Iron deficiency is the most frequent nutritional deficiency in the world with an estimated 1.4 billion people affected. The usual way to fight iron deficiency is iron fortification, but this approach ...is not always effective and can have undesirable side effects including an increase in the growth and virulence of gut bacterial pathogens responsible for diarrhea and gut inflammation. Iron is mainly absorbed in the duodenum and is tightly regulated in mammals. Unabsorbed iron enters the colonic lumen where many microorganisms, referred to as gut microbiota, reside. Iron is essential for these bacteria, and its availability consequently affects this microbial ecosystem. The aim of this review is to provide further insights into the complex relationship between iron and gut microbiota. Given that overcoming anemia caused by iron deficiency is still a challenge today, gut microbiota could help identify more efficient ways to tackle this public health problem.
Abstract Faecal microbiota plays a critical role in human health, but its relationship with nutritional status among schoolchildren remains under-explored. Here, in a double-blinded ...cluster-randomized controlled trial on 380 Cambodian schoolchildren, we characterize the impact of six months consumption of two types of rice fortified with different levels of vitamins and minerals on pre-specified outcomes. We investigate the association between the faecal microbiota (16SrRNA sequencing) and age, sex, nutritional status (underweight, stunting), micronutrient status (iron, zinc and vitamin A deficiencies, anaemia, iron deficient anaemia, hemoglobinopathy), inflammation (systemic, gut), and parasitic infection. We show that the faecal microbiota is characterised by a surprisingly high proportion of Lactobacillaceae . We discover that deficiencies in specific micronutrients, such as iron and vitamin A, correlate with particular microbiota profiles, whereas zinc deficiency shows no such association. The nutritional intervention with the two rice treatments impacts both the composition and functions predicted from compositional analysis in different ways. (ClinicalTrials.gov (Identifier: NCT01706419))
The microbiota significantly impacts digestive epithelium functionality, especially in nutrient processing. Given the importance of iron for both the host and the microbiota, we hypothesized that ...host-microbiota interactions fluctuate with dietary iron levels. We compared germ-free (GF) and conventional mice (SPF) fed iron-containing (65 mg/Kg) or iron-depleted (<6 mg/Kg) diets. The efficacy of iron privation was validated by iron blood parameters. Ferritin and Dmt1, which represent cellular iron storage and transport respectively, were studied in tissues where they are abundant: the duodenum, liver and lung. When the mice were fed an iron-rich diet, the microbiota increased blood hemoglobin and hepcidin and the intestinal ferritin levels, suggesting that the microbiota helps iron storage. When iron was limiting, the microbiota inhibited the expression of the intestinal Dmt1 transporter, likely via the pathway triggered by Hif-2α. The microbiota assists the host in storing intestinal iron when it is abundant and competes with the host by inhibiting Dmt1 in conditions of iron scarcity. Comparison between duodenum, liver and lung indicates organ-specific responses to microbiota and iron availability. Iron depletion induced temporal changes in microbiota composition and activity, reduced α-diversity of microbiota, and led to Lactobacillaceae becoming particularly more abundant after 60 days of privation. By inoculating GF mice with a simplified bacterial mixture, we show that the iron-depleted host favors the gut fitness of Bifidobacterium longum.The microbiota significantly impacts digestive epithelium functionality, especially in nutrient processing. Given the importance of iron for both the host and the microbiota, we hypothesized that host-microbiota interactions fluctuate with dietary iron levels. We compared germ-free (GF) and conventional mice (SPF) fed iron-containing (65 mg/Kg) or iron-depleted (<6 mg/Kg) diets. The efficacy of iron privation was validated by iron blood parameters. Ferritin and Dmt1, which represent cellular iron storage and transport respectively, were studied in tissues where they are abundant: the duodenum, liver and lung. When the mice were fed an iron-rich diet, the microbiota increased blood hemoglobin and hepcidin and the intestinal ferritin levels, suggesting that the microbiota helps iron storage. When iron was limiting, the microbiota inhibited the expression of the intestinal Dmt1 transporter, likely via the pathway triggered by Hif-2α. The microbiota assists the host in storing intestinal iron when it is abundant and competes with the host by inhibiting Dmt1 in conditions of iron scarcity. Comparison between duodenum, liver and lung indicates organ-specific responses to microbiota and iron availability. Iron depletion induced temporal changes in microbiota composition and activity, reduced α-diversity of microbiota, and led to Lactobacillaceae becoming particularly more abundant after 60 days of privation. By inoculating GF mice with a simplified bacterial mixture, we show that the iron-depleted host favors the gut fitness of Bifidobacterium longum.
The consumption of rice bran has been shown to have a positive effect on nutritional status and prevention of chronic diseases related to hundreds of metabolites with bioactivity. Consumption after ...fermentation can lead to specific beneficial effects, yet is lacking complete characterization when fermented with diverse strains. The objective of this study was to examine the effect of fermentation on the rice bran metabolite profile. Bacterial probiotics (
and,
) were used to ferment rice bran alone or after incubation with yeast probiotic
. Fermented rice bran was methanol extracted and analyzed by UPLC-MS/MS. The metabolome of the two fermentation types was deeply modified when compared with non-fermented rice bran. The two-step fermentation provided alternative substrate to the bacteria in a few cases. Key metabolites of high nutritional value (essential amino acids, vitamins) and gut health (arabinose, maltotriose) were identified.
Vitamin A supplementation (VAS) has been implemented in over 82 countries globally, primarily because of its beneficial effect in preventing child mortality. Secular reductions in child mortality and ...the implementation of alternative programs to promote vitamin A intake have led to questions on the need for national VAS programs.
This study aimed to estimate child mortality changes related to VAS using current, scale-back, and scale-up coverage scenarios.
Data related to demographic characteristics, fertility, intervention coverage, anthropometry, child mortality and cause-of-death structure were integrated into the Lives Saved Tool (LiST). We estimated the cause-specific (LiST model) and all-cause mortality reductions related to VAS based on evidence from recent meta-analyses.
Between 2008 and 2018, VAS coverage declined in most sub-Saharan African (SSA) countries. In 2019 alone, 12% and 24% reductions in all-cause mortality related to VAS were expected to avert from 105,332 to 234,704 child deaths, respectively, in SSA; whereas the cause-specific mortality model (LiST) estimated that 141,670 child deaths were averted in 2019. Estimates of VAS-related child mortality reductions were highly variable among countries. Our scaling-back scenario led to highly variable country-level results, with expected increases in mortality rates, from a low of 0.04/1000 live births to as high as 49.3/1000 live births, suggesting that some countries could start considering scaling back, while others need to scale up.
Excess child mortality that would be preventable by VAS has declined, but is still significant in many SSA countries. While scale-up of VAS is needed for most of the countries, scaling back can also be considered in some countries. Policy decisions, however, should be guided by more recent data on food consumption, vitamin A statuses, child health, and vitamin A fortification coverage.
Folate (vitamin B9) and cobalamin (vitamin B12) deficiencies potentially affect millions of people worldwide, leading to different pathologies. In Ethiopia, the diet is characterized by high ...consumption of fermented cereal-based foods such as injera, a good source of folate but not of cobalamin, which is only found in foods of animal origin that are rarely consumed. Some of the bacteria responsible for the fermentation of cereals can synthesize cobalamin, but whether or not fermented cereal food products contain cobalamin remains underexplored. The objective of this study was to assess the folate and cobalamin content of injera collected from various households in Ethiopia at different stages of production. Global (16S rRNA gene sequencing) and specific (real-time PCR quantification of bacteria known for folate or cobalamin production) bacterial composition of these samples was assessed. UPLC-PDA was used to identify the cobalamin to see whether the active or inactive form was present. Surprisingly, teff flour contained 0.8 μg/100 g of cobalamin, most probably due to microbial contamination from the environment and the harvesting process. While fermentation increased the folate and cobalamin content in some households, their levels decreased in others. Conversely, cooking consistently reduced the level of the vitamins. Fresh injera contained, on average, 21.2 μg/100 g of folate and 2.1 μg/100 g of cobalamin, which is high, but with marked variation depending on the sample. However, the form of cobalamin was a corrinoid that is biologically inactive in humans. Injera fermentation was dominated by lactic acid bacteria, with significant correlations observed between certain bacterial species and folate and cobalamin levels. For example, a high proportion of Fructilactobacillus sanfranciscensis, a known folate consumer, was negatively correlated with the folate content of injera. On the contrary, Lactobacillus coryniformis, known for its cobalamin synthesis ability was present in high proportion in the cobalamin-rich samples. These findings highlight the complex interrelationship between microorganisms and suggest the involvement of specific bacteria in the production of folate and cobalamin during injera fermentation. Controlled fermentation using vitamin-producing bacteria is thus a promising tool to promote folate and cobalamin production in fermented food.
Rapid physical growth and the onset of menstruation during adolescence can increase the risk of iron deficiency (ID) and related adverse effects. However, little is known about the risk of anemia and ...ID among adolescent girls in Ethiopia. Therefore, we aimed to determine the prevalence of ID, low iron stores, and anemia and characterize selected risk factors in Huruta, Arsi Zone, Oromia Region, Ethiopia. A cross-sectional study was conducted among non-pregnant adolescent girls (15-19 years of age; n = 257). Data on household socio-demographic characteristics, anthropometric measurements, and women's dietary diversity score (WDDS) were collected. Hemoglobin (Hb) and serum ferritin (SF), C-reactive protein (CRP), and α-1-acid-glycoprotein (AGP) concentrations were measured. Diets were predominantly plant-based, with a low consumption of animal source foods, fruits, and dark-green leafy vegetables. Only 4% of the adolescent girls had adequate dietary diversity (WDDS ≥5), and 35% were underweight. The prevalence of anemia (Hb <11 g/dL, 8.7%) and clinical ID (SF <15 µg/L, 8.7%) was low, but 41% had marginal iron stores (SF <50 µg/L). The low prevalence of ID, despite a predominantly plant-based diet is atypical and calls for adapted strategies to address low iron stores in this and other similar settings of Ethiopia.
Scope
Fighting obesity and associated comorbidities through dieting is not always sustained and results in a subsequent weight gain, a phenomenon referred to as weight cycling. Diet is among the most ...important factors in modifying the composition of gut microbiota. The objective of this work is to determine whether weight cycling affects the composition and the predicted function of mouse fecal bacteria on a long‐term basis.
Methods and results
Mice fed for 40 weeks with either high fat (HF), low fat (LF), or cycled diets (starting and ending by one of the two diets, and the reverse) exhibit a bacterial profile specific to each of the four groups. A higher proportion of Firmicutes and Bacteroidota phyla are observed in mice on Hf and LF diet, respectively. The proportion of functions dedicated to amino acid metabolism is higher in mice on HF or LF/HF diets, whereas the mice on LF or HF/LF diets have a higher proportion of functions involve in carbohydrate metabolism and vitamin B biosynthesis.
Conclusion
Compared to continuous HF or LF diets, cyclic diet specifically alters the composition and function of the mouse fecal microbiota, suggesting that fight against weight gain should be considered on a long‐term basis.
Fighting obesity through dieting is not always sustained and results in a subsequent weight gain, a phenomenon referred to as weight cycling. We determined whether weight cycling affects mouse fecal bacteria on a long‐term basis. Compared to continuous High Fat (HF) or Low Fat (LF) diets, cyclic diet specifically alters the composition and function of the mouse fecal microbiota.
PDF
