Pork biofortification as a feasible food-based strategy to improve vitamin D intakes

Abstract

Vitamin D deficiency is a serious public health concern. Natural dietary sources and ultraviolet-B (UVB) cutaneous synthesis remains inadequate to maintain year-round 25-hydroxyvitamin D (25(OH)D) concentration (> 25 nmol/L).

A systematic review of the literature demonstrated the validity of vitamin D
biofortification via feed and/or UVB exposure, but highlighted clear knowledge gaps regarding the impact of biofortified foods, particularly meat, on consumer vitamin D status. Therefore, this thesis adopted a farm-to-fork approach, which aimed to investigate the efficacy of pork meat as a potential vehicle for vitamin D biofortification. Daily UVB exposure, coupled with 2000 IU/kg vitamin D in feed, resulted in higher vitamin D3, 25(OH)D3 and total vitamin D activity (vitamin D3 + [25(OH)D3 x 5]) in pork loin compared to that from control pigs (no UVB). Cooking increased the vitamin D concentration in pork loin, mince and sausage. Total vitamin D activity retention varied between pork products and cooking methods (90.5-130.3%) but did not significantly differ from 100%. A novel acute crossover postprandial study (n=14) showed a significant time*treatment effect of vitamin D3 biofortified pork (5 μg/portion), dose-matched vitamin D3 supplement and control pork; however, there was no significant difference between the three treatments regarding bioavailability to increase 25(OH)D3 concentrations. Evidently, UVB exposure should be further optimised in on-farm interventions to ensure provision of a greater single-dose of vitamin D3 to fully understand food matrix effects of biofortified meat. Using UK population data, dietary modelling demonstrated that increasing the vitamin D content by 50-200% in biofortified pork and pork products would theoretically increase consumer intakes by 5-20%, respectively.

In conclusion, the multidisciplinary research within this thesis provides clear rationale for vitamin D biofortification of pork meat as an important and novel food-based strategy to increase vitamin D supply within the food system and, ultimately, helping to reduce prevalence of hypovitaminosis D.

Date of Award	Mar 2022
Original language	English
Sponsors	Department for the Economy & Devenish Nutrition Limited
Supervisor	Kirsty Pourshahidi (Supervisor) & Chris Gill (Supervisor)