Data published in the Scientific Reports indicated that oral vitamin D3 supplementation at 50,000 IU per week led to decreases the relative abundance of bacteria in the phylum Firmicutes and increases in the relative abundance of bacteria in the Bacteroidetes phylum.
“A high ratio of Firmicutes to Bacteroidetes has been correlated with obesity and other diseases; while conversely a prebiotic intervention that decreased the Firmicutes to Bacteroidetes ratio resulted in improvements to gut permeability, metabolic endotoxemia and inflammation,” explained researchers from Sidra Medicine and Qatar University.
The study also found that the vitamin D supplements increased the abundance of the health-promoting taxa Akkermansia and Bifidobacterium.
Commenting independently on the study’s findings, Glenn Gibson, Professor of Food Microbiology and head of Food Microbial Sciences at the University of Reading in the UK, and a pioneer and world-renowned expert in prebiotics and probiotics, told NutraIngredients-USA: “This is a very well-done study showing interesting in vivo results. The positive effects of vitamin D on the micro biome are noteworthy.
“Moreover, the trial may have relevant for the current COVID pandemic given that both seem to have an involvement in helping entomology.”
The Qatar-based scientists recruited 80 female students at Qatar University to participate in their study. Despite being vitamin D deficient, the women were considered healthy. All the participants received the vitamin D3 supplements – there was no placebo group.
The results showed that vitamin D supplementation led to significant increases in gut microbial diversity, with the Bacteroidetes to Firmicutes ratio increasing, and the abundance of Akkermansia and Bifidobacterium also increasing.
The researchers also conducted additional analysis of “responders” vs “non-responders”, which they defined as the women who became vitamin D sufficient after supplementation, and those who did not. They found that the non-responders had lower levels of Bacteroides acidifaciens at the start of the study. They also found that this species declined further in the non-responders post-supplementation.
“Bacteroides acidifaciens has previously been proposed as a “lean bug” that could prevent obesity and improve insulin sensitivity,” they noted. “It is also one of the predominant commensal bacteria that promote IgA antibody production in the large intestine. Thus, we hypothesize that the vitamin D supplementation promotes the ‘farming’ of good bacteria in order to maintain immune–microbe homeostasis.”
To conclude, the researchers stated: “Our study also provides a proof-of-concept that the gut microbiota is informative in examining individualized responses to vitamin D supplementation, presenting a rationale for planning future clinical trials that focus on the inter and intra individual variation using multi-omics approaches such as genotyping, transcriptomics and proteomics.”
The sunshine vitamin
Vitamin D refers to two biologically inactive precursors - D3, also known as cholecalciferol, and D2, also known as ergocalciferol. Both D3 and D2 precursors are transformed in the liver and kidneys into 25- hydroxyvitamin D (25(OH)D), the non-active 'storage' form, and the active form 1,25-dihydroxyvitamin D (1,25(OH)2D).
To achieve a 25(OH)D blood levels of at least 30 ng/mL, the Endocrine Society Guidelines recommends infants, children and adults receive 400-1000 IUs, 600-1000 IUs and 1000-1500 IUs of vitamin D daily respectively. Requirements for obese adults are 2-3 times higher.
According to the recently published 2020-2025 Dietary Guidelines for Americans, “vitamin D recommendations are harder to achieve through natural sources from diet alone and would require consuming foods and beverages fortified with vitamin D. In many cases, taking a vitamin D supplement may be appropriate especially when sunlight exposure is limited due to climate or the use of sunscreen.”
Source: Scientific Reports
2020, Volume 10, Article number: 21641, doi: 10.1038/s41598-020-77806-4
“The potential role of vitamin D supplementation as a gut microbiota modifier in healthy individuals”
Authors: P. Singh, et al.