Issue 06 · 17 August 2026
Six studies from the first half of August. The birth canal loses most of the credit for an infant's first bacteria, ten days of heat training deliver everything except the two things it is usually done for, and a creatine trial that the authors themselves refuse to let you read as a brain result.
Issue 06: Credit in the wrong place
17:33 · 17 August 2026
In this issue
Dutch researchers sequenced 4,526 stool samples from 714 mother and infant pairs, from twelve weeks of pregnancy to the baby's first birthday, and matched bacterial strains between them. The mother's own gut was the major reservoir for the infant's gut strains, with only occasional transmission from the vaginal or breast milk microbiomes. Home birth barely registered, mattering about as much as how long the pushing stage lasted.
Nature · Sinha et al. · University of Groningen and University Medical Center Groningen · 12 August 2026 · PMID 42587158
Twenty six men and women did ten days of fixed workload exercise in a hot chamber. They adapted in all the usual ways, running cooler with lower heart rates and more sweat. But blood plasma volume held steady and maximal oxygen uptake did not move, which are the two changes heat training is often expected to deliver.
American Journal of Physiology, · Greenfield et al. · US Army Research Institute of Environmental Medicine · 7 August 2026 · PMID 42566767
Sixty four adults aged 45 to 65 took creatine or a matched placebo for twelve weeks, some alongside an exercise and weight loss programme and some without. Creatine increased lean tissue mass and strength in both settings. The cognitive and blood marker results, which are the ones currently driving the supplement's marketing, are labelled exploratory by the authors themselves.
Journal of the International · Chun et al. · Texas A and M University · 11 August 2026 · PMID 42578920
Rather than treating ultra-processed food as one category, German researchers broke it into nine groups of specific additives and followed 101,560 UK Biobank participants for a median of ten and a half years. Only four of the nine additive categories tracked with new hypertension. Five showed no association at all, and three specific additives ran the other way.
European Heart Journal · Krost et al. · Justus-Liebig University of Giessen · 3 August 2026 · PMID 42545878
Among 5,301 US adults aged 55 and over followed for about nine years, a low-carbohydrate eating pattern tracked with lower dementia risk and a low-fat one did not. But splitting each pattern by food quality reversed the picture within it: plant based and higher quality versions tracked with less dementia, animal based and lower quality versions with more. Inherited risk did not change the pattern.
The American Journal of · Chen et al. · Zhejiang University School of Medicine and Harvard T.H. Chan School of Public Health · 7 August 2026 · PMID 42567320
Muscle biopsies from 107 women aged 19 to 70 show that the main estrogen receptor in skeletal muscle is about half as abundant in the oldest group as in the youngest, and that receptor levels track proteins governing nitric oxide and oxidative balance. Everything measured here is protein abundance. No oxidative stress outcome and no muscle function outcome was measured at all.
GeroScience · Tamariz-Ellemann et al. · University of Copenhagen · 7 August 2026 · PMID 42566157
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