Numerous studies, including a national survey by the Centers for Disease Control (CDC), have found that black children suffer significantly higher rates of dental fluorosis than white children. (Martinez-Mier 2010; Beltran-Aguilar 2005; Kumar 2000, 1999; Williams 1990; Butler 1985; Russell 1962). Not only do black children suffer higher rates of fluorosis, they suffer the most severe forms of the condition which are marked by dark brown staining and deterioration of the enamel. While the reasons for this increased rate of fluorosis have yet to be definitively determined, there are several risk factors for fluoride toxicity that are present at elevated rates in the black community. These risk factors include:

1. Reduced nutrient intake;
2. Higher levels of lead exposure;
3. Higher prevalence of health conditions (e.g., kidney disease and diabetes) that render the body more vulnerable to fluoride intake; and
4. Higher intakes of fluoride.

A) Reduced Nutrient Intake

Voluminous research spanning back to the 1930s shows that populations with nutrient deficiencies are harmed by fluoride exposures otherwise safe for the general population. A 1952 study in the Journal of the American Dental Association warned:

“The data from this and other investigations suggest that malnourished infants and children, especially if deficient in calcium intake, may suffer from the effects of water containing fluorine while healthy children would remain unaffected…Thus low levels of fluoride ingestion which are generally considered to be safe for the general population may not be safe for malnourished infants and children. Therefore, the nutritional status must be carefully assessed and guarded in areas with endemic fluorosis. Nutritional studies should be included in any comprehensive program of fluoridation of water with special attention to chronically ailing infants and children…When an individual or a population group shows mottling beyond the degree expected, the health and nutritional status of that group should be investigated.” (Massler & Schour 1952).

Research has repeatedly shown that black Americans have lower nutrient intakes than caucasians. (Fulgoni 2007, Goolsby 2006; Sharma 2004). As summarized in a recent review:

“As a group, African-Americans consume a diet that is lower in recommended nutrients and meet fewer of the national recommendations than the average American. In comparison to national recommendations, the African-American diet is more likely to be low in vitamins and minerals, including calcium, and higher in fat. Additionally, the food pattern in the African-American diet includes more meat and fats, while being lower in fruits, vegetables and dairy foods.” (Byers 2005).

One reason for the lower nutrient intake in the black community is the higher prevalence of lactose intolerance that is known to exist. (Byers 2005). Due to this high rate of lactose tolerance, black children consume significantly less milk than white children. Since milk is an important source of calcium, and since calcium is important for reducing fluoride’s toxic effects on mineralized tissues (bones and teeth), lower milk consumption could be an important reason for the increased fluorosis rate in the black community. Indeed, recent research has specifically found that milk consumption is associated with reduced severity of fluorosis in areas with high levels of fluoride in water. (Rango 2012).

Another reason for the reduced nutrient intake in the black community is the scarcity of fresh grocery stores in low-income urban areas. Recent studies have found that the lack of grocery stores in low-income black neighborhoods severely limits access to fresh fruits and vegetables (a major source of anti-oxidants). (Kolker 2008; Burt 2006; Tellez 2006). Consistent with this, the level of anti-oxidants in the blood of otherwise healthy black adults has been found to be significantly lower than the anti-oxidant levels in white adults. (Watters 2007). This is important because research has repeatedly shown that fluoride increases the level of oxidative stress in the body and, as a result, anti-oxidants play a critical role in defending the body from fluoride toxicity. (Barbier 2010).

B) Lead Exposure

Research has found that the black community has higher levels of lead intake than the white community. (Bernard 2003; Lanphear 1996; Brody 1994). This has been demonstrated through studies of lead levels in both blood and bone. (Jones 2009; Theppeang 2008). This is significant because, according to recent animal research, heightened exposure to lead can exacerbate the toxicity of fluoride exposures. (Leite 2011; Niu 2009). In one animal study, rats with both fluoride and lead exposure had more severe forms of fluorosis than rats with fluoride exposure alone. (Leite 2011). Thus, the higher lead exposure in the black community may help to explain the greater severity of dental fluorosis found in the black community.

C) Fluoride Intake

Some studies have found that black children consume more fluoride from water and beverages than white children. (Sohn 2001). This may be the result of increased lactose intolerance which leads to the substitution of milk with water and other processed beverages. In addition, studies have found that black children are less likely to be breast-fed than other racial groups. (Robinson 2009). A recent national survey by the CDC, for example, found that “non-Hispanic blacks had a lower prevalence of breastfeeding initiation than non-Hispanic whites in all but two states.” (CDC 2010). This is significant because infants consuming formula made with fluoridated water can ingest up to 200 times more fluoride than a breast fed infant, and have been found to be at greater risk of developing dental fluorosis in their permanent teeth. (Hong 2006).

D) Health Conditions

Fluoride’s toxicity is significantly exacerbated by health conditions, including kidney disease and diabetes, that are significantly more prevalent among communities of color. Black Americans, for example, are  over two times as likely to develop chronic kidney disease and nearly four times as likely to experience kidney failure as caucasians. (Muntner 2012; US Renal Data System, 2005). to develop kidney failure than caucasians, and nearly twice as likely to suffer from diabetes than are whites. (Katzmarzyk 2012).

References:

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Beltran-Aguilar ED et al. (2005). Surveillance for dental caries, dental sealants, tooth retention, edentulism, and enamel fluorosis — United States, 1988–1994 and 1999—2002. MMWR Surveillance Summaries 54(3): 1-44.

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