Interlaboratory trial for measurement of vitamin D and 25(OH)D in foods and a dietary supplement using liquid chromatography-mass spectrometry

Authors: Roseland, Janet; PATTERSON, KRISTINE - Consultant; ANDREWS, KAREN - Consultant; PHILLIPS, KATHERINE - Virginia Polytechnic Institution & State University; PHILLIPS, MELISSA - National Institute Of Standards & Technology (NIST); Pehrsson, Pamela; DUFRESNE, GUY - Consultant; JAKOBSEN, JETTE - University Of Denmark; MAKOWSKI, ANDREW - Consultant; SCHEUERELL, CHAD - Covance Laboratories; LAROUCHE, GUILLAUME - Consultant; GUSEV, PAVEL - Consultant; SAVARALA, SUSHMA - Consultant; NGUYEN, QUYNHANH - Consultant; TAYLOR, CHRISTINE - National Institutes Of Health (NIH); WISE, STEPHEN - National Institute Of Standards & Technology (NIST); Harnly, James - Jim; Williams, Juhi; BETZ, JOSEPH - National Institutes Of Health (NIH)

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/14/2016
Publication Date: 4/5/2016
Citation: Roseland, J.M., Patterson, K., Andrews, K.W., Phillips, K.M., Phillips, M.M., Pehrsson, P.R., Dufresne, G.L., Jakobsen, J., Makowski, A.J., Scheuerell, C.R., Larouche, G.P., Gusev, P.A., Savarala, S., Nguyen, Q.V., Taylor, C.L., Wise, S.A., Harnly, J.M., Williams, J.R., Betz, J.M. 2016. Interlaboratory trial for measurement of vitamin D and 25(OH)D in foods and a dietary supplement using liquid chromatography-mass spectrometry. Journal of Agricultural and Food Chemistry. 64:3167-3175.

Interpretive Summary: Vitamin D is essential for bone development and maintenance in the body. Vitamin D deficiency is a worldwide concern with major health consequences. Sun exposure is a good way to get vitamin D, but if it is limited, food becomes an important source. Foods such as milk, some cereals and orange juice, to which vitamin D has been added, as well as supplements, provide much of a person’s daily needs. Other foods naturally contain vitamin D including meat, fish, poultry, and eggs, and these foods also have another form of vitamin D, called 25-hydroxyvitamin D [25(OH)D]. In order to estimate a person’s total vitamin D intake, both vitamin D and 25(OH)D needs to be included. However, only limited nutrient data exist for the 25(OH)D content of foods and dietary supplements. One reason for a lack of reliable food composition data, for both vitamin D and 25(OH)D, has been questions about accuracy and precision of the methods for chemically analyzing foods and supplements to generate such data. An important way to show that analytical methods are working correctly is to analyze a reference material which contains a known amount of what being measured. Few reference materials exist for vitamin D and no reference materials are available for 25(OH)D. The primary goal of this study was to evaluate whether vitamin D3 and 25(OH)D3 concentrations in food and dietary supplement materials could be measured with acceptable reproducibility. A secondary goal was to assess the possibility of using the materials as control or reference materials in future research. An interlaboratory study to measure vitamin D and 25(OH)D was conducted with five experienced laboratories, including three from the USA and two international. The laboratories used their own sample preparation methods and mass spectrometry for the final measurement. Five animal-based reference materials [including 3 commercially available Standard Reference Materials (SRMs) from the National Institute of Standards and Technology (NIST)] and one softgel dietary supplement were analyzed. Other than the vitamin D content of SRM 1577 Bovine Liver, having a very low vitamin D amount which was close to laboratory measurement limits, the results for the food materials from the five labs did not differ more than would be expected. For the supplement, its vitamin D and 25(OH)D results were acceptable among the labs. Thus it is possible to obtain consistent results among experienced laboratories for vitamin D3 and 25(OH)D3 in foods and a dietary supplement. NIST plans to use these study data for assigning vitamin D and 25(OH)D values to the three standard reference materials, for use in analysis of foods. Once the vitamin D and 25(OH)D values in the NIST materials are established, additional analytical work in this area can be conducted to accurately measure the amounts of these forms of vitamin D in foods and supplements. With this additional information on foods and supplements, the total vitamin D intake for people can be more accurately estimated.

Technical Abstract: Assessment of total vitamin D intake from foods and dietary supplements (DSs) may be incomplete if 25-hydroxyvitamin D [25(OH)D] intake is not included. However, 25(OH)D data for such intake assessments are lacking, no food or DS reference materials (RMs) are available, and comparison of laboratory performance has been needed. The primary goal of this study was to evaluate whether vitamin D3 and 25(OH)D3 concentrations in food and DS materials could be measured with acceptable reproducibility. Five experienced laboratories from the U.S. and other countries participated, all using liquid chromatograph tandem-mass spectrometry but no common analytical protocol. Five animal-based materials (including three commercially available RMs) and one DS were analyzed. Other than one material which had vitamin D3 content close to quantitation limits, reproducibility results for the materials were acceptable. Thus it is possible to obtain consistent results among experienced laboratories for vitamin D3 and 25(OH)D3 in foods and a DS.