recent Studies. Nutrients 2022, 14. DOI: 10.3390/nu14102049
6. Ceglia, L.; da Silva Morais, M.; Park, L. K. et al. Multi-Step Immunofluorescent Analysis of Vitamin D Receptor Loci and Myosin Heavy Chain Isoforms in Human Skeletal Muscle. J. Mol. Histol. 2010, 41, 137–142. DOI: 10.1007/s10735-010-9270-x
7. Shoemaker, M. E.; Salmon, O. F.; Smith, C. M. et al. Influences of Vitamin D and Iron Status on Skeletal Muscle Health: A Narrative Review. Nutrients 2022, 14. DOI: 10.3390/nu14132717
8. Fernando, M.; Ellery, S. J.; Marquina, C. et al. Vitamin D-Binding Protein in Pregnancy and Reproductive Health. Nutrients 2020, 12. DOI: 10.3390/nu12051489
9. Pilz, S.; Zittermann, A.; Obeid, R. et al. The Role of Vitamin D in Fertility and during Pregnancy and Lactation: A Review of Clinical Data. Int. J. Environ. Res. Public Health 2018, 15. DOI: 10.3390/ijerph15102241