Vitamin B12 is naturally present in animal products, but it could be added to plant-based products through fermentation using the Propionibacterium freudenreichii bacterium. This study aims to investigate the absorption of vitamin B12 synthesized by Propionibacterium freudenreichii from products made with fermented faba bean. 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 vitamin B12 produced by P. freudenreichii bacteria, and the other bread (control bread) is fermented using L. brevis bacteria (does not produce vitamin B12). The participants will eat the study bread for two consecutive days during the study weeks, with a washout period of 12 days. Fasting blood samples are collected on day 1 before administration of the first dose of vitamin B12 and on day 3. Nutrient intake and food consumption will be analyzed from 3-day food records at the baseline and on the bread eating days. The study is carried out in a double-blinded crossover setting.

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.

Inclusion Criteria:

• Healthy
• Body mass index between 18.5 and 35 kg/m2
• No exclusion criteria listed below

Exclusion Criteria:

• Food allergies against ingredients in foods supplemented in the study
• pregnancy and/or breastfeeding
• Regular use of food supplements containg B12
• Blood donation within 3 months
• Alcohol consumption more than 24 measures per week
• Smoking, using snuff
• Iron, B12 or folate deficiency
• Anemia
• small intestinal bacterial overgrowth (SIBO)
• Gastritis
• Helicobacter pylori infection
• Acid reflux
• Chron's disease
• Celiac disease
• Pancreatitis
• Abdominal surgery
• Eating disorder
• Use of supplements containing vitamin B12 in the last year
• Vitamin B12 injection treatment in the last year
• Use of metformin, protein pump inhibitors or H2-receptor blockers

The data collected is confidential and cannot be shared.

The study is double-masked - neither the researchers or the participants know which bread they are eating.