Vitamin D intakes are concerningly low (1). Relatively few foods contain high levels of vitamin D and therefore, coupled with varying diurnal ultraviolet-B (UVB) radiation intensity and poor supplement uptake, hypovitaminosis D is prevalent(Reference Cashman2). Food-based strategies, such as endogenous biofortification, are urgently warranted to increase vitamin D intakes and subsequently improve 25-hydroxyvitamin D (25(OH)D) concentrations. No research to date has explored the bioavailability of ultraviolet (UV)-biofortified pork in humans (Reference Neill, Gill and McDonald3). Therefore, the aim of the current study was to investigate the efficacy of vitamin D biofortified pork to increase 25(OH)D3 concentrations, compared to a dose-matched vitamin D3 supplement and control pork in adults. An acute randomised double-blind, controlled, three-way crossover study was conducted in healthy Caucasian adults (n = 14; age: 23 ± 6 y; body mass index: 21.8 ± 1.8 kg/m2). Participants received either biofortified pork derived from pigs exposed UVB light (5 μg vitamin D3/portion), control pork (1.8 μg vitamin D3/portion) or a supplement (5 μg vitamin D3), with a 2-week washout period between each visit. Blood samples were obtained at baseline and then 1.5, 3, 6, 9 and 24 hour postprandially. Serum 25(OH)D3 was analysed by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The study was registered at clinicaltrials.gov (NCT04207294). There was a significant effect of time (p < 0.01) and a significant treatment*time interaction (p < 0.05). UV pork and supplement significantly increased within-group serum 25(OH)D3 concentrations over timepoints (p < 0.05). Average peak blood concentration (Cmax) values were modestly higher with supplementation (Supplement: 44.3 nmol/L; UV pork: 42.4 mol/L; Control pork 38.4 nmol/L). Between-group analysis showed no significant difference at any timepoint and there were no significant differences in area under the curve (AUC) between treatments, even when split by vitamin D status (< or ≥ 50 nmol/L). The time to maximum concentration (Tmax) was 9 hours for UV pork and supplementation, and 3 hours for control pork. Vitamin D biofortified pork increased 25(OH)D3 concentrations and produced a similar response pattern as a dose-matched vitamin D supplement, but biofortification protocols should be further optimised to ensure differentiation from control (standard) pork. Future research should address chronic exposure to vitamin D-biofortified pork with greater vitamin D3 concentrations, thus identifying its contribution to longer-term vitamin D status.
Acknowledgments
The authors wish to thank Richard Little, David Lyttle and Sloane Browne from AFBI Hillsborough for their commitment to animal care and management. Gratitude is also expressed to Dr Sara Dobbin and Laura Beggan for their assistance with laboratory analysis, as well as Massimiliano Fontana and Maria Wesolowska for their help with the practical running of the human intervention. This work was funded as part of a Department for the Economy (DfE) Co-operative Awards in Science and Technology (CAST) PhD studentship, supported by Devenish Nutrition Limited.
