Lactose in formula and gut bacteria in allergic infants
What it found
In infants with cow's milk allergy, adding lactose to a special formula increased helpful gut bacteria and short-chain fatty acids, and lowered other bacteria to levels seen in healthy infants.
The study was in people.
What they found
Studies in people
Helpful bacteria increase
Adding lactose significantly increased the counts of Bifidobacteria and lactic acid bacteria in the stool.
Other bacteria decrease
Adding lactose significantly decreased Bacteroides and clostridia, bringing their counts down to levels found in healthy infants.
Short-chain fatty acids rise
Lactose significantly increased the total concentration of short-chain fatty acids, especially acetic and butyric acids.
What the authors conclude
“The addition of lactose to an extensively hydrolyzed formula is able to positively modulate the composition of gut microbiota by increasing the total fecal counts of Lactobacillus/Bifidobacteria and decreasing that of Bacteroides/Clostridia.”
Also in their conclusions
- They conclude that adding lactose to an extensively hydrolyzed formula can positively change the gut bacteria by increasing Lactobacillus and Bifidobacteria and decreasing Bacteroides and Clostridia.
- They say this positive effect is completed by an increase in short-chain fatty acids, especially acetic and butyric acids.
How it was done
Allergic infants tend to have different gut bacteria, with fewer helpful types and more harmful ones. The special formula used to treat them has no lactose, which may affect gut bacteria.
Infants with cow's milk allergy were given a special formula without lactose for 2 months, then the same formula with lactose for another 2 months. Healthy infants of similar age and sex were used for comparison. Stool samples were tested before and after lactose was added.
What it can’t tell you
- We summarised it from the abstract only.
- This was a small study in infants with cow's milk allergy, so the results may not apply to other groups.
- The study only looked at gut bacteria and their products, not at symptoms or long-term health.
Who paid
- Authors work at
- University of Bari Aldo Moro, Italy
The paper
- Title
- Effect of lactose on gut microbiota and metabolome of infants with cow's milk allergy
- Type
- Clinical trial
- Evidence
- Studies in people
- Summarised from
- Abstract only
- Cite
- Francavilla R, Calasso M, Calace L, et al (2012). Effect of lactose on gut microbiota and metabolome of infants with cow's milk allergy. Pediatric allergy and immunology. doi:10.1111/j.1399-3038.2012.01286.xPubMed 22435727DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error