Bioaccessibility of Vitamin D from Bread Fortified with UV‐Treated Yeast is Lower than Bread Fortified with Crystalline Vitamin D2 and Bovine Milk

Abstract

UV‐treated yeast may be used as a vitamin D fortificant in bakery products, yet the vitamin D status of rats fed bread fortified with vitamin D2 enhanced yeast was lower than those fed a diet with crystalline vitamin D3. The purpose of this study was to determine whether the digestive release and micellarization (bioaccessibility) of vitamin D from yeast might be a limiting factor. White wheat and whole wheat bread fortified with vitamin D2‐enhanced yeast or crystalline vitamin D2 and vitamin D3 fortified bovine milks (skim, 2%, and whole) were subject to in vitro digestion, and analyzed by HPLC‐MS. Bioaccessibility was greater (p<0.05) from bovine milks (70–85%) than from breads fortified with vitamin D2 enhanced yeast (6.0–7.5%). Bioaccessibility was about 4× greater from breads fortified with crystalline vitamin D2 than those with vitamin D2 enriched yeast. Presence of intact yeast cells after simulated gastric and upper intestinal digestion suggests that vitamin D may be entrapped within yeast cell membranes. These data suggest that low digestive release of vitamin D from yeast may partly explain the low apparent bioavailability as compared to crystalline vitamin D2 and D3 and additional processing may be required to enhance the digestive release of vitamin D from yeast.Support or Funding InformationSupport provided by Purdue University and the USDA National Needs Fellowship Program.