The gut microbiota (GM) is an important regulator of body homeostasis, including intestinal and extra-intestinal effects. This review focuses on the GM-bone axis, which we define as the effect of the gut-associated microbial community or the molecules they synthesize, on bone health. While research in this field is limited, findings from preclinical studies support that gut microbes positively impact bone mineral density and strength parameters. Moreover, administration of beneficial bacteria (probiotics) in preclinical models has demonstrated higher bone mineralization and greater bone strength. The preferential bacterial genus that has shown these beneficial effects in bone is Lactobacillus and thus lactobacilli are among the best candidates for future clinical intervention trials. However, their effectiveness is dependent on stage of development, as early life constitutes an important time for impacting bone health, perhaps via modulation of the GM. In addition, sex-specific difference also impacts the efficacy of the probiotics. Although auspicious, many questions regarding the GM-bone axis require consideration of potential mechanisms; sex-specific efficacy; effective dose of probiotics; and timing and duration of treatment.

Diets rich in fruits and vegetables (FV) have been associated with a reduced risk of chronic disease, including cardiovascular disease. Unfortunately, public health campaigns to increase FV intake have had limited success. A number of mixed concentrated FV products have been studied, which may help certain individuals improve nutrient status. However, the possible health benefits of FV supplements have not been systematically reviewed. We, therefore, undertook a systematic search of MEDLINE and EMBASE to identify clinical interventions that examined the effect of commercially available concentrated mixed FV supplements on cardiovascular disease risk factors. Twenty-two reports, which used commercially available products, were identified. None of the studies reported any serious adverse effects. Overall, daily consumption of FV supplements significantly increased serum concentrations of the major antioxidant provitamins and vitamins found in plant foods (β-carotene, vitamins C and E) and folate. Functional changes, such as reduced serum homocysteine and markers of protein, lipid, and DNA oxidation, were also reported; in addition, the health advantages on markers of inflammation, immunity, and endothelial function are promising. Limitations of the available studies were related to the diversity of studies conducted with respect to design and study population and the variability in the measured outcomes and assays utilized. While mixed FV supplements may serve as an efficacious complement for individuals who have difficulty achieving their daily FV intake requirement, further research on additional retail preparations is warranted. Key teaching points: Mixed fruit and vegetable supplements produced from plant foods may serve as an efficacious complement to the habitual diet in individuals who have suboptimal intake or variety of nutrient-dense fruits and vegetables. Current research indicates that fruit and vegetable concentrates significantly increase serum levels of antioxidant provitamins and vitamins (β-carotene, vitamins C and E) and folate and reduce homocysteine and markers of oxidative stress. Mechanistic studies and larger, randomized, placebo-controlled double-blind trials in both healthy and high-risk populations are necessary to better understand the health effects of these supplements.

Maternal dietary vitamin D beneficially programs intestinal permeability and systemic LPS concentration, which is accompanied by stronger trabecular bone in an obesogenic environment. Thus, the gut may mediate vitamin D effects. Moreover, optimizing vitamin D in early life may be critical for later health.

Our findings suggest that low vitamin D exposure results in an inflammatory-prone status that may contribute to or be a risk factor for several diseases including inflammatory bowel disease, obesity, diabetes, and cardiovascular diseases.

Bifidobacterium bifidum MIMBb75 is a recently identified probiotic. However, its distribution along the intestine and impact on resident microbiota is unknown. Herein, we established a quantitative real-time polymerase chain reaction assay targeting the B. bifidum-specific BopA region for the quantification of B. bifidum in feces and used this assay to investigate transit of B. bifidum MIMBb75 through the murine intestine. We also analyzed the consequential impact on resident microbial cohorts. C57BL/6J mice were daily gavaged with 0.2 mL of either sterile PBS or PBS containing 10(8) colony-forming units of B. bifidum MIMBb75 for 2 weeks, after which intestinal contents and fecal samples were analyzed for microbial compositional changes. Bifidobacterium bifidum MIMBb75 was able to transiently colonize the murine intestine, with the predominant niche being the ceco-proximal colonic region. Region-specific effects on host microbiota were observed including decreased levels of Clostridium coccoides in the cecum, increased levels of bifidobacteria in the proximal and distal colon, total bacteria and Clostridium leptum in the proximal colon, and of C. coccoides in the feces. These findings suggest that probiotic properties of B. bifidum MIMBb75 may partially depend on its ability to at least transiently colonize the intestine and impact on the resident microbial communities at various intestinal loci.