Researchers analyzed three public gut-microbiome datasets that together cover 24 populations across four continents. The samples included hunter-gatherers and pastoralists in Botswana, Tanzania and Nepal; rural farmers in Malawi and Venezuela; and urban residents in Philadelphia and St. Louis. One dataset also compared breastfed and formula-fed infants.
Prior studies show inactive estrogen goes into the intestine, where microbes break it down and can reactivate it so the body reabsorbs it. The study examined the estrobolome, the group of gut microbes that do this. It found that microbiomes in industrialized populations recycle more discarded estrogen than those in non-industrial populations, and formula-fed infants showed higher recycling capacity than breastfed infants. The researchers say early life and daily environments may change lifetime hormone exposure.
Difficult words
- gut-microbiome — microbes living in the human digestive tract
- estrobolome — gut microbes that change discarded estrogen
- intestine — part of the body for digestion and absorption
- estrogen — a natural hormone in the body, especially in women
- reactivate — make active again after a period of inactivity
- formula-fed — babies fed with manufactured milk, not breast milk
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- How could early life and daily environments change a person's hormones?
- Why might formula-fed and breastfed infants have different microbiomes?
- Do you think where people live (rural or urban) can change their gut microbes? Why?
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