Oral vitamin D supplements raise blood levels better than enhanced sun exposure

Oral vitamin D supplementation raises its blood levels better than enhanced sun exposure.

Vitamin D and sunlight both are essential for life. Its deficiency can lead to back and bone problems and also increases susceptibility to infections. Despite this fact, Vitamin D deficiency prevails in about 80% of the Indian population. Now a new study has found that ≥ 20–30 minutes daily sun exposure with vitamin D supplementation significantly increases serum viatmin D concentration in the body.

The study, published in the journal Clinical Nutrition has found that enhanced sun exposure (daily ≥ 20–30 min around noon) and 500 IU/d of oral vitamin D₃ supplementation significantly increased serum 25OHD concentrations. Further, the enhanced sun exposure was not as effective as 500 IU/d of oral vitamin D₃supplementation.

Vitamin D inadequacy is associated with a wide range of diseases. However, optimal strategies to improve vitamin D status, especially in Asian populations, remain unclear. Hee-Kyung Joh, Department of Medicine, Seoul National University College of Medicine, Seoul, Korea, and colleagues tested the hypotheses:

1. relevant sun exposure or oral vitamin D supplementation would significantly increase serum 25-hydroxyvitamin D (25OHD) concentrations compared with placebo


2. sun exposure and supplementary vitamin D would be similar in serum 25OHD increases, and


3. the two interventions may have different effects on cardio-metabolic markers.

The researchers investigated the impact of sun exposure vs oral vitamin D supplementation on serum 25-hydroxyvitamin D levels in young adults in this 8-week randomized, placebo-controlled clinical trial. Specifically, they compared vitamin D-deficient adults in Seoul, Korea, with respect to changes in serum 25OHD concentrations. Participants were assigned to sun exposure (daily ≥ 20–30 minutes around noon; n=50), oral vitamin D₃ (500 IU/d; n=50), and control (placebo; n=50) groups.

Key findings of the study include:

• Both sun exposure and oral vitamin D₃ effectively increased serum 25OHD concentrations.


• Compared with placebo, the between-group least-squares mean (LSM) differences in changes were 2.2 ng/mLin the sun exposure group and 8.5 ng/mL in the oral vitamin D₃ group.


• Increases in serum 25OHD were greater with oral vitamin D₃ than with sun exposure.


• More participants in the oral vitamin D₃ group (54.2%) achieved serum 25OHD concentrations ≥20 ng/mL at week 8 than those in the sun exposure (12.2%) or control (4.3%) groups.


• Compliance with sun exposure advice was relatively low, and only those with adequate compliance had a significant increase in serum 25OHD.


• Changes in the cardio-metabolic markers were mostly insignificant in all groups.

"Enhanced sun exposure and 500 IU/d of oral vitamin D₃ supplementation significantly increased serum 25OHD concentrations. However, our protocol for sun exposure was not as effective as 500 IU/d of oral vitamin D₃supplementation," concluded the authors.

For detailed study log on to https://doi.org/10.1016/j.clnu.2019.03.021