Functional medicine: Focusing on imbalances in core metabolic processes
This medical field surveys details of assimilation, defense and repair, energy, biotransformation and elimination, transport, communication, and structural integrity, and addresses 5 lifestyle factors.
Probiotics
Probiotics are used extensively in FM, and there are very few fields in conventional Western medicine where probiotics have not been researched. Interestingly, gut microbiota (microflora) change rapidly and individually to therapeutic dietary changes, both in composition (community) and function (metabolic plasticity), implicating gut microbiota as a mediator of dietary impact on host metabolism.47 This highlights the potential for tailored probiotics to transform dietary nonresponders (eg, those who do not routinely consume a high-fiber diet) into responders whose metabolism becomes enabled to counter such conditions as obesity and type 2 diabetes.48
Caveats with probiotic administration. While the strength of recommendation for probiotic therapy is increased by their safe use in pregnancy, infants, and immunocompromised populations,49-51 various harms (ranging from mild to severe) may be underreported.52-54 In clinical practice, the effective probiotic strain(s), formulation, and dosage will vary not only by disease, but also from patient to patient, and may be dependent on nutritional factors such as vitamin D,55 diet, and even epigenetics.56
As we come to more fully recognize commensal microbiota as a major player in overall health with crosstalk in signaling pathways between intestinal bacterial and epithelial immune cells, future research is needed to help optimize probiotic dose, duration, route of administration, and whether microbial communities outperform single-species probiotics.50 Furthermore, much of a bacterial community’s effect on the host is through its metabolites, and since certain species can be used interchangeably given similar metabolic activity and function, studies to understand how prebiotics and probiotics affect the host must analyze the metabolome, in addition to the bacterial community composition.51
Alternative research methods could be informative. Similar to their limited evaluation of health outcomes in nutrition and supplement research, many RCTs examining the health benefits of probiotics often yield ambiguous results or fall short of valid conclusions because the underlying presuppositions are not met.26 For example, assuming the RCT uses a well-defined probiotic formulation, efficacy and generalizability can still be confounded by patient microbiota, diet, mucosa, immune system, and emotional status, which all affect probiotic activity/potency.50 Under these circumstances, other research methods may be more suitable or supplemental—eg, Phase II trials, epidemiologic studies, single-case experiments (n-of-1 trials) and their meta-analyses, using historical controls, preclinical studies for conceptual and theoretical development, and clinical experience.26,57-59
It is currently unknown how nonvaginal microbiota affect the health of menopausal women;63,64 and while a multicenter RCT is underway to examine a novel probiotic’s effect on menopausal symptoms and bone health, the supplemental study methods listed above could be employed as well.
Continue to: Evidence of probiotic effectiveness
