According to findings from Professor Christel Lamberg-Allardt from Helsinki University, bread baked with a baker’s yeast containing vitamin D2 maintained blood levels of the vitamin to approximately the same extent as a D2 supplement over a four-week period.
Vitamin D refers to two biologically inactive precursors - D3, also known as cholecalciferol, and D2, also known as ergocalciferol. The former is produced in the skin on exposure to UVB radiation (290 to 320 nm). The latter is derived from plants and only enters the body via the diet.
Both D3 and D2 precursors are hydroxylated in the liver and kidneys to form 25- hydroxyvitamin D (25(OH)D), the non-active 'storage' form, and 1,25-dihydroxyvitamin D (1,25(OH)2D), the biologically active form that is tightly controlled by the body.
While our bodies do manufacture vitamin D on exposure to sunshine, the levels in some northern countries are so weak during the winter months that our body makes no vitamin D at all, meaning that dietary supplements and fortified foods are seen by many as the best way to boost intakes of vitamin D.
One such option is bread, being a staple of many cultures. The new study involved 38 health women aged between 19 and 41 who had an average 25(OH)D level of 58.7 nmol/L at the start of the study. The women were randomly assigned to consume vitamin D2-fortified bread plus a placebo supplement, regular bread plus a vitamin D2 supplement, or regular bread and a placebo supplement. The daily dose of D2 from all sources was 25 micrograms, or 1,000 International Units (IU).
The data, which has not been seen in full by NutraIngredients, indicated that the decrease in 25(OH)D levels in the four weeks following consumption of the control bread and placebo supplement were not observed in either the vitamin D2-rich bread or the D2 supplement group.
“This four week trial clearly showed that bread baked with vitamin D2 containing yeast had an equal effect on serum 25(OH)D concentration as a vitamin D2 supplement,” said Prof Lamberg-Allardt.
The study was welcomed by Jean Chagnon, CEO of Lallemand, the company that provided the vitamin D2-rich bakers yeast. “Bread is a staple food consumed daily by persons of different ages and different ethnicities and yeast is a key ingredient in the production of bread. The simple process improvement used in making Lallemand VitaD Baker’s Yeast, with this scientific evidence will certainly result in a significant percentage of all breads and yeast leavened goods becoming new natural sources of vitamin D.
“This is good news at a time when the importance of this sunshine vitamin D is increasingly recognised by health professionals, public health officials and the general public,” added Chagnon.
A spokesperson for Lallemand told NutraIngredients that the new study builds on previous findings published in the Journal of Nutrition (2006, Vol. 136, pp. 123-127,) in that the earlier science used vitamin D3, “whereas the objective of this study was the bioavailability of vitamin D2”.
The data was presented as a poster and is available here. The spokesperson confirmed that the data will be submitted for publication in a peer-review journal.