In yet another finding that points out the positives of breastfeeding, scientists report that beneficial fungi and yeasts reside in breast milk.
Previous studies have found bacteria in breast milk, and certain fungi and bacteria are known to be important for infant health.
Seeding of fungal species
The researchers found yeasts and other fungi in breast milk from mothers in Spain, Finland, China and South Africa, showing that this occurs in women who live in regions with different weather, diets and lifestyles.
The study was published in the journal Applied and Environmental Microbiology.
"Our research demonstrates the presence of yeasts and other fungi in breast milk in healthy mothers, supporting the hypothesis that breast milk is an important source of microorganisms to the growing infant," said principal investigator Maria Carmen Collado. She is a senior researcher at the Institute of Agrochemistry and Food Technology at the National Research Council in Valencia, Spain.
"Our data confirm the presence of fungi in breast milk across continents and support the potential role of breast milk on the initial seeding of fungal species to the infant gut," Collado said in a journal news release.
"This supports the existence of a 'breast milk mycobiota' under healthy conditions," she said.
Influence of environmental factors
Malassezia and Davidiella were most common fungi among breast milk from the different countries, and Sistotrema and Penicillium were also present in breast milk from women in each country.
However, there were notable differences in milk from different regions. The researchers found that more than 70% of breast milk samples from Spain and South Africa had detectable levels of fungal DNA, compared with only 45% of Chinese samples and only 35% of Finnish samples.
"Our findings reinforce the potential influence of environmental factors, in particular geographic location, on the species of yeast and fungi that make up the breast milk mycobiome," Collado said.
She pointed out that some yeasts are currently used as probiotics to promote good health in infants.
"The most common one is Saccharomyces boulardii. Our study identifies more fungal species that could potentially confer benefits for human health, and the possibility of isolating appropriate strains from breast milk. Those potential benefits should now be studied in detail," Collado said.
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