Environmental scientist and long-time campaigner against soy-based infant formulas, Dr Mike Fitzpatrick, has warned about the risk of thyroid disease in infants fed soy formulas, high soy consumers and users of isoflavone supplements:
"There is potential for certain individuals to consume levels of isoflavones in the range that could have goitrogenic effects. Most at risk appear to be infants fed soy formulas, followed by high soy users and those using isoflavone supplements".
The report noted that infants fed soy formulas are exposed to high levels of isoflavones, which are potent anti-thyroid agents, and that the risks to normal growth and development were significant.
Fitzpatrick stated that thyroid problems due to soy might not be recognised "due to difficulties in establishing a cause and effect relationship" and noted that even experienced soy researchers may be ignorant of the connection between isoflavones and goitre.
Fitzpatrick also rejected claims that there was no evidence that isoflavones in soy formulas harmed infants citing the reported cases of goitre that have occurred in infants fed iodine sufficient soy formulas.
Fitzpatrick stated his support to the position of the New Zealand Ministry of Health:
"The Ministry of Health has found that infants with a history of thyroid dysfunction should avoid soy formulas and soy milks. Additionally, there is potential for isoflavone exposure to cause chronic thyroid damage in all infants fed soy formulas" Fitzpatrick stated that exposing infants to isoflavones was unnecessary and that the risk of harm could be avoided if manufacturers removed isoflavones from soy formulas. "In the interim" he stated "it is appropriate for medical practitioners to monitor the thyroid status of infants fed soy formulas"
Fitzpatrick also claimed that high soy consumers and users of isoflavone supplements were also at risk of thyroid disorders. He stated that the subtle effects of anti-thyroid agents on thyroid function would most likely be evidenced as subclinical, or even overt hypothyroidism.
Fitzpatrick also noted that a sporadic pattern of soy use may also not be without risk since the resulting thyroid stimulation parallels the classic method for inducing thyroid tumours in laboratory animals. He recommended "a more cautionary approach to the use of soy and isoflavone supplements".
New Zealand Medical Journal (Volume 113, Feb 11, 2000)
Folks, soy formula is one of the worst foods that you could feed your child. Not only does it have profoundly adverse hormonal effects as discussed above, but it also has over 1000% more aluminum than conventional milk based formulas.
I don't recommend either, but if one, for whatever reason, cannot breast feed, then Carnation Good Start until six months and Carnation FollowUp after that seem to be the best commercial formula currently available. The milk protein is hydrolyzed 80% which tends to significantly decrease its allergenicity.
It is also important to note that when breast feeding it is wise to avoid drinking milk as it has been shown for several decades that the milk will pass directly into the breast milk which can cause potential problems in the infant.