Vitamin D deficiency is common in the US
By Dr. Emily Brown Reeves PhD, CNS
A 2015 study of 3.8 million individuals in the United States found that 33% were considered deficient in Vitamin D while another 60% had insufficient levels. Vitamin D deficiency is an epidemic in industrialized countries, like the US, because many activities occur indoors and the application of sunscreen is common practice for preventing skin cancer. At peak ultraviolet B (UVB) radiation, (290-315 nm) exposure of the entire body to full sun can result in the release of 20,000 IU of Vitamin D in approximately 10-15 minutes.
UVB radiation is absorbed by melanin, but it is also absorbed by sunscreen, glass, and clothing. Applying Sun Protection Factor (SPF) 30 reduces UVB absorption and Vitamin D production by 97.5%. Glass blocks nearly all UVB radiation so indoor sun exposure does not produce Vitamin D. At-risk populations for Vitamin D deficiency include those with osteoporosis, malabsorption syndromes, chronic kidney failure, liver disease, hyperparathyroidism, pregnant/lactating women, the elderly, the obese, and darker skinned individuals.
References
Kroll MH, Bi C, Garber CC, et al. Temporal relationship between vitamin D status
and parathyroid hormone in the United States. PLoS One. 2015;10(3):e0118108.
Holick MF. Photobiology of Vitamin D. Vitamin D. 2018:45-55. doi:10.1016/b978-0-12-809965-0.00004-5
Hollis BW. Circulating 25-hydroxyvitamin D levels indicative of vitamin D sufficiency:
implications for establishing a new effective dietary intake recommendation for vitamin D. J Nutr. 2005;135(2):317-322.
Holick MF, Binkley NC, Bischoff-Ferrari HA, et al. Evaluation, treatment, and prevention of
vitamin D deficiency: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011;96(7):1911-1930.
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