Breast cancer is the most frequently diagnosed cancer in women worldwide. The disease and its treatments exert profound effects on an individual’s physical and mental health. There are many factors that impact an individual’s risk of developing breast cancer, their response to treatments, and their risk of recurrence. The community of microorganisms inhabiting the gastrointestinal tract, the gut microbiota, affects human health through metabolic, neural, and endocrine signaling, and immune activity. It is through these mechanisms that the gut microbiota appears to influence breast cancer risk, response to treatment, and recurrence. A disrupted gut microbiota or state of ‘dysbiosis’ can contribute to a biological environment associated with higher risk for cancer development as well as contribute to negative treatment side-effects. Many cancer treatments have been shown to shift the gut microbiota toward dysbiosis; however, the microbiota can also be positively manipulated through diet, prebiotic and probiotic supplementation, and exercise. The objective of this review is to provide an overview of the current understanding of the relationship between the gut microbiota and breast cancer and to highlight potential strategies for modulation of the gut microbiota that could lead to improved clinical outcomes and overall health in this population.

The gut microbiota plays a role in shaping overall host health and response to several cancer treatments. Factors, such as diet, exercise, and chemotherapy, can alter the gut microbiota. In the present study, the Alberta Cancer Exercise (ACE) program was investigated as a strategy to favorably modify the gut microbiota of breast cancer survivors who had received chemotherapy. Subsequently, the ability of post-exercise gut microbiota, alone or with prebiotic fiber supplementation, to influence breast cancer outcomes was interrogated using fecal microbiota transplant (FMT) in germ-free mice. While cancer survivors experienced little gut microbial change following ACE, in the mice, tumor volume trended consistently lower over time in mice colonized with post-exercise compared to pre-exercise microbiota with significant differences on days 16 and 22. Beta diversity analysis revealed that EO771 breast tumor cell injection and Paclitaxel chemotherapy altered the gut microbial communities in mice. Enrichment of potentially protective microbes was found in post-exercise microbiota groups. Tumors of mice colonized with post-exercise microbiota exhibited more favorable cytokine profiles, including decreased vascular endothelial growth factor (VEGF) levels. Beneficial microbial and molecular outcomes were augmented with prebiotic supplementation. Exercise and prebiotic fiber demonstrated adjuvant action, potentially via an enhanced anti-tumor immune response modulated by advantageous gut microbial shifts.

Snowpacks play a key role in local and regional biogeochemical cycles and impact surrounding ecosystems during snowmelt. While they do not serve as long‐term carbon sinks like glaciers or permafrost, snowpacks temporarily store nutrients, pollutants, and microorganisms that can be released into surrounding ecosystems through meltwater. Active snow microorganisms within temporary snowpacks can contribute to carbon cycling through processes such as carbon fixation, respiration, and carbohydrate metabolism. In addition, snowpacks continuously receive atmospheric inputs, including carbohydrates from plants and microbes. These carbohydrates serve as indicators of biological and human activities. Factors like season, altitude, and location affect the carbohydrate composition, with sugars like glucose, sucrose, and mannitol linked to vegetation and microbial activity, while others, such as levoglucosan, mannosan, and galactosan, trace biomass burning events. Over time, snowpacks transform into firn and eventually ice, trapping airborne particles like carbohydrates. These preserved compounds in ice cores provide insights into past environmental conditions, including vegetation patterns and fire events. However, the current situation of rapid climate change threatens to disrupt these snowpack systems, underscoring the need for urgent investigation into the dynamics of carbohydrates and microbial activity. Thus, further research is crucial to unravel the biochemical processes within snowpacks and their implications for ecosystem dynamics. Field studies and experimental approaches will be fundamental in advancing our understanding of these complex and evolving systems.

Maternal antibiotic use can increase obesity risk in offspring. Co-administering prebiotics mitigates the risk in rats. How prebiotics and antibiotics interact to affect obesity risk is unknown, but could involve altered milk microbiota that influences offspring gut colonization. Sprague-Dawley rat dams were exposed to antibiotics (low-dose penicillin) and/or prebiotics (oligofructose) during gestation and lactation. Gut and milk microbiota were measured using 16S rRNA sequencing, and metabolic measurements were taken for dams and offspring at weaning (day 21) and 10 days postweaning (day 31). Germ-free mice were transplanted with maternal cecal microbiota to assess the causal role of vertically transmitted microbiota. Offspring maternally exposed to antibiotics showed relatively accelerated taxonomic maturation in the gut pre- and postweaning. Milk composition (fat, protein, hormone, microRNA, and cytokines) was unchanged, but milk-derived bacteria differed between maternal treatments and contributed to offspring gut microbial structure. Male offspring were especially affected by maternal antibiotic exposure and had increased body weight, fat mass, caloric intake, and hepatic triglycerides by day 31. All but hepatic triglycerides were attenuated with maternal prebiotic coconsumption. fecal microbiota transplants of maternal cecal matter into germ-free mice replicated male offspring body weight and hepatic outcomes. Untargeted hepatic lipidomics and network analysis revealed strong connections between several bacteria and lipid species potentially of bacterial origin that were enriched in prebiotic offspring microbiota and livers. These data confirm the role of milk microbiota in seeding offspring microbiota and implicate maternal antibiotic-associated gut microbiota as causally implicated in compromising early-life offspring hepatic metabolism that may lead to later metabolic disorders.

The use of glacial rock flour as an agricultural soil amendment gained increasing interest due to its fine particle size, potential to deliver crop-essential nutrients, and capacity for Mg or Ca-rich silicates to enhance rock weathering to capture atmospheric CO2 in carbonate form. Additionally, some studies have observed that rock flour amendments can reduce N2O flux. Plant growth, carbon storage, and soil emissions are all influenced by microorganisms in soil, which actively participate in biotic weathering processes that release plant-essential nutrients like phosphate, potassium, and sulfur from minerals. Furthermore, microorganisms drive nitrogen and carbon cycling, which influences soil fertility and greenhouse gas emissions. Thus, the unknown impact of glacial flour application to soil microbial communities must be investigated. Our study aimed to assess a French agricultural soil microbial community responds to varying glacial rock flour application rates during a 12-week microcosm experiment. The granitic glacial flour selected for study originated from Mer de Glace (French Alps). To understand the microbial community’s response, we focused on taxonomic shifts, relative abundance of genes related to nitrogen cycling and nutrient access, and geochemical shifts between baseline and 12-week samples. We hypothesized that glacial flour amendment would select for a community that would reduce nitrogen losses through N2O and demonstrate improved ability to access flour-bound nutrients particularly at higher application rates compared to the control soil. To test this hypothesis, we conducted a 12-week microcosm study where glacial rock flour was added to 50 g of agricultural soil at rates of 0, 0.5, 2, 5, 10, 20, 30, 50, 80, 115, and 157 t ha-1. Each treatment had 12 replicates and one replicate per treatment was destructively sampled each week for analysis. For the higher application rates (30-157 t ha-1), a quartz powder control was included to account for potential changes in soil structure. Replicates remaining in the experiment were watered once per week up to 80% of water holding capacity to simulate agricultural irrigation or rainfall events. DNA was extracted from all samples for downstream analyses and subsamples from baseline and endpoint were retained for geochemical analyses. Quantitative polymerase chain reaction (qPCR) was performed on the 16S and 18S genes to quantify bacterial and fungal abundance, respectively. Metabarcoding of the v3-v4 region of the 16S rRNA gene (rrs) was done to track taxonomic changes in the bacterial population over the course of the experiment. Inorganic nitrogen species were quantified in the baseline and 12-week samples. Preliminary results showed that bacterial communities exhibited differential growth in response to amendments above 5-10 t ha-1 compared to those below, with shifts occurring at week 4 and week 10 of the experiment. Glacial flour application of 30 and 50 t ha-1 resulted in the lowest percent loss of inorganic nitrogen from baseline to week 12 compared to other application rates. These initial findings indicate that glacial rock flour application rates may significantly influence the soil microbial community, with important implications for nitrogen cycling and nutrient accessibility.

Chronic and autoimmune diseases continue to rise across Canada, demonstrating the need for sustainable dietary strategies that promote long‐term health. Fermented foods (FFs) have emerged as a potential approach, yet national data on consumption patterns and public perceptions remain largely unknown. A cross‐sectional survey of 4045 Canadian adults was conducted (September–November 2023) to assess consumption patterns, including behaviors, perceptions, and general knowledge about FFs and fermentation practices. Overall, 25.7% of participants reported consuming all 18 surveyed FFs at least once. Cheese (95.7%) and yogurt (93.2%) were the most consumed, while fermented fish (38.9%) and fermented cereals/grains (40.2%) were least consumed. Consumption patterns varied by age, sex, income, and education. Lower intake was seen in older adults, those with lower income and education, and those for whom health was not a primary consideration in food choice. Taste was the main motivator for consumption, with health second. Home fermentation was uncommon (9.0%) but more frequent among younger, more educated individuals. While there was a willingness to try new products (29.1%) and engage in home fermentation (30.0%), participants expressed uncertainty about FF safety (18.4%) and potential health benefits (52.7%). Nonetheless, two‐thirds wanted to learn more about FFs, and nearly half preferred guidance from trusted sources such as Canada's Food Guide. This study is the first comprehensive assessment of FF consumption patterns and perceptions across Canada, revealing sociodemographic trends, knowledge gaps, and opportunities to strengthen consumer education, evidence‐based resources, and future public health initiatives related to FFs.