Towards a bidirectional decoloniality in academic global health: insights from settler colonialism and racial capitalism.

This Viewpoint considers the implications of incorporating two interdisciplinary and burgeoning fields of study, settler colonialism and racial capitalism, as prominent frameworks within academic global health. We describe these two modes of domination and their historical and ongoing roles in creating accumulated advantage for some groups and disadvantage for others, highlighting their relevance for decolonial health approaches. We argue that widespread epistemic and material injustice, long noted by marginalised communities, is more apparent and challengeable with the consistent application of these two frameworks. With examples from the USA, Brazil, and Zimbabwe, we describe the health effects of settler colonial erasure and racial capitalist exploitation, also revealing the rich legacies of resistance that highlight potential paths towards health equity. Because much of the global health knowledge production is constructed from unregenerate contexts of settler colonialism and racial capitalism and yet focused transnationally, we offer instead an approach of bidirectional decoloniality. Recognising the broader colonial world system at work, bidirectional decoloniality entails a truly global health community that confronts Global North settler colonialism and racial injustice as forcefully as the various colonialisms perpetrated in the Global South.

Effect of barley supplementation on the fecal microbiota, caecal biochemistry, and key biomarkers of obesity and inflammation in obese db/db mice.

PURPOSE: Barley is a low-glycemic index grain that can help diabetic and obese patients. The effect of barley intake depends on the host and the associated gut microbiota. This study investigated the effect of barley intake on the fecal microbiota, caecal biochemistry, and key biomarkers of obesity and inflammation. METHODS: Obese db/db mice were fed diets with and without barley during 8 weeks; lean mice were used as lean controls. Fecal microbiota was evaluated using 16S marker gene sequencing in a MiSeq instrument; several markers of caecal biochemistry, obesity, and inflammation were also evaluated using standard techniques. RESULTS: Bacterial richness (i.e., Operational Taxonomic Units) and Shannon diversity indexes were similar in all obese mice (with and without barley) and higher compared to lean controls. Barley intake was associated with increased abundances of Prevotella, Lactobacillus, and the fiber-degraders S24-7 (Candidatus Homeothermaceae) compared to both lean and obese controls. The analysis of unweighted UniFrac distances showed a separate clustering of samples for each experimental group, suggesting that consumption of barley contributed to a phylogenetically unique microbiota distinct from both obese and lean controls. Caecal butyrate concentrations were similar in all obese mice, while succinic acid was lower in the barley group compared to obese controls. Barley intake was also associated with lower plasma insulin and resistin levels compared to obese controls. CONCLUSIONS: This study shows that barley intake is associated with a different fecal microbiota, caecal biochemistry, and obesity biomarkers in db/db mice that tend to be more similar to lean controls.

Influence of whole-wheat consumption on fecal microbial community structure of obese diabetic mice.

The digestive tract of mammals and other animals is colonized by trillions of metabolically-active microorganisms. Changes in the gut microbiota have been associated with obesity in both humans and laboratory animals. Dietary modifications can often modulate the obese gut microbial ecosystem towards a more healthy state. This phenomenon should preferably be studied using dietary ingredients that are relevant to human nutrition. This study was designed to evaluate the influence of whole-wheat, a food ingredient with several beneficial properties, on gut microorganisms of obese diabetic mice. Diabetic (db/db) mice were fed standard (obese-control) or whole-wheat isocaloric diets (WW group) for eight weeks; non-obese mice were used as control (lean-control). High-throughput sequencing using the MiSeq platform coupled with freely-available computational tools and quantitative real-time PCR were used to analyze fecal bacterial 16S rRNA gene sequences. Short-chain fatty acids were measured in caecal contents using quantitative high-performance liquid chromatography photo-diode array analysis. Results showed no statistical difference in final body weights between the obese-control and the WW group. The bacterial richness (number of Operational Taxonomic Units) did not differ among the treatment groups. The abundance of Ruminococcaceae, a family containing several butyrate-producing bacteria, was found to be higher in obese (median: 6.9%) and WW-supplemented mice (5.6%) compared to lean (2.7%, p = 0.02, Kruskal-Wallis test). Caecal concentrations of butyrate were higher in obese (average: 2.91 mmol/mg of feces) but especially in WW-supplemented mice (4.27 mmol/mg) compared to lean controls (0.97 mmol/mg), while caecal succinic acid was lower in the WW group compared to obese but especially to the lean group. WW consumption was associated with ∼3 times higher abundances of Lactobacillus spp. compared to both obese and lean control mice. Analysis of weighted UniFrac distances revealed a distinctive clustering of lean microbial communities separately from both obese and WW-supplemented mice (p = 0.001, ANOSIM test). Predictive metagenome analysis revealed significant differences in several metabolic features of the microbiota among the treatment groups, including carbohydrate, amino acids and vitamin metabolism (p < 0.01, Kruskal-Wallis test). However, obese and WW groups tended to share more similar abundances of gene families compared to lean mice. Using an in vivo model of obesity and diabetes, this study suggests that daily WW supplementation for eight weeks may not be enough to influence body weight or to output a lean-like microbiome, both taxonomically and metabolically. However, WW-supplementation was associated with several statistically significant differences in the gut microbiome compared to obese controls that deserve further investigation.

A comparison of two probiotic strains of bifidobacteria in premature infants.

OBJECTIVE: To determine the impact of 2 probiotic bifidobacteria on the fecal microbiota of premature infants fed either human milk or formula. STUDY DESIGN: In the first of two phase 1 clinical trials, 12 premature infants receiving formula feedings were assigned randomly to receive either Bifidobacterium longum ssp infantis or Bifidobacterium animalis ssp lactis in increasing doses during a 5-week period. In the second, 9 premature infants receiving their mother's milk received each of the two bifidobacteria for 2 weeks separated by a 1-week washout period. Serial stool specimens from each infant were analyzed by terminal restriction fragment-length polymorphism and quantitative polymerase chain reaction for bacterial composition. RESULTS: Among the formula-fed infants, there was a greater increase in fecal bifidobacteria among infants receiving B infantis (Binf) than those receiving B lactis (Blac). This difference was most marked at a dose of 1.4 × 10(9) colony-forming units twice daily (P < .05). Bacterial diversity improved over dose/time in those infants receiving Binf. Among the human milk-fed infants, greater increases in fecal bifidobacteria and decreases in γ-Proteobacteria followed the administration of Binf than Blac. The B longum group (which includes Binf but not Blac) was the dominant bifidobacteria among the human milk-fed infants, regardless of the probiotic administered. CONCLUSIONS: Binf was more effective at colonizing the fecal microbiota than Blac in both formula-fed and human milk-fed premature infants. The combination of human milk plus Binf resulted in the greatest fecal levels of bifidobacteria.