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Recommended summer sunlight exposure amounts fail to produce sufficient vitamin D status in UK adults of South Asian origin.
Am J Clin Nutr. 2011 Nov; 94(5):1219-24.AJ

Abstract

BACKGROUND

The cutaneous synthesis of vitamin D is dependent on UVB from sunlight, but melanin reduces the penetration of UVB and thus contributes to vitamin D insufficiency in individuals with darker skin. The national guidance provided on amounts of sunlight exposure in the United Kingdom is for the light-skinned population, and in the absence of dedicated information, darker-skinned people may attempt to follow this guidance.

OBJECTIVES

We determined the relative effect of a simulation of UK recommendations of summer sunlight exposure on the vitamin D status of individuals of South Asian ethnicity compared with that of whites.

DESIGN

In a prospective cohort study, simulated summer sunlight exposures were provided under rigorous dosimetric conditions to 15 adults (aged 20-60 y) of South Asian ethnicity, and serum 25-hydroxyvitamin D [25(OH)D] was measured weekly. Dietary vitamin D intake was estimated. Outcomes were compared with those of 109 whites (aged 20-60 y) treated with the identical UV-radiation exposure protocol.

RESULTS

At baseline (winter trough), all South Asians were vitamin D-insufficient [25(OH)D concentrations <20 ng/mL], and 27% of South Asians were vitamin D-deficient [25(OH)D concentrations <5 ng/mL]; although 25(OH)D concentrations increased postcourse (P < 0.0001), all South Asians remained vitamin D-insufficient. The mean increase in 25(OH)D was 4.3 compared with 10.5 ng/mL in the South Asian and white groups, respectively (P < 0.0001), and 90% of the white group reached vitamin D sufficiency postcourse. The median dietary vitamin D intake was very low in both groups.

CONCLUSIONS

Sunlight-exposure recommendations are inappropriate for individuals of South Asian ethnicity who live at the UK latitude. More guidance is required to meet the vitamin D requirements of this sector of the population. This study was registered at www.isrctn.org as ISRCTN 07565297.

Authors+Show Affiliations

Dermatological Sciences, Inflammation Sciences Research Group, School of Translational Medicine, University of Manchester, United Kingdom.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Clinical Trial
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

21918215

Citation

Farrar, Mark D., et al. "Recommended Summer Sunlight Exposure Amounts Fail to Produce Sufficient Vitamin D Status in UK Adults of South Asian Origin." The American Journal of Clinical Nutrition, vol. 94, no. 5, 2011, pp. 1219-24.
Farrar MD, Kift R, Felton SJ, et al. Recommended summer sunlight exposure amounts fail to produce sufficient vitamin D status in UK adults of South Asian origin. Am J Clin Nutr. 2011;94(5):1219-24.
Farrar, M. D., Kift, R., Felton, S. J., Berry, J. L., Durkin, M. T., Allan, D., Vail, A., Webb, A. R., & Rhodes, L. E. (2011). Recommended summer sunlight exposure amounts fail to produce sufficient vitamin D status in UK adults of South Asian origin. The American Journal of Clinical Nutrition, 94(5), 1219-24. https://doi.org/10.3945/ajcn.111.019976
Farrar MD, et al. Recommended Summer Sunlight Exposure Amounts Fail to Produce Sufficient Vitamin D Status in UK Adults of South Asian Origin. Am J Clin Nutr. 2011;94(5):1219-24. PubMed PMID: 21918215.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Recommended summer sunlight exposure amounts fail to produce sufficient vitamin D status in UK adults of South Asian origin. AU - Farrar,Mark D, AU - Kift,Richard, AU - Felton,Sarah J, AU - Berry,Jacqueline L, AU - Durkin,Marie T, AU - Allan,Donald, AU - Vail,Andy, AU - Webb,Ann R, AU - Rhodes,Lesley E, Y1 - 2011/09/14/ PY - 2011/9/16/entrez PY - 2011/9/16/pubmed PY - 2012/2/2/medline SP - 1219 EP - 24 JF - The American journal of clinical nutrition JO - Am J Clin Nutr VL - 94 IS - 5 N2 - BACKGROUND: The cutaneous synthesis of vitamin D is dependent on UVB from sunlight, but melanin reduces the penetration of UVB and thus contributes to vitamin D insufficiency in individuals with darker skin. The national guidance provided on amounts of sunlight exposure in the United Kingdom is for the light-skinned population, and in the absence of dedicated information, darker-skinned people may attempt to follow this guidance. OBJECTIVES: We determined the relative effect of a simulation of UK recommendations of summer sunlight exposure on the vitamin D status of individuals of South Asian ethnicity compared with that of whites. DESIGN: In a prospective cohort study, simulated summer sunlight exposures were provided under rigorous dosimetric conditions to 15 adults (aged 20-60 y) of South Asian ethnicity, and serum 25-hydroxyvitamin D [25(OH)D] was measured weekly. Dietary vitamin D intake was estimated. Outcomes were compared with those of 109 whites (aged 20-60 y) treated with the identical UV-radiation exposure protocol. RESULTS: At baseline (winter trough), all South Asians were vitamin D-insufficient [25(OH)D concentrations <20 ng/mL], and 27% of South Asians were vitamin D-deficient [25(OH)D concentrations <5 ng/mL]; although 25(OH)D concentrations increased postcourse (P < 0.0001), all South Asians remained vitamin D-insufficient. The mean increase in 25(OH)D was 4.3 compared with 10.5 ng/mL in the South Asian and white groups, respectively (P < 0.0001), and 90% of the white group reached vitamin D sufficiency postcourse. The median dietary vitamin D intake was very low in both groups. CONCLUSIONS: Sunlight-exposure recommendations are inappropriate for individuals of South Asian ethnicity who live at the UK latitude. More guidance is required to meet the vitamin D requirements of this sector of the population. This study was registered at www.isrctn.org as ISRCTN 07565297. SN - 1938-3207 UR - https://www.unboundmedicine.com/medline/citation/21918215/Recommended_summer_sunlight_exposure_amounts_fail_to_produce_sufficient_vitamin_D_status_in_UK_adults_of_South_Asian_origin_ L2 - https://academic.oup.com/ajcn/article-lookup/doi/10.3945/ajcn.111.019976 DB - PRIME DP - Unbound Medicine ER -