Widespread use of soy-based formula without clinical indications

In view of reports of the growing popularity of soy-based formula for infants, we examined soy consumption and its possible overuse during early infancy in central Israel.

Mothers of 1,803 infants aged 2, 4, 6 and 12 months attending well-baby clinics participated in a telephone survey covering background data, rate, duration, and pattern of soy-based formula use and the reasons for its initiation. The reasons were grouped into those based on the recommendations of the medical personnel and those based on mothers' initiative, and evaluated according to infants' age at soy-based formula initiation (0 to 1, 2 to 4 and 5 to 12 months). The symptoms that prompted soy-based formula use were assessed quantitatively.

The rate of soy-based formula use was 10.4% at 2 months and 31.5% at 12 months (P<0.001); 70.6%+/- 2.7% of the infants were given soy for>6 months. Regardless of infants' age, the role of the mothers in the decision to use soy-based formula was greater than that of the medical personnel, and increased significantly with age (chi for trend=0.018). A suspicion of cow's milk allergy was responsible for only 10.9% (7/64) of all soy initiations in infants aged 5 to 12 months. In all ages, occasional symptoms, mainly diarrhea (33.3%) and colic (19.8%), were the leading cause for recommending soy-based formula by medical personnel, whereas the personal preference without clinical justification was the leading cause among mothers.

The use of soy-based formula in central Israel is extensive and continues for long periods, with rates far beyond clinical indications. Mothers play a greater role than medical personnel in the decision to initiate soy-based formula.