Nutrient availability, the microbiome, and intestinal transport during pregnancy

Abstract

Adequate adaptation of the gastrointestinal tract is important during pregnancy to ensure that the increased metabolic demands by the developing fetus are met. These include changes in surface area mediated by villus hypertrophy and enhanced functional capacity of individual nutrient receptors, including those transporting glucose, fructose, leucine, and calcium. These processes are regulated either by the enhanced nutrient demand or are facilitated by changes in the secretion of pregnancy hormones. Our review also covers recent research into the microbiome, and how pregnancy could lead to microbial adaptations, which are beneficial to the mother, yet are also similar to those seen in the metabolic syndrome. The potential role of diet in modulating the microbiome during pregnancy, as well as the potential for the intestinal microbiota to induce pregnancy complications, are examined. Gaps in the current literature are highlighted, including those where only historical evidence is available, and we suggest areas that should be a priority for further research. In summary, although a significant degree of adaptation has been described, there are both well-established processes and more recent discoveries, such as changes within the maternal microbiome, that pose new questions as to how the gastrointestinal tract effectively adapts to pregnancy, especially in conjunction with maternal obesity.

Cadmium exposure during pregnancy and lactation: materno-fetal and newborn repercussions of Cd(ii), and Cd–metallothionein complexes

“…[1][2][3] The physiological changes that occur during pregnancy, such as an increased respiratory rate or alterations in the gastrointestinal system in order to meet the nutritional needs during embryo/fetus development, facilitate the absorption of Cd. 37,38 At the molecular level, its toxicity can reduce Zn transport from the mother to the fetus/newborn, induce MT gene expression in specific tissues 32 or displace the Zn in the Zn-MT complexes to form Cd-MT complexes. 39,40 These modifications alone or in combination threaten both good materno-fetal and newborn health.…”

Cadmium Handling, Toxicity and Molecular Targets Involved during Pregnancy: Lessons from Experimental Models

“…This effect can be explained by the physiological changes that take place during this stage, like increased respiratory rate, decreased gastrointestinal motility and decreased gastric emptying [ 40 ]. In addition, the overexpression of receptors and transporters in the gut due to high nutrient demand [ 41 ] can promote Cd absorption too. Cadmium accumulates in the lung or gut depending on the route of exposure; then, it is distributed to the liver, kidneys, placenta, mammary glands, uterus and fetus [ 42 , 43 , 44 , 45 ] and it can be excreted into the milk [ 46 , 47 ].…”

Gut Dysbiosis in Animals Due to Environmental Chemical Exposures

“…As illustrated in Figure 1 , the gut microbiome changes could thus be secondary to phenotypic changes in the host, including metabolic disorders (obesity/weight loss, inappetence, gastrointestinal disorders, and growth defects to list a few examples). For instance, obesity, starvation, and gastrointestinal disorders could directly affect nutrient substrate availability within the gastrointestinal system and thereby shift proliferation to certain bacterial communities (Sweeney and Morton, 2013 ; Astbury et al, 2015 ; Remely et al, 2015 ; Jonkers, 2016 ; Nettleton et al, 2016 ; Hoffman et al, 2017 ; Seganfredo et al, 2017 ). Some of the environmental chemicals discussed below, namely bisphenol A (BPA), are associated with inducing metabolic disorders and obesity, and are therefore considered obesogens (Johnson et al, 2015 ; Janesick and Blumberg, 2016 ; Heindel et al, 2017 ).…”