Moderate Sun Exposure Is the Complementor in Insufficient Vitamin D Consumers

Shou-En Wu; Wei-Liang Chen

doi:10.3389/fnut.2022.832659

Moderate Sun Exposure Is the Complementor in Insufficient Vitamin D Consumers

Front Nutr. 2022 Mar 8:9:832659. doi: 10.3389/fnut.2022.832659. eCollection 2022.

Authors

Shou-En Wu^{1

2

3}, Wei-Liang Chen^{2

3

4}

Affiliations

¹ Department of Dermatology, Tri-Service General Hospital, School of Medicine, National Defense Medical Center, Taipei City, Taiwan.
² Division of Family Medicine, Department of Family and Community Medicine, Tri-Service General Hospital, School of Medicine, National Defense Medical Center, Taipei City, Taiwan.
³ Division of Geriatric Medicine, Department of Family and Community Medicine, Tri-Service General Hospital, School of Medicine, National Defense Medical Center, Taipei City, Taiwan.
⁴ Department of Biochemistry, National Defense Medical Center, Taipei City, Taiwan.

Abstract

Background and aims: Vitamin (Vit) D plays a vital role in human health, and the prevalence of Vit D deficiency worldwide has been a rising concern. This study investigates the serum 25-hydroxy-Vit D [25(OH)D] status in healthy US civilians and identifies how the two main sources, sun exposure and dietary Vit D intake, determine the final 25(OH)D levels in individuals.

Methods: A total of 2,360 of participants from The National Health and Nutrition Examination Survey (NHANES) 2009-2014 were analyzed. We divided the levels of sun exposure and dietary Vit D intake of all subjects into 10 strata and gave a score ranging from 1 to 10 points, respectively. Scores 1-5 in sun exposure and dietary intake were considered as relatively low exposure groups, whereas scores 6-10 were considered as relatively high exposure groups. Serum Vit D inadequacy was defined as <50 nmol/L. Linear and logistic regression analyses were used to examine the associations between sources of Vit D and serum 25(OH)D levels.

Results: In relatively low Vit D intake groups (Vit D intake score 1-5), relatively high sun exposure (sun exposure score >5) resulted in higher serum 25(OH)D levels (average 57 nmol/L) compared with relatively low sun exposure (sun exposure score <5) (average 50 nmol/L), whereas this difference became negligible in high intake groups (Vit D intake score 6-10). Moreover, the greatest slope occurred in the low Vit D intake curve (decile 3 of Vit D intake), which shows increased sun exposure time causing the greatest degree of change in serum 25(OH)D level in this group.

Conclusion: Sun exposure can significantly make up for deficiencies in subjects who consume insufficient dietary Vit D. Compared with the extra cost and time for building habits of Vit D supplementation, moderate sun exposure appears to be a simple and costless means for the public to start in daily practice.

Keywords: dietary intake; dietary supplements; sun exposure; vitamin D; vitamin D deficiency.