New Understandings

From the 1950s through to the 1990s, newborn infants were routinely prescribed fluoride drops (“supplements”) as a means of building stronger teeth. Although infants rarely have teeth in their mouth, dentists believed that ingesting fluoride during infancy had a “pre-eruptive” benefit. Under this paradigm, dentists believed that the ingested fluoride would be incorporated into the teeth prior to eruption and, like calcium for bone, make the fluoride-rich teeth stronger for life.

Over the past thirty years, several scientific discoveries have dramatically revised our understanding of fluoride’s benefits, and risks, for infants. Based on these discoveries, a consensus has emerged among even the most ardent pro-fluoride organizations, that infants under six months of age should receive no fluoride supplementation.

While dental organizations and government health agencies have been wary of addressing the problem with using fluoridated water in infant formula, many dental researchers now openly state that fluoridated water should not be used to reconstitute infant formula.

So, what are the new understandings that led to the change in recommendations? The following are five of the key discoveries.

Understanding 1: Fluoride Is Excluded from Breast Milk

The regime of fluoride supplementation for infants first began to unravel in 1981 when European dental researchers reported that human breast milk contains virtually no fluoride. Breast milk is designed to be the sole source of nutrition for a child, and is thus extremely rich in the nutrients that a baby needs for healthy development. Although dentists had long claimed that fluoride was an essential nutrient, the European researchers found that breast milk contained a mere 4 parts per billion of fluoride, about 250 times less fluoride than is added to water in fluoridation programs. In fact, the European team found evidence of a protective mechanism that specifically excluded fluoride from the mothers’ bloodstream from entering the milk. According to the researchers:

“The existence of a physiological plasma-milk barrier against fluoride suggests that the newborn is actively protected from this halogen. Hence the recommendation made in several countries to give breast-fed infants fluoride supplementation should be reconsidered.” (Ekstrand 1981).

Understanding 2: Fluoride Is NOT a Nutrient

After the discovery that fluoride is largely excluded from entering breast milk, the notion that babies “need” fluoride became a very tenuous one. It should not have been surprising, therefore, when the National Academy of Sciences concluded in 1989 that fluoride is not an essential nutrient. (NAS 1989) Despite decades of attempts to find some essential role of fluoride in human nutrition, the NAS concluded that no such role exists, and that humans do not need fluoride for any physiological function, including the formation of teeth.

Understanding 3: Ingested Fluoride Provides NO Pre-Eruptive Benefit to Teeth

The basis for supplementing an infant’s diet with fluoride began to further unravel in the late 1980s and early 1990s when dental researchers began openly reporting that fluoride does not work the way they once thought it did. As noted above, dentists once believed that ingesting fluoride provided a “pre-eruptive” benefit to a baby’s teeth. Thus, even if the baby’s teeth had not yet erupted, fluoride was still deemed beneficial to the future teeth.

In the 1980s, dental researchers discovered that this belief was mistaken. Rather than working pre-eruptively, the modern research clearly showed that fluoride’s benefit came after the teeth erupted and through topical, not systemic, application. In other words, dentists began admitting that swallowing fluoride before the teeth erupt is all but worthless. Although belatedly, the Centers for Disease Control finally accepted this new understanding in 1999.

The implications of this understanding are obvious: If a baby has no teeth in its mouth, there is no need to give it fluoride. And when a baby does have a tooth in its mouth, there is no need to actually swallow fluoride.

Understanding 4: Formula Made with Fluoridated Water Provides Unsafe Dose

In 1997, the Institute of Medicine set the safe limit (“upper tolerable intake”) of fluoride ingestion at 0.1 mg/kg/day. Subsequent research over the past 15 years has repeatedly demonstrated that infants who consume formula made with fluoridated water can easily exceed the limit deemed safe by the Institute of Medicine. In 2006, for example, an analysis by the Environmental Working Group, found in some urban areas of the United States up to “60 percent of the exclusively formula fed babies exceed the safe dose of fluoride on any given day.”

Two facts make this situation particularly striking. The first fact is that infants fed formula made with fluoridated water ingest the highest fluoride dose from water of all age groups in the population. The second fact is that babies who are breast-fed receive the lowest fluoride dose (by far) in the population. Thus, the addition of fluoridated water to formula turns the natural situation on its head: rather than being the population most protected from fluoride exposure, babies become the population least protected from fluoride exposure.

Understanding 5: Infant Consumption of Fluoridated Water Causes Dental Fluorosis

In light of the high doses babies receive from fluoridated formula, it should have again been no surprise to researchers to discover, as they did, that exposure to fluoridated water during infancy is a major risk factor for dental fluorosis. Beginning in the 1990s, a flurry of studies began reporting that children who consumed fluoridated formula when they were babies had higher rates of dental fluorosis on their permanent teeth.

Dental Fluorosis is a mineralization defect of tooth enamel that results in various degrees of discoloration, from white splotches and streaks to brown/black staining. Numerous studies have found that dental fluorosis can cause a child significant embarrassment about their physical appearance, particularly when the fluorosis is visible on the front teeth. It was particularly significant, therefore, when researchers reported in 2006 that the fluoride exposure during the first year of life is strongly linked to fluorosis on the front teeth.

References

Ekstrand J, et al. (1981). No evidence of transfer of fluoride from plasma to breast milk. British Medical Journal 283: 761-2.