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The Right Formula?

Soy Milk vs. Cow's Milk

Going too far? continued...

If soy formulas caused problems, Setchell says, physicians would have noticed it by now. Soy milk has been given to infants for centuries in Asian countries, according to the AAP, and in this country since 1909.

Setchell's views are supported by British pediatrician Charles Essex, MD, who wrote in the Aug. 31, 1996, British Medical Journal that there is virtually no data on the effects of phytoestrogens on children. He also noted that pediatricians have not reported large numbers of male infants developing breasts or other female traits because of soy formula. Still, he acknowledged that the long-term effects of soy are not known.

Comparing formulas

Nutritionally speaking, soy and cow's milk formulas are similar. Both include vitamins A, D, E, and K. The main difference is in their protein and sugar make-up.

Cow's milk is processed into formula by heating and other methods that make the animal proteins in the milk more digestible. Supplemental milk sugar (lactose) is added to mimic the higher sugar content of breast milk. Finally, the fat (butterfat) is removed and replaced with vegetable oils or animal fats, which are also easier to digest.

Soy formulas, which contain plant proteins and glucose or sucrose (rather than lactose), have changed greatly since they were first introduced. In the past, they included soy flour, which led to diarrhea, excess gas, and fussiness. Today, the formulas contain a soy protein isolate, which reduces the frequency of gastrointestinal problems.

The quality of protein in cow's milk formulas is a bit better than that in soy, but neither type is as good as that in breast milk, says the AAP. And lactose-free cow's milk formulations are now available for infants that are lactose intolerant.

The bottom line

There's clear consensus among most pediatricians that breast is best. The AAP recommends breast milk for the first 12 months if possible. Short of that, it recommends cow's milk formula as a first choice and soy as an alternative for vegans. But Essex also notes that if an infant is thriving on soy formula, parents should probably leave well enough alone.

Lori Oliwenstein-Kluger says she is comfortable with her choice. Today, 3-year-old Emily is doing well, but Lori will soon revisit the formula decision -- her son is due in January. Will she give him soy milk as well? She admits to some moments of doubt, wondering if the phytoestrogens might cause some hormonal problems. But her pediatrician has helped quell those concerns, and she now plans to breastfeed as long as possible, then switch him to a soy-based formula.

And her pediatrician thinks that's a fine plan.

Kathleen Doheny is a Los Angeles journalist and a contributing editor for WebMD. She also writes for Shape, Working Woman, and Fit Pregnancy magazines and The Los Angeles Times.


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