Safety l Fluoridation Facts 67 45. Is the consumption of water fluoridated at recommended levels harmful to kidneys? Answer. Consuming water fluoridated at recommended levels has not been shown to cause or worsen kidney disease. Fact. Approximately 60% of the fluoride absorbed daily by adults (45% for children) is removed from the body by the kidneys.52 Because the kidneys are constantly exposed to various fluoride concentrations, any health effects caused by fluoride would likely manifest themselves in kidney cells. However, several large community-based studies of people with long-term exposure to drinking water with fluoride concentrations up to 8 ppm have failed to show an increase in kidney disease.5,136,169 In a report issued in 1993 by the National Research Council (NRC), the Subcommittee on Health Effects of Ingested Fluoride stated that the threshold dose of fluoride in drinking water which causes kidney effects in animals is approximately 50 ppm — more than 12 times the maximum level allowed in drinking water by the Environmental Protection Agency. Therefore, they concluded that “ingestion of fluoride at currently recommended concentrations is not likely to produce kidney toxicity in humans.”8 Furthermore, the NRC report on fluoride in drinking water issued in 2006 concluded that there were no published studies that demonstrate that drinking water fluoridated at recommended levels can damage kidneys. The report further concluded that fluoride concentrations need to be higher than 4 ppm to affect kidney tissues and function.9 A review of scientific studies completed in 2007 for Kidney Health Australia (KHA),170 summarized findings from the recent literature related to the health effects of fluoridated water for people with chronic kidney disease (CKD). The purpose of the review was to provide an up to date summary of studies on the topic so that KHA, the leading organization in Australia that promotes kidney and urinary tract health, could develop a fluoride position paper. The review concluded that while studies on the topic are limited, “there is no evidence that consumption of optimally fluoridated drinking water increases the risk of developing CKD.” For those people who have CKD, the report stated that “there is no evidence that consumption of optimally fluoridated drinking water poses any health risks for people with CKD, although only limited studies addressing this issue are available.” There is limited evidence that people with advanced CKD (stages 4 or 5) “who ingest substances with a high concentration of fluoride may be at risk of fluorosis.” Accordingly, the report recommended that it would be “prudent” for patients with advanced CKD to monitor fluoride intake and avoid fluoride-rich substances. These conclusions are the basis for KHA’s position statement on fluoride which was released in 2007.170 The position statement was updated in 2011 and concluded that “there has been no new published evidence to contradict the 2007 KHA Position Statement.”171 According to information on their website, the National Kidney Foundation is the leading organization in the U.S. dedicated to the awareness, prevention and treatment of kidney disease. A paper titled Fluoride Intake in Chronic Kidney Disease dated April 15, 2008,172 developed by the National Kidney Foundation (NKF) and posted on the NKF website includes the following points under the header “Analysis and Recommendations”: • Dietary advice for patients with CKD should primarily focus on established recommendations for sodium, potassium, calcium, phosphorus, energy/calorie, protein, fat, and carbohydrate intake. Fluoride intake is a secondary concern. • Individuals with CKD should be notified of the potential risk of fluoride exposure by providing information on the NKF website including a link to the Report in Brief of the National Research Council and the Kidney Health Australia position paper. The risk is likely greatest in areas with naturally high water fluoride levels. • The NKF has no position on the optimal fluoridation of water. The oral health of people with CKD is certainly of interest to the NKF, but balancing the overall benefits and risks of fluoride exposure is the primary concern.172 Many people with kidney failure depend on hemodialysis (treatment with an artificial kidney machine) for their survival. During hemodialysis, the patient’s blood is exposed to large amounts of water each week (280-560 quarts). Therefore, procedures have been designed to ensure that the water utilized in the process contain a minimum of dissolved substances that could diffuse indiscriminately into