Children are vulnerable to diet inadequacies, which may affect immune function. Our objective was to determine if a follow-up formula (FUF) containing DHA, the prebiotics PDX and GOS, and yeast β-glucan affects incidence of respiratory infections and diarrheal disease in healthy children.

In a double-blind, randomized, controlled, prospective trial, 3-4 year old children were fed 3 servings per day of either a FUF with 25 mg DHA, 1.2 g PDX/GOS, and 8.7 mg yeast β-glucan per serving or an unfortified, cow's milk-based beverage (control) for 28 weeks. Fecal and blood samples were collected to assess immune markers and iron/zinc status. Incidence of acute respiratory infections (ARI), diarrheal disease, and antibiotic treatment were obtained from medical records.

The FUF group had fewer episodes and shorter duration of ARI (mean days [SE]; control = 4.3 [0.2]; FUF = 3.5 [0.2]; P = .007), less antibiotic use (n [%]; control = 21 [14%]; FUF = 8 [5%]; P = .01), and fewer missed days of day care due to illness. No diarrheal disease was diagnosed in either group. The FUF group had higher interleukin-10 and white blood cell count at the end of the study. There were no differences in hemoglobin, serum ferritin and zinc, or fecal secretory immunoglobulin A.

Daily consumption of a FUF was associated with fewer episodes and shorter duration of ARI, as well as less antibiotic use. The children who consumed the FUF had increased interleukin-10 and white blood cells, suggesting an antiinflammatory mechanism and/or an increase of effector immune cells.