Bacteria from the gut influence the host micronutrient status

Micronutrient deficiencies or hidden hunger remains a serious public health problem in most low- and middle-income countries, with severe consequences for child development. Traditional methods of treatment and prevention, such as supplementation and fortification, have not always proven to be effective and may have undesirable side-effects (i.e., digestive troubles with iron supplementation). Commensal bacteria in the gut may increase bioavailability of specific micronutrients (i.e., minerals), notably by removing anti-nutritional compounds, such as phytates and polyphenols, or by the synthesis of vitamins. Together with the gastrointestinal mucosa, gut microbiota is also the first line of protection against pathogens. It contributes to the reinforcement of the integrity of the intestinal epithelium and to a better absorption of micronutrients. However, its role in micronutrient malnutrition is still poorly understood. Moreover, the bacterial metabolism is also dependent of micronutrients acquired from the gut environment and resident bacteria may compete or collaborate to maintain micronutrient homeostasis. Gut microbiota composition can therefore be modulated by micronutrient availability. This review brings together current knowledge on this two-way relationship between micronutrients and gut microbiota bacteria, with a focus on iron, zinc, vitamin A and folate (vitamin B9), as these deficiencies are public health concerns in a global context.

Automated summary

Micronutrient deficiencies or hidden hunger is a major public health problem, particularly in low- and middle-income countries, with significant impact on child development. Traditional methods of treatment and prevention have not always been effective and may have undesired side-effects. Gut microbiota, along with the gastrointestinal mucosa, plays a crucial role in enhancing the absorption of micronutrients and protecting against pathogens. However, the exact relationship between micronutrient malnutrition and gut microbiota is still poorly understood. This review provides current knowledge on the interaction between micronutrients and gut microbiota, specifically focusing on iron, zinc, vitamin A, and folate.