Vitamin B-12 and the Gastrointestinal Microbiome: A Systematic Review

Area of Science:

• Microbiology
• Nutritional Science
• Public Health

Background:

• Vitamin B-12 deficiency is a significant public health issue with known health impacts.
• Emerging evidence suggests a role for vitamin B-12 in the gut microbiome's composition and function.
• Vitamin B-12 is crucial for bacterial enzymes in the gut microbiome, but its impact remains unclear.

Approach:

• A systematic review was conducted to examine the link between vitamin B-12 and the gut microbiome.
• Searched for in vitro, animal, and human studies assessing vitamin B-12 status, intake, or supplementation and gut microbiome composition.
• Included 22 studies (3 in vitro, 8 animal, 11 human observational).

Key Points:

• Nineteen studies reported associations between vitamin B-12 and gut microbiome outcomes like diversity and bacterial abundance.
• In vitro studies suggest vitamin B-12 may increase alpha-diversity and alter beta-diversity.
• Findings from animal and human studies were heterogeneous, with potential differences based on cobalamin form and co-interventions.

Conclusions:

• Vitamin B-12 intake, status, or supplementation is associated with gut microbiome characteristics.
• Further research, including prospective human studies and randomized trials, is needed to clarify vitamin B-12's impact on the human gut microbiome.
• Understanding this relationship is crucial for public health interventions and screening strategies.