From the journal of human lacation.

Declining breastfeeding rates and the aggressive marketing of breastmilk substitutes has blurred the distinction between breastmilk and formula. Claims that infant formula is safe, economical, easy to use, and nutritionally complete are challenged in this article, the intent of which is to ralse he awareness of health workers to the non-publicized side of infant formula. Non-proprietary, referenced data is provided to illustrate that formula and breastmilk are not the same thing, and that health outcomes of infants who consume each may be different. Guilt is often cited by health workers as a reason to avoid informing parents about the risks of artificial feeding. Suggestions are offered for addressing this reasoning. KEYWORDS : breastfeeding, breastmilk, hazards, infant formula. JHL 9:97-107,1993

INTRODUCTION

Religious, cultural, and scientific beliefs throughout history have influenced what and how infants are fed. Forms of artificial feeding have existed since antiquity, including milk from other species, pap, gruel, panada, and broth. Rapid development in science, technology, and broth. Rapid developments in science, technology, and medicine, and changes in social and economic trendy in the late 1800s, gave birth to a new type of baby food, commercial infant formula.1 By the eiid of the 1800s, proprietary infant foods were being sold in at least 17 countries. Early formulations were developed by physicians and industry and promoted to both parents and health professionals; currently they are promoted through multimedia public advertising campaigns. The categories discussed are not inclusive of all known or potential, hazards of the use of infant formula. References were chosen for their clarity of sample groups and distinction between health outcomes of breastfed. formula-fed, and mixed-fed infants.

INCREASED MORBIDITY AND MORTALITY

The widespread belief that breastmilk confers health benefits only in developing countries is contradicted by the overwhelming data published in the last ten years. Clinicians in developed countries often inform parents that formula is equivalent to breastmilk, reassuring them that health outcomes are the same. Yet in 1981, Allen Cunningham published Hospitalization patterns of a homogeneous, middle class, white, 1,18 population and concluded that, “I would expect 77 hospital admission for illness during the first four months of life in every 1000 bottle-fed infants. The comparable figure for breastfed infants is five hospital admissions”

Formula-fed babies develop acute diseases at higher rates.

Formula feeding is consistently associated with immune system disorders. Breastfeeding enhances serum as well as secretory responses to commonly used vaccines; high antibody levels to diphtheria and polio are seen up to one to two years after vaccination in breastfed babies. This is thought to occur because breastmilk primes the infant to produce antibodies. Formula has no such effect.16

A risk/benefit analysis by the United States National Institute of Environmental Health Sciences estimated that for every 1000 infants born in the US each year, four will die because they are not breastfed.17 Most of the infant deaths worldwide (1.5 million/year) related to artificial feeding are due to diarrheal illness.

In the United States, five hundred children aged one month to four years die each year from diarrhea.18 At least 70 percent of these deaths are caused by rotavirus infection in children four to 36 months of age, against which breastmllk has a known protective effect.” One sudden infant death per 1000 live births occurs as a result of failure to breastfeed in western industrialized nations.19.11

Formula feeding has been identified as a risk factor for sudden infant death syndrome (SIDS, cot death) in the results of the SIDS study conducted by the National Institute of Child Health and Human Development.21 Seventy-nine percent of deaths from SIDS in New Zealand are attributable to three factors-maternal smoking, prone infant sleeping position, and not being breastfed.22

A multicenter study in British neonatal units showed breastfeeding to be the single most effective method of preventing necrotizing enterocolitis (NEC) in preterm infants. Infants born at more than 30 weeks gestation whose diet contained any breastmilk rarely experienced NEC. It was 20 times more common in those babies fed only formula. The authors estimated that exclusive formula feeding could account for 500 extra cases of NEC each year, and the death of 100 (20 percent) of these infants.23

Formula-fed preterm infants are at higher risk for respiratory failure, bronchopulmonary dysplasia and retinopathy of prematurity if their diet is not supplemented with inositol during the first week of life.24 Inositol, a component of membrane phospholipids, significantly reduces the severity of respiratory distress syndrome (RDS) by enhancing the synthesis and secretion of surfactant in immature lung tissue.25

Inositol concentrations in human milk are several times higher than in formula, and even more is found in preterm colostrum. Many formulas lack inositol altogether. Preterm infants fed inositol-rich breastmilk increase their serum inositol levels; premies receiving formula show no concomitant rise in serum inositol levels.26

The increased morbidity and mortality of formula-fed infants is reflected in the greater expenses for health care of these children. When an accounting is done of the health care dollars spent on additional hospitalizations, out-patient care, and emergency room service, the total is in the hundreds of millions of dollars. In 1981, this number was estimated at $300 million.27

INFANT FORMULA IS ASSOCIATED WITH LEARNING DEFICIENCIES

Infant formulas provide nutrients whose goal is to support growth in human infants. They are not tailored like breastmilk to enhance the growth and development of the brain and central nervous system-the distinguishing organ and system of humans. Lower intellectual performance of formula-fed infants has been documented by Morrow-Tlucak et al. They fround that scores on the Bayley Mental Development Index were lower in formula-fed children at one to two years of age Scores were directly correlated with duration of breastfeeding.27

Bauer et al. showed that scores on the McCarthy Scales of Childrens’ Abilities were significantly lower at three years of age for children breastfed the least.28 Lower performances of formula-fed children were seen on developmental tests by Taylor and Wadsworth in five-year-old children.29

Formula-fed preterm infants scored significantly lower in the Bayley Mental Development Index when Morley et al. studied the developmental status of 771 premies at 18 months of age.30 Formula-fed premature infants had lower IQ scores at age seven to eight years than breastmilk-fed premature infants even after adjustment for the mother’s education and social class.31

CARDIORESPIRATORY DISTURBANCES DURING BOTTLE-FEEDING

Signficant alterations in breathing patterns have been observed during bottle-feeding of both term and preterm infants. Rapid milk flow from artifical nipples results in repeated swallowing and airway closure which decreases the time available for breathing. In preterm infants, decreases in TcO2 tension and 02 saturation during bottle-feeding are seen frequently and are often accompanied by apnea (absent airflow for >20 seconds), bradycardia (heart rate <100 beats per minute) and cyanosis (blue coloring).32,33

The high frequency of cardiorespiratory disturbances during bottlefeedine indicates that many premies lack the respiratory control and a ability to self-regulate a rapid milk flow. Soft pliable premie nipples have a high flow rate which may reduce feeding time, but which can compromise the infant’s breathing and increase the cardio-respiratory load.34

Both preterm and term infants experience occasional episodes of prolonged airway closure (up to 30 seconds) after swallows; obstructed breaths during bottle-feeding further at the time available for effective breathing.35

Term neonates also experience decreases in 02 saturation below 90 percent during bottle-feeding. Decreasing the milk flow per suck may minimize the feeding-related 02 desaturation by increasing the time available for breathing by spacing swallows. Apnea and bradycardia occur during bottle-feeding more frequently than is recognized in healthy fullterm infants. In one study of 50 healthy term babies, nine developed bradycardia during bottle-feeding, apnea preceded the bradycardia in six of these babies, and hypopnea (marked reduction in ventilation) occurred in three. One of the nine experienced central apnea (no respiratory efforts) and two developedcyanosis.36

Increased apnea and obstucted breathing in the First days of life during bottle-feeding was seen in some infants who subsequently experienced SIDS. Mathew suggests that aberrant respiratory patterms appearing only during bottle-feeding may have potential for identifying future SIDS infants. It is unknown if this respiratory defect persists in SIDS babies but disappears in normal babies.37

ALLEPGIC MANIFESTATIONS OCCUR AT GREATEIR PATES AND ARE MORE SEVERE IN FORMULA-FED INFANTS

Cow’s milk is the most common allergen during infancy and childhood. Up to 7.5 percent of formula-fed infants demonstrate allergy to cow’s milk-based formulas.38 Up to 50 percent of children sensitive to cow’s milk show soy hvpersensitivity also.39

Allergic reactions include hives, wheezing, vomiting diarrhea, eczema, malabsorption, and failure to thrive. Merrett et al. studied 500 babies born to allergic families ind concluded that any breastfeeding even for a short time was associated with much lower incidence of wheezing, prolonged colds, diarrhea, and vomiting.40 et al. documented that by three to four months of age, formula-fed or formula-supplemented infants had marked rises in IgE and IgG antibodies to cow’s milk protein; exclusively breastfed infants shored no such rise. Sixty-two percent of the formula-exposed infants showed allergic symptoms of chronic nasal congestion and diarrhea, contrasted with 13 percent of the breastfed babies.41

Host et al. reports that 2,5 percent (39/1539) of infants exposed to cow’s milk formula in the newborn nursery developed cow’s milk- allergy, compared to none (0/210) of the infants who avoided exposure. Nine infants had symptoms of cow’s milk allergy while exclusively breasted when their mothers drank cow’s milk. All nine had been given formula in the nursery, although only one of the nine mothers knew this. The authors suggest that the early exposure to cow’s milk protein in the hospital may have been the source of sensitization.42

In an attempt to reduce their allergenicity, some formulas have been modified by using hydrolysed casein and hydrolysed whey bovine (cow) protein sources. These formulas are generally referred to as “hypoallergenic.” Soy formulas remain antigenic and have provoked adverse reactions in some cow’s-milk-allergic infants; the American Academy of Pediatries (AAP) recommends against their use for the management of infants with documented cow’s- milk-protein allergy.43

Casein hydrolysate and more recently whey hydrolysate formulas are frequently recommended for IgE-mediatd cow’s-milk-allergic infants, but the AA.P states, ‘No published, well controlled, double-blind studies exist to support the support the use of either casein or whey hydrolysates for prophylaxis or treatment of infants with milk hypersensitivity.44 Anaphylactic reactions (life-threateningshock) to casein hydrolysate formulas [Nutramigen,45 Alimentum 46 and Pregestimil47] and to whey hydrolysate formulas [Carnation Good Start 48 and Alfare (Nestle)49] have been reported.

The AAP states that a whey hydrolysate formula may be an acceptable alternative to cow’s milk-based or soy formulas for infants who are intolerant, but not allergic, to cow’s milk.44 “Hypoallergenic”, does not mean “non-allergenic”. Continuing to use the term “hypoallergenic” may be misleading, given the reported life-threatening reactions that have occurred in infants fed these formulas. Consumers, parents, and health care providers can be confused by this term and may not have identified the highly sensitized child.

Protein fractions still exist in all of these formulas (particularly Good Start) that are capable of causing reactions in sensitive infants. Sampson et al. recommend that, “In milk-allergic children who had a severe life-threatening reaction after the ingestion of milk, it may be prudent to administer the first dose of Alimentum in a physician’s office, where resuscitation can be initiated in the event that allergic symptoms develop”. 50

By definition, a “hypoallergenic” formula is one tolerated without symptoms by 90 percent of subjects allergic to cow’s milk. This places the other 10 percent at risk of consuming a food whose safety for them is questionable. United States federal proceedings required the Carnation Company (a subsidiary of Nestle SA) to drop advertising claims that the formula would not cause allergic reactions, to stop describing the product as hypoallergenic, and to cease citing scientific evidence for its health claims. A new amino-acid-derived infant formula, Neocate (Scientific Hospital Supplies, Gaithersburg, Maryland) is undergoing clinical trials in the US and UK to determine its safety for use in cow-milk-allergic infants.

CONTAMINANTS IN INFANT FORMULA

Formula-fed infants are at higher risk for ingestion of lead, aluminum, and other heavy metals as well as iodine. The amount of lead in formula has continued to drop over the last decade and lead-soldered cans have been phased out of use. Low levels of lead exposure can negatively affect cognitive development of infants and young children, even at levels as low as 5-10 ug/dL. Lead intoxication in infants is more common than previously believed. This is frequently due to the practice of boiling the water used to reconstitute powdered or concentrated formula. Label Constructions advise to boil water for five minutes before mixing formula. However, this action concentrates any lead in the water, thus exposing infants to substantial amounts of lead with each feeding, depending on the amount of lead in the water and how long it was boiled. Use of no- or low-iron formula also increases lead absorption. To minimize lead levels in formula, water should not be boiled unless it is bacteriologically unsafe, lead levels should be checked in the municipal drinking water, plumbing should be checked in dwellings and replaced if it contains lead or lead solder in the joints. First draw water should not be used. Parents can run the water about 15 minutes to decrease lead levels in the first morning run of water. Researchers suggest that lead screening begin at the age of six months for children with any frequent contaminant of powdered formulas available likelihood of lead exposure, including babies fed powdered or concentrated formula.73

Aluminum levels in formula can be up to 60 times higher than in breastmilk. Infants with renal problems are more likely to deposit large amounts of aluminum in brain and bone tissue. Two infants with renal problems died of aluminum intoxication; powdered formula was the source .74 Potential sources of aluminum contamination in formula include the raw materials, especially soybeans, contaminated additives such as calcium and phosphorous salts, the manufacturing process itself, and storage containers. Human milk contains <5-45 ug/L of aluminum while one soy formula measured 684-2346 ug/L.75 Calcium and phosphorous metabolism can be disturbed by aluminum contamination in nutrients. The use of soy formula in term infants has been reported to decrease bone mineral content76 and to be associated with smaller carpal bones on x-ray at three months.77 Preterm infants can experience bone demineralization and rickets when fed soy formula. The increased amounts of calcium and phosphorous added to these formulas to lower serum aluminum concentration” could place infants at risk for hypocalcemic tetany, as previously discussed on pages 100-1.

Formula-fed infants can be exposed to levels of iodine close to ten times that found in breastmilk. Iodine enters formula in milk from cows who eat feed high in iodine and from the iodine used by the dairy industry in teat washes and sanitizing solutions for milking equipment. Hypothyroldism can result from high levels of iodine. Some researchers feel the iodine level is too high in formula, especially since little data exists on iodine levels in formula-fed infants and the effects it may have on neonatal thyroid function.

In 1983, Michigan infant formula was found to be contaminated with halogenated hydrocarbon solvents such as trichloroethylene and perchloroethylene from well water used in the making of formula. The wells had been sampled for contaminants; they were not checked for halogenated hydrocarbon solvents, which are the most common groundwater contaminants.

Bacterial contamination of formulas continues to be of concern as more incidents occur and clinical illness results from tainted products. During November-December 1985, an outbreak of Salmonella eating occurred in the United Kingdom, which resulted in the death of one infant and admission to hospital of 15 percent of the other affected infants. The source was powdered formula contaminated at the factory. Raw milk or improperly pasteurized milk can introduce bacteria to the drying process used to manufacture powdered formula.79 Enterobacter sakazakii has been found as a frequent contaminant of powdered formulas available in thirteen countries including the US.80 It has been identified as the cause of sepsis and meningitis in neonates who received formula containing this type of bacteria.81,82

In June 1990, 63,760 gallons of a liquid soy concentrated formula was placed under a Class I recall by the US Food and Drug Administration (FDA). Class I means the product can be life threatening. FDA inspectors noticed swollen cans of formula, some of which were ready to burst. One of the lots could have been life-threatening to infants. The company did not determine the source of the contamination and a month later found that cans from an entire production run had started to swell. The plant was shut down by the company.83 The FDA has published guidelines for bacterial testing of powdered formulas, listing both the microorganism and the amount that would result in an adulterated product.

SUMMARY

Some health workers reassure parents that babies do just as well on either type of food and that in developed countries there is no difference in health outcomes between the two feeding methods. Others have little knowledge of lactation management and are not comfortable spending time with breastfeeding mothers.

Evidence continues to grow that the health outcome and cognitive abilities of formula-fed and breastfed infants may be different. Formula-fed infants may not be developing their health and cognitive abilities as their natural potential would have permitted. The trend away from breastfeeding is particularly worrisome in light of these data. Given the explosion of new research on breastmilk and breastfeeding, perhaps health workers should take more than a neutral stance on infant feeding methods.

Health workers can contribute to more complete parental in-formed decision-making by initiating infant feeding discussions at appropriate prenatal times. These include routine prenatal visits, childbirth classes, early pregnancy classes, breastfeeding classes, etc. I emphasize the following information in prenatal breastfeeding classes:

formula and breastmilk are not the same thing;

health outcomes from their use are different;

breastmilk is species specific, designed to promote brain growth and protect against both acute and chronic diseases, formula has no such effect.

breastmilk promotes development of the infant’s genetic potential

there is a difference between being OK and developing optimal health and cognitive potential

all formulas are not the same. Standard ones are based on cow’s milk (many parents are unaware of this). Seven to eight percent of babies are allergic to cow’s milk formula; 50 percent of these babies also are allergic to soy formulas. Use of cow’s milk is not recommended until after the baby is one year old;

formula is expensive to use; it costs approx £500 for one year’s supply;

lead levels in drinking water should he checked if powdered or concentrated formula requiring the addition of water is used. Do not boil water; mix the formula as directed, and clean bottles and nipples carefully.

Formula feeding is time consuming.

Parents are entitled to the truth. Parenting decisions are not always easy or straight forward. Omitting information does not contribute to a trusting relationship between parent and provider. The decision to inform parents of these facts may provoke displeasure and animosity from co-workers and colleagues, for this is not a popular approach in some settings. However, all health workers involved with childbearing families need to consider their responsibilities regarding the issue of informed decision-making.