The role of bile acids in nutritional support

Abstract

Nutritional support continues to receive much attention as a possible intervention to prevent loss of lean tissue mass, promote recovery and re-establish proper immune function in critical care patients. Yet there remains much controversy regarding the clinical efficacy of such interventions. In addition to the direct effect of nutrition in terms of micro- and macronutrient content, nutritional formulations may exert an effect via the physiological response to feeding. Here, we highlight the key role of postprandial reabsorbed bile acids in attenuating both the inflammatory response and autophagy. These observations suggest that not all patients would benefit from aggressive nutritional support.

Bile acid metabolites in early pregnancy and risk of gestational diabetes mellitus: Results from a prospective cohort study

“…First, circulating metabolites are influenced by many factors, including diet, 40 heterogeneity of populations, 41 physical behaviours, 42 assay methodology and types of biological sample, 43 environmental factors, 44 and subject nutritional status. 45 For example, fasting total taurine-conjugated bile acid levels are not associated with insulin resistance, but the change from basal to maximal postprandial levels is significantly different between women with and without insulin resistance. 38 Second, GDM is generally screened for in the third trimester, but women might have already developed impaired glucose tolerance prior to pregnancy which was not diagnosed, and there is evidence that taurine-conjugated bile acid concentrations are associated with homeostatic model assessment of insulin resistance and insulin levels.…”

“…A number of factors may contribute to inconsistent associations between TCA and GDM. First, circulating metabolites are influenced by many factors, including diet, 40 heterogeneity of populations, 41 physical behaviours, 42 assay methodology and types of biological sample, 43 environmental factors, 44 and subject nutritional status 45 . For example, fasting total taurine‐conjugated bile acid levels are not associated with insulin resistance, but the change from basal to maximal postprandial levels is significantly different between women with and without insulin resistance 38 .…”

Nutritional support in sepsis: when less may be more

“…A classic example includes the release of insulin following a meal: insulin is a canonical inhibitor of autophagy, while catabolic hormones such as glucagon (which is suppressed by feeding) induce autophagy. Similarly, we have highlighted that a key aspect of nutritional support which is seldom addressed is the physiological response to feed-fast cycles, specifically, the signalling effects of post-prandial reabsorbed bile acids [30]. For example, secondary BAs can modulate immune function via its activity on G protein-coupled bile acid receptor 1 and the Farnesoid-X-Receptor [41].…”

“…We have previously pointed out that autophagy may play a critical role in the removal of inflammogens, such as LPS, by the lysosomal enzyme, acyloxyacyl hydrolase [30]. Moreover, autophagic machinery also plays a pivotal role in pathogen clearance (known as xenophagy).…”

“…BA release following nutritional support may also impact on immune cell function, inhibiting autophagy and vascular tone (e.g. increase splanchnic blood flow) [30]. Similarly, a recent expert consensus have pointed out the emerging role of intestinal biota in a critical care setting [43].…”