September 22-23, 2014, a symposium* titled “Probiotics Throughout the Lifespan” was held at the Harvard Medical School Campus. It featured an impressive array of speakers from the microbiome and probiotic fields. Sessions matched key lifespan periods: pregnancy, infancy, adulthood and elderly. If you missed the meeting, it was webcast and will be available to view in upcoming weeks.
Probiotics are often seen as agents that can optimally function when taken during windows of opportunity across the lifespan. These ‘windows’ often correspond to periods of microbiome instability, such as during pregnancy, infancy and old age. Other periods of instability include during antibiotic or other drug use, when diseased and perhaps less dramatically during dietary and lifestyle changes.
I was most intrigued by the session on pregnancy. Probiotics administered to a pregnant woman have the potential to positively impact the health of both the soon-to-be born infant and the mother. Promising areas for probiotics administered to pregnant women with a subsequent impact on their children include:
Reduction of risk of atopic dermatitis, asthma, food allergy and infections (common colds, otitis, fever). One speaker reviewed observational studies that revealed a profound protection of the child from allergic and infectious diseases when the pregnant mother was exposed to environmental stimuli such as farms, cow sheds and consuming raw milk.
Obesity. The microbiota is clearly linked to obesity. The field lacks causal studies to date, but potential remains that microbiota-based interventions during pregnancy could impact the risk of children becoming overweight.
Reducing preterm birth and complications thereof, including necrotizing enterocolitis (NEC). Evidence exists that administration of probiotics to the premature infant can reduce the risk of developing NEC, and thereby morbidity and mortality associated with the onset of the disease. No studies to date have explored the possibility that administration of probiotics to the pregnant mother can impact prematurity or the onset of NEC. Mechanistically, the emerging evidence of a placental microbiome provides a means for exposure of pregnant women to probiotics (or environmental microbes) to impact health of the next generation.
Much less information is known about the impact of probiotics on the pregnant woman, but it is clear that microbiota changes occur during pregnancy. Also, a pregnant woman often expresses symptoms of metabolic syndrome, such as increased blood glucose, increased serum insulin and increased insulin resistance. Promising areas for probiotic intervention can be hypothesized, such as decreasing some symptoms experienced during pregnancy such as morning sickness or improving gestational diabetes.
The speakers in this session agreed that best way to realize the potential for probiotics during pregnancy is through human trials, appropriately designed, conducted and reported. Although probiotic strains destined for clinical trials must be fully characterized, it is not clear what tests could predict clinical success. Therefore, evidence of a health benefit likely needs to precede mechanistic studies.
Finally, probiotic strains of the future may be different from the familiar lactobacilli, bifidobacteria and yeast used today. Some native colonizing microbes associated with healthy people have been shown to promote a healthy immune response and result in healthy metabolic outputs. Such microbes may comprise the probiotics of the future. One such example described at this symposium is Eubacterium hallii, a microbe associated with improved insulin sensitivity. This microbe is currently being tested in The Netherlands in human trials as a novel therapeutic for insulin resistance.
*The symposium was sponsored through unrestricted educational grants provided by Danone Nutricia Research and Yakult.