The pre-clinical study, published in 'Annals of Microbiology', pinpoints the strain L. paracasei DG. as significantly increasing serum levels of 25(OH) D when supplemented simultaneously with vitamin D.
"We started from the assumption that Vitamin D is fat-soluble and given that lactic bacteria can have biosurfactant properties, ie contribute to the emulsion," explains Simone Guglielmetti, Professor of Microbiology at the Department of Food, Nutrition and Environmental Sciences at the University of Milan and co-author of the study. "We tested in vitro six bacterial strains belonging to the Lactobacillaceae family to see if they could improve the bioavailability of Vitamin D."
Six probiotic strains were screened for their ability to create a stable suspension of vit D3 in water: Lacticaseibacillus paracasei DG, L. paracasei LPC-S01, L. paracasei Shirota, L. rhamnosus GG, Limosilactobacillus reuteri DSM 17938, and Lactobacillus acidophilus LA5.
The Lacticaseibacillus paracasei DG strain displayed the strongest vitD3 solubilisation ability.
The authors then conducted an in vivo study to test this further. Different groups of mice were administered Vitamin D suspended in oil, either alone or mixed with L. paracasei DG, for a single dose or for a week.
"The specific properties of L. paracasei DG could be determined by the significant presence of an exopolysaccharide with a superior emulsifying capacity, which is produced solely by this probiotic," comments Guglielmetti.
The results suggest that the combined administration of L. paracasei DG with cholecalciferol may contribute to the maintenance of adequate serum levels of 25-hydroxyvitamin D in the population groups at risk of vitamin D deficiency.
"We are witnessing an epidemic deficiency Vitamin D especially in the Western world, an underdiagnosed deficiency that can be the basis for the development of a wide range of problems, the first of which is a greater susceptibility to infections, including viral ones.
"In addition, numerous subgroups are at greater risk of vitamin D deficiency and insufficiency, for example including pregnant women, people with increased skin melanin pigmentation, obese children and adults, and persons with abstinence from direct sun exposure.
"If the conclusions of the human study were equally positive, in the future for the first time we could recommend a specific bacterium, not just any probiotic, to be associated with Vitamin D.
"A probiotic such as L. paracasei DG, which in addition to increasing the bioavailability of Vitamin D also brings benefits to the intestine and therefore could reduce the possible adverse effects of Vitamin D, especially for those categories that need constant vitamin supplementation," concludes Guglielmetti.
"Co-administration of vitamin D3 and Lacticaseibacillus paracasei DG increase 25-hydroxyvitamin D serum levels in mice"
Source: Annals of Microbiology
Castagliuolo, I., Scarpa, M., Brun, P. et al.
"Co-administration of vitamin D3 and Lacticaseibacillus paracasei DG increase 25-hydroxyvitamin D serum levels in mice"
https://doi.org/10.1186/s13213-021-01655-3