Influence of a Probiotic Yoghurt on the Status of Vitamins B₁, B₂ and B₆ in the Healthy Adult Human

Abstract

Background/Aims: The main reason for this study was to determine whether yoghurt bacteria, being rich in some water-soluble vitamins, release them or utilize vitamins from their surroundings. Our study was trying to determine for the first time, if the viable bacteria of probiotic yoghurt are able to influence the parameters of the B-vitamin (B₁, B₂, B₆) status of the healthy adult human. Methods: The test yoghurt was commercially available probiotic yoghurt prepared with Streptococcus thermophilus and Lactobacillus acidophilus, enriched with Lactobacillus casei GG. Different chemical forms of all investigated B-vitamins were determined by HPLC methods. In order to determine the influence of the yoghurt flora, each of 12 subjects consumed four yoghurt portions 125 g each ( = 500 g) a day, containing thermally inactivated cultures during the first 2-week period and yoghurt without heat treatment during the second 2-week period. Results: The heat treatment of the probiotic yoghurt caused negligible changes in vitamin contents. The plasma levels of thiamin decreased significantly (p < 0.01) after the first 2-week period and kept on decreasing during the second 2-week period. A similar trend was found in the urinary excretion. The plasma levels of the B₂-vitamers were different. The flavin adenine dinucleotide concentrations increased significantly (p < 0.01) after the consumption of heat-treated yoghurt and decreased significantly (p < 0.05) after the following 2 weeks, in which the subjects received the untreated yoghurt. In contrast, the flavin mononucleotide plasma levels decreased during the first 2-week period and increased during the second part of the study, but the change was not statistically significant. The free riboflavin concentrations in plasma and urine showed a continuous but not significant increase. The concentrations of pyridoxal-5-phosphate in plasma increased after the consumption of yoghurt with the inactivated bacteria and decreased in the second part of the study. However, the differences were not significant. The excretion of thiamin, B₂- and B₆-vitamers in the faeces did not significantly change throughout the study period (p > 0.05). Conclusions: Our observations show that the bacterial flora of the examined yoghurt does not influence the vitamin B₁, B₂ and B₆ status of man. It seems likely that even lactobacilli of the ‘probiotic’ type which are vitamin B consumers can decrease the bioavailability of these vitamins for man. Obviously a thermal death of the cells did not induce a release of physiologically active vitamins.

B-Group vitamin production by lactic acid bacteria - current knowledge and potential applications

“…However, as riboflavin levels returned to normal when the intake of fermented milks was stopped (no long-term effect), the changes in plasma concentrations seem more likely the result of regular yoghurt consumption as a fermented dairy product, rather than of the specific intake of the probiotic bacteria (Fabian et al 2008). Previous results from this group showed that unlike some yoghurt starter cultures that are able to produce riboflavin, most probiotic strains of lactobacilli consume this vitamin and thus decrease their bioavailability in fermented products (Elmadfa et al 2001). Consequently, adequate selection of strains is essential to increase the concentration and bioavailability of this essential vitamin in fermented foods.…”

“…2008). Previous results from this group showed that unlike some yoghurt starter cultures that are able to produce riboflavin, most probiotic strains of lactobacilli consume this vitamin and thus decrease their bioavailability in fermented products (Elmadfa et al. 2001).…”

Riboflavin Production in Lactococcus lactis : Potential for In Situ Production of Vitamin-Enriched Foods

“…Furthermore, it has also been suggested that yogurt bacteria may utilize B vitamins from their surroundings, thus decreasing their bioavailability upon ingestion (13). The present study successfully applied two different approaches by which L. lactis NZ9000 as a model strain can be converted from a vitamin consumer into a vitamin "factory."…”

A general method for selection of riboflavin-overproducing food grade micro-organisms

“…The successful application of the roseoflavin resistance strategy in three diverse bacterial species shows that it is a readily employable system in an industrial setting to isolate starter strains that produce and secrete vitamin B2. This is particularly appealing when one considers that some yoghurt cultures have been shown to actually decrease the concentration of riboflavin in some products due to their consumption of the vitamin [ 41 ]. In a simultaneously performed collaborative study it was demonstrated that a fermented dairy product produced with P. freudenreichii B2336 was able to improve growth and riboflavin status of riboflavin-depleted animals [ 25 ].…”