Reading and writing about epidemiological research is not my favorite, but I spotted a study on Tuesday that captured my interest as it’s in the vein of “things you can do now,” which you all know IS my favorite.
Looking to ascertain the health benefits of fermented foods on infants, Japanese researchers culled data from a nationwide study on the effects of environmental influences on the health of children (the Japan Environment and Children’s Study).[i] Moms-to-be filled in questionnaires early in their pregnancy, late in their pregnancy, and then at 1, 6 and 12 months after their babies were born. Included in the questionnaire were questions on diet (including infant consumption of yogurt and cheese) and physician-diagnosed infectious disease related to the GI tract (diarrhea, vomiting, viral gastroenteritis, rotavirus, norovirus, etc.) From a dataset of 103,062, these researchers selected 82,485 for this current study.
They found that by the time the children were a year, “…the incidence of gastroenteritis was significantly lower in infants who consumed yogurt ≥ 7 times/ week and 3-6 times/week than in infants who had yogurt <1 time/week.”[ii] Unfortunately, they did not collect data on how much yogurt was consumed per meal – just the frequency of consumption.
Eating cheese made no discernible difference in health. However, again, there was no data on the type or amount of cheese consumed. That is, it’s possible that cheese products containing no live cultures was eaten frequently, which would have no effect on the gut bacteria, or the amounts were minute.
There is, unfortunately, a lack of uniformity in so many of the studies currently in the medical literature on the benefits of probiotics or fermented foods. The paper provides several examples: one study of children aged 1-5, living in an urban slum in India, found that probiotics helped prevent acute diarrhea. Another, conducted in South Korea, showed that Bifidobacterium longum and Lactobacillus acidophilus had “…strong anti-rotavirus activity and significantly shortened the duration of the symptoms without adverse events.” Other studies, however, have found little to no effects of yogurt consumption on gastroenteritis. Of course, the amounts and strains used varied widely so there’s really no way to know for sure at this point. That is a weakness in this study as well: brands, strains, the use of supplemental probiotics, etc. – none of it was assessed. Still, as the authors write, this current study was very large, which lends it credence.
A meta-study was published in July, which reviewed the medical literature (no date restrictions) for studies on the health effects of yogurt and fermented milk products on infants.[iii] Out of 1,624 abstracts, they ended up with 10 that fit their criteria. (And they allowed in all randomized controlled trials, observational studies and and prospective cohort studies, which is a pretty broad array. The fact that they ended up with only 10 shows pretty dramatically how little work has been done in this field.) Their results: “5 of 6 studies showed a positive effect of yogurt consumption on infectious diarrhea. Two studies reported a positive effect on gut microbiota composition. Two cohort studies reported a positive effect on reducing the incidence of atopic dermatitis, one of which also reported a positive impact on food sensitivity.”
Of course you want to avoid fermented milk products that are high in sugar. But for my part, knowing what we now know about the disastrous effects of biome depletion: were I the parent of a young infant/child, I would certainly be sure that a high quality, no sugar product were a regular part of my baby’s diet.
[i] Nakamura M, Hamazaki K, Matsumura K, et al. Infant dietary intake of yogurt and cheese and gastroenteritis at 1 year of age: The Japan Environment and Children’s Study. PLoS ONE 2019 14(10):e0223495.
[iii] Donovan, SM, Rao, G. Health benefits of yogurt among infants and toddlers aged 4 to 24 months: a systemic review. Nutrition Reviews. 2019:77(7);478-486. doi: 10.1093/nutrit/nuz009.