Adding a probiotic supplement to formula milk slashed rates of respiratory infections in babies who werenāt breastfed. , but the supplement ā which contained both sugars from breast milk and the bacteria needed to ferment them ā produced fatty molecules that seemed to strengthen the infantsā immune systems. This helped them eliminate viruses that cause symptoms like sneezing and a runny nose.
āItās phenomenally exciting,ā says at Imperial College London, who wasnāt involved in the research. A high burden of early-life infections has been and an . āModifying formula milk to help set up good immune health for babies is a really powerful concept,ā says Davis.
However, such interventions could have unintended consequences, including actually increasing the risk of allergies. āIf you increase the power of someoneās immune response against infections, that might make them more likely to be susceptible to allergies or autoimmunity,ā says Davis, who learned about the supplement at the conference at the Royal Society in London on 12 October. āThese interventions are likely to have both pros and cons; we donāt know what those all are yet.ā
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Prior trials suggest that supplements containing sugars from breast milk, called human milk oligosaccharides (HMOs), in such infants. These sugars are fermented by gut bacteria, including Bifidobacterium longum infantis, to produce short-chain fatty acids, molecules that seem to enhance immune responses against pathogens like viruses and bacteria.
But some babies, especially those in Western nations, lack B. longum infantis in their guts, which may be related to their motherās diet. Previously, at Imperial College London and his colleagues found that supplements that boost levels of this bacterium immune health in breast-fed babies.
Now, Brodinās team has developed a supplement containing both HMOs and B. longum infantis and tested it on formula-fed babies, who are more likely to lack B. longum infantis.
With funding from NestlĆ©, which develops formula milk, the researchers recruited 223 infants ā aged between 2 and 5 weeks ā who were exclusively formula fed in Manila, the Philippines. About half of the infants were randomly assigned to drink formula milk made from a powder containing the probiotic supplement, while the remaining infants consumed the same milk without the supplement.
The parents ā who were blinded as to which group their baby was in ā logged whenever they showed symptoms of respiratory infections, such as sneezing, coughing or a runny nose, until they were 6 months old.
During this time, 23 per cent of the infants in the supplement group were recorded as developing an infection, compared with 40 per cent in the formula-only group. The former infants also recovered a few days faster from the infections, on average. āThe respiratory infections were fewer and their duration was shorter,ā says Brodin.
Further analysis of stool samples revealed that the supplement seems to boost levels of B. longum infantis in the gut, while reducing inflammation and supporting immune responses against pathogens.
The researchers need to carry out large trials that track the supplementās effects in different countries over time, says Davis. Brodin says the team is planning to explore how it affects the risk of allergies and asthma.
