Bioavailability of Vitamin B12 in Bread Using Fermented Faba Bean as B12 Source in Healthy Volunteers (BeanBread)

A human intervention study with healthy volunteers will be carried out to investigate the absorption of vitamin B12 synthesized by Propionibacterium freudenreichii from bread made with fermented faba bean. The study is conducted on healthy, 18-50-year-old volunteers. The study is carried out in a randomized, double-blinded, placebo-controlled crossover design.

The study products are wheat breads of which 30% of the dry weight has been replaced with fermented faba bean flour. One of the study breads contains fermented faba bean flour containing vitamin B12 produced by P. freudenreichii bacteria, and the other bread (control bread) contains faba bean flour fermented with L. brevis bacteria (does not produce vitamin B12). In addition to the study breads, the study participants are given a vitamin supplement containing cyanocobalamin as a positive control during one study week and a placebo supplement as a negative control for two weeks. During each study period, the subjects eat study breads and supplements for two consecutive days, three times a day. The study participants are otherwise allowed to follow their usual diet. On the morning of the first and third study day of each study period, a blood sample is taken from the subjects, from which the vitamin B12 bound to holotranscobalamin II and the total vitamin B12 concentration in the serum are determined. At the baseline of the study, the blood samples are also analyzed for folate, methylmalonate, homocysteine and creatinine concentrations.

Nutrient intake and food consumption will be analyzed from 3-day food records during the run-in week and each study week (total 9 days). The participants will report their gastrointestinal symptoms during the study periods.