Writing in the journal Nutrition, lead author Guiseppe Puccio from University of Palermo said the study is the first to provide data on the combination of pro- and prebiotics in infant formula, and could help define the direction of the 'next generation' formulas.
"Our results show that an infant formula containing B. longum BL999 and GOS/FOS is safe and well tolerated and may improve health in full-term infants," wrote Puccio.
"These results provide direction for the development of a new generation of infant formulas that may provide health benefits to infants who cannot be breast fed," he said.
Infant formula is a highly emotive area, with watchdogs keeping a close eye on companies' marketing tactics lest they drift towards promoting their products as preferable to breast feeding.
While it is agreed that breastfeeding is the best way to ensure an infant receives the nutrients it needs in its first months, formulas are indispensable in cases where mothers are unable to feed their children - be it for health or logistical reasons. Mothers' desire to give their children the best possible start in life means that there is scope for fortification.
The latest market research on the overall baby food market, including milks and formulas, comes from Mintel, which estimates that the UK market was worth £329 million at retail in 2005.
Research and product development on the ingredient side has centred on replicating the healthy profile of breast milk as far as possible.
The scientists, including researchers from Nestlé Research Center and Nestlé Nutrition, prepared an experimental formula using Bifidobacterium longum BL999 isolated from the human gastrointestinal tract, and a prebiotic mixture containing galacto-oligosaccharides (90 per cent) and fructo-oligosaccharides (10 per cent).
"To our knowledge, there are no full publications [prior to this new study] describing the simultaneous delivery of prebiotics and probiotics to infants," said the researchers.
One hundred thirty-eight infants were enrolled for the prospective, double-blinded, reference-controlled, parallel-group, clinical trial and randomly assigned to receive either the control or experimental formula from 14 to 112 days of age.
At the end of the study, the researchers report that the symbiotic formula was associated with fewer incidences of constipation with stool characteristics that suggested good tolerability. Moreover, the results reported that symbiotic formula-fed infants showed a trend toward fewer respiratory tract infections.
"Although not statistically significant, infants in the experimental group consistently had slightly higher mean weight gain, thus underscoring the safety of the experimental formula," wrote Puccio.
The symbiotic formula-fed infants were found to have a slight but significantly increase in stool frequency, which may not be the adverse effect some might perceive, since such a frequency resembles the same situation observed with breast-fed infants, and was not associated with growth retardation or diarrhea.
"The starter formula containing BL999 and galacto-oligosaccharides/fructo-oligosaccharides is safe and well-tolerated," said the researchers.
"Infants who can not be breast fed, there may be a rationale to adapt infant formulas to promote the establishment of an intestinal microbiota resembling that of breast-fed infants. Strategies to achieve this goal include the addition of probiotics or prebiotics to formula," they said.
Source: Nutrition January 2007, Volume 23, Issue 1, Pages 1-8 "Clinical evaluation of a new starter formula for infants containing live Bifidobacterium longum BL999 and prebiotics" Authors: G. Puccio, C. Cajozzo, F. Meli, F. Rochat, D. Grathwohl and P. Steenhout