Background. Avoiding of meat is the basic principle of vegetarian diet with several variants existing.In the present study we have focused on lacto-ovo-vegetarian (LOV) diet which includes dairy products and eggs. We have aimed to assess its long-term effect on vitamin B12 status and intended to verify the influence of natural and vitamin B12-fortified food.
Material and methods. The prospective study was carried out comprising 16 healthy omnivores (12 females, 4 males) who intentionally declared to follow strict LOV diet for at least 5 years. The studied group was divided into 2 subgroups. First subgroup followed LOV diet based entirely on natural products while the second consumed food fortified with B12 vitamin. Evaluation of vitamin B12 concentration was performed before and after 6, 12, 24 and 60 months from LOV diet implementation. Results. Five-years of LOV diet resulted in significant decrease of serum vitamin B12 concentrations in the whole studied group (p < 0.05). However, the significant drop of vitamin B 12 level was in fact limited to the subgroup consuming exclusively natural products (p < 0.05). In none of the subjects abnormal serum vitamin B12 levels were observed. Conclusions. Five-year lacto-ovo-vegetarian diet did not result in a risk of vitamin B12 deficiency in healthy subjects. However, the levels of serum vitamin B12 concentrations in a subgroup consuming natural diet tend to be significantly lower as compared with the group consuming fortified food. It confirms the need of follow-up (and potentially vitamin B12 fortification of food and/or its supplementation) in long-term lacto-ovo-vegetarians.