文章基本信息

标题：Known Contaminants Found in Infant Formula
作者：Marsha Walker
期刊名称：Mothering
印刷版ISSN：0733-3013
出版年度：2000
卷号：May-June 2000
出版社：Mothering Magazine

Known Contaminants Found in Infant Formula

Marsha Walker

Mothers are sometimes worried about or have been discouraged from breastfeeding because of concerns regarding toxins found in the body and transferred to the baby through lactation. However, infant formula is full of pollutants that carry a great potential to harm. The infant formula industry would prefer we not know this; indeed, these "ingredients" are not listed on the labels. We can make an informed decision about what we choose to feed our infant with a look at a few of the unlisted and hidden components.

Aluminum, which is present in soybeans and other additives used to make formula, interferes with cellular metabolic processes and information transfer from DNA. Aluminum is found in very high concentrations in soy formula, some of the hypoallergenic formulas, and some of the preterm infant formulas. This is of concern because of the possibility of increased amounts of aluminum being deposited into the brain and the resulting risk of brain dysfunction. Standard formulas can contain up to 40 times the amount of aluminum found in breastmilk. There are fewer than 5 to 45 ug/l (micrograms per liter) in breastmilk. However, there are 557 to 2,346 ug/l in soy formula.[1,2,3]

Silicon, like aluminum, exists in soybeans and some of the additives used in formula manufacture. While silicon can be detected in the milk of women with silicon breast implants, the amount of silicon found in formula is significantly higher. If a woman has silicone implants, 55.45ng/ml (nanograms per milliliter) of silicon (a proxy for silicone) can be found in her milk. In mothers who did not have breast implants, approximately 51.05ng/ml of silicon was present in the breastmilk. Twenty-six brands of formula have been tested for silicon, however, and the levels were significantly higher: from 746 to 13,811 ng/ml. We still do not know the effect of large amounts of silicon on an infant.[4]

Several brands of formula have tested positive for genetically engineered corn and soy. We know today that 55 percent of the US' soy crop and 35 percent of the corn crop is currently genetically engineered. Neocare and Isomil products, Ross Labs' Similac, Carnation's Alsoy product, and Mead Johnson's ProSoBee formula all tested positive for GE ingredients. GE ingredients pose the risk of introducing novel toxins, new allergens, and an increased antibiotic resistance to infants. Because the FDA does not require labeling of GE foods, parents will remain unaware that their baby is consuming transgenic ingredients.

MSG (monosodium glutamate, or processed free glutamic acid and processed free aspartic acid) is a known neurotoxin found in a number of infant formulas. Because the blood brain barrier is not fully developed in infants, these neurotoxins are more accessible to the infant brain than the adult brain. The highest levels of these neurotoxins were found in hypoallergenic formulas. Because no studies have been done on the long-term outcomes of infants fed on hypoallergenic formulas, it's unknown if they will exhibit more learning disabilities at school age, and/or more endocrine disorders such as obesity and reproductive disorders later in life.[5]

Phytoestrogens are endocrine disruptors found in soybeans. Infants fed soy formula have circulating phytoestrogen concentrations that are 13,000 to 22,000 times higher than levels normally found in early life. These bioactive compounds can create steroid hormone imbalance, compete with enzymes that metabolize steroids and drugs, and can affect gonadal (sex organ) function. Soy formula has, for example, been linked to premature thelarche (breast development in infants and girls under eight years of age). Phytoestrogens (isoflavones) also have an effect on the thyroid gland. They're well-known inducers of goiter and antithyroid agents. They act against the thyroid by inhibition of thyroid peroxidase. Children with autoimmune thyroid disease were three times more likely to have been fed soy formula in infancy. [6,7,8]

There are additional health considerations associated with bottle-feeding itself, independent of formula, and having to do with the possibility of leaching from the plastic bottle into the formula, which is then ingested by the baby. These include phthalates and bisphenol-A, industrial chemicals that disrupt the endocrine system. Phthalates, used as plasticisers (plastic softeners) are testicular toxins (capable of disrupting the growth, development, and function of the testes) as well as estradiol imitators (capable of disrupting the hormone system).

Bisphenol-A, used in the production of polycarbonate plastics and also sometimes detected in plastic baby bottles, can leach from the container. Since 1938, it has been identified as an estrogenic inducer (capable of reducing sperm counts in men and increasing the risk of breast cancer in women). Bisphenol-A resins are also used as lacquers to coat metal products such as food cans. Because it has a high affinity for fatty products, bisphenol-A has been shown to leach into the content of cans during the autoclaving (heating for sterilization) process, and has thus been found in cans of milk-based infant formula.

While a lot of people believe that contaminated water supplies exist only in developing nations, municipal water systems in the US and the pipes that carry water are a source of numerous contaminants. Water from wells can also pose a significant risk if not tested for lead, arsenic, nitrates, and other chemicals used in agriculture. If lead is present in the supply, and the water is used from the hot tap or boiled, for example, this serves to concentrate the lead and contribute to elevated blood lead levels in the infants who consume it. There is a six point IQ drop for every 10ug increase in blood lead levels.[9]

Formula reconstituted with nitrate- contaminated water puts infants at risk for potentially fatal methemoglobinemia. The baby converts nitrates to nitrites, which results in the infant's hemoglobin being converted to methemoglobin. Methemoglobins can't bind molecular oxygen; thus a baby would develop an inability to circulate oxygen and turn blue. This risk increases if babies under six months are also fed baby food that contains high concentrations of nitrates, such as green beans and bananas. [10, 11, 12]

Atrazine, a weed killer that can enter the water supply, causes mammary and uterine cancer in rats. In the cities and towns with the worst tap water contamination, formula-fed babies who consume reconstituted formula would receive a lifetime dose of this chemical in the first four months of their lives. The states with high levels of atrazine in many community water systems are Ohio, Indiana, Illinois, Iowa, Missouri, Nebraska, and Kansas.[13]

If you'd like to check your water system for contamination, consult the Environmental Working Group's website, www.ewg.org. Or contact your local city or town water department for a report on lead and other contaminant levels. All homes should be checked for lead pipes and lead-soldered pipes, which should be replaced if found. The Environmental Protection Agency (EPA) can also provide further details on water contamination.

Notes

[1.] W. W. K. Ko, L. A. Kaplan, and S. K. Krug-Wispe, "Aluminum Contamination of Infant Formulas," Journal of Parenteral and Enteral Nutrition 12 (1988): 170-173.

[2]. R. Weintraub, G. Hans, M. Meerkin, and A. Rosenberg, "High Aluminum Content of Infant Milk Formulas," Archives of Disabled Children 61 (1986): 914-916.

[3.] N. M. Hawkins, S. Coffey, M. S. Lawson, and H. T. Delves, "Potential Aluminum Toxicity in Infants Fed Special Infant Formula," Journal of Pediatric Gastroenterological Nutrition 19 (1994): 377-381.

[4.] J. L. Semple et al., "Breast Milk Contamination and Silicone Implants: Preliminary Results Using Silicon as a Proxy Measurement for Silicone," Plastic and Reconstructive Surgery 102 (1998): 528-533.

[5.] truthinlabeling.org/formula.htm.

[6.] K. D. Setchell, L. Zimmer-Nechemias, J. Cai, and J. E. Heubi, "Exposure of Infants to Phyto-Oestrogens from Soy-Based Infant Formula," The Lancet 350 (1997): 23-27.

[7.] C. H. Irvine, M. G. Fitzpatrick, S. L. Alexander, "Phytoestrogens in Soy-Based Infant Foods: Concentrations, Daily Intake, and Possible Biological Effects," Proceedings of the Society of Experimental and Biological Medicine 217 (1998): 247-253.

[8.] L. W. Freni-Titulaer, J. F. Cordero, L. Haddock, G. Lebron, R. Martinez, and J. L. Mills, "Premature Thelarche in Puerto Rico: A Search for Environmental Factors, American Journal of Disabled Children 140 (1986):1263-1267.

[9.] R. Dabeka and A. McKenzie, "Lead and Cadmium Levels in Commercial Infant Foods and Dietary Intake by Infants 0-1 Year Old," Food Additives and Contaminants 5 (1988): 333-342.

[10.] US Department of Health and Human Services, "Methemoglobinemia in an Infant: Wisconsin, 1992," MMWR Morbidity and Mortality Weekly Report 42 (1993): 217-219.

[11.] L. B. Dusdieker, J. P. Getchell, T. M. Liarakos, W. J. Hausler, and C. I. Dungy, "Nitrate in Baby Foods," Archives of Pediatric and Adolescent Medicine 148 (1994): 490-494.

[12.] Environmental Working Group. Pouring It On: Health Effects of Nitrate Exposure, February 1996, www.ewg.org.

[13.] "Into the Mouths of Babes: Bottle-Fed Infants at Risk from Atrazine in Tap Water," July 1999. Environmental Working Group, 1718 Connecticut Avenue, NW, Suite 600, Washington, DC 20009.

For more information about toxins in formulas, see the following articles in past issues of Mothering: "Putting Babies Before Business," no. 88 and "The Nestle Boycott," no. 77.

Marsha Walker, RN, IBCLC, has been helping breastfeeding families since 1976. She serves as president of Lactation Associates, a private practice that educates and consults to healthcare professionals. Marsha is the executive director of the National Alliance for Breastfeeding Advocacy: Research, Education, and Legal Branch and also the author of several publications on breastfeeding.