A review of Vitamin D and its precursors in plants and their translation to active metabolites in meat

Vitamin D plays crucial roles in calcium absorption, bone metabolism, and immune, neurological and cardiovascular-related functions. In plants, it plays an important role in the form of D2 (ergocalciferol). Intake of vitamin D and its precursors by livestock varies with the specific forage crop, season, presence of fungal infestation and geographic location. Oral supplementation with vitamin D3 is highly effective at raising plasma and tissue levels of vitamin D and its metabolites in livestock. The vitamin D3 content varies in different cuts of meat, with higher levels typically correlated with increased fat content, although the same does not hold true for 25(OH)D3. The highest vitamin D3 content in meat is typically found in pork (mean content of 2.5 µg/kg) and chicken (mean of 2.4 µg/kg), followed by beef (mean of 2.2 µg/kg), with lamb containing the least (mean of 1.1 µg/kg). Storage and processing generally have minimal impact on the content of vitamin D or its metabolites in meat, aside from an increase on an as-is basis resulting from moisture loss. Due to their widespread availability and consumption, meat products appear to be a significant source of vitamin D and its hydroxylated forms for much of the global population.