Kales and tomatoes, two of the most eaten vegetables in Kenya, are being blamed for the browning of teeth among residents of Nakuru County in Kenya’s Rift Valley.
A recent analysis of the two vegetables shows they contain fluoride levels much above what is safe for human consumption.
Margret Maina, Enos Wambu and John Lusweti of University of Eldoret, had analyzed the levels of fluoride in kales and tomatoes in all the seven sub-counties of Nakuru County
Fluoride in all the tested samples, the study says was above the World Health Organization and Food and Agriculture Organization standards.
“All were above recommended daily allowances which poses a health hazard to consumers,” said the study initially published in Africa Environmental Review Journal.
Naivasha sub-county, the report shows recorded the highest levels of fluoride in kales while the lowest concentration was recorded in Molo.
For tomatoes, the highest fluoride concentration was recorded in Gilgil and the lowest was found in Nakuru West.
Fluoride levels were highest in drier regions of the county compared to wetter regions such as Subukia and Rongai.
“However, in all cases the mean fluoride levels in tomatoes and kales exceeded dietary recommended daily allowance.”
The research concludes that tomatoes and kales from Naivasha, Gilgil, Rongai, Subukia, Nakuru West, Nakuru East and Molo are exposed to high levels of fluorides and pose a health risk to consumers.
This is attributed to the volcanic rocks in the region as Nakuru County lies along the Great Rift Valley.
The researchers recommend that the intake of these foods be reduced as much as possible. “We recommend that farmers grow crops with relatively low capacities to enrich fluoride, such as those with seeds or tubers as the main edible parts.”
Another recent study by the same university found 86 per cent of all the sampled cattle and sheep had dental fluorosis.
“There is evidence to indicate this is as a result of ingestion of fluoridated drinking water and feeds.”
The team had sampled 549 animals consisting of 242 cattle and 307 sheep in Gilgil, Njoro, Egerton, Naivasha, and Nakuru areas of Nakuru County.
This study established the presence of significant levels of fluoride concentration in water and feeds “On the whole, livestock relying on these feed sources are undoubtedly faced with fluoride toxicity.”
Nakuru County is known for high rates of dental fluorosis in both children and adults. In consecutive years young men and women from the region have found recruitment into the disciplined forces difficult because of stained teeth and suspected weak bones.
Dental fluorosis is a teeth defect causing white or brown spots on the tooth surface or enamel, which in most cases are so mild that only a dentist can detect.
This permanent staining develops in the first eight years of life from consuming too much fluoride. The teeth can then continue discolouring from lacy white spots to yellow and then to dark brown.
The mineral fluoride occurs naturally in soil, water and foods but consumption of too much may lead to dental or skeletal fluorosis, which can damage bones and joints.
Ground water in Nakuru areas has been known to contain high levels of fluoride many times above the allowable levels of 1.5 milligrammes per litre by the World Health Organisation.
By Gatonye Gathura