Friday July 3, 2015 (foodconsumer.org) -- An animal study recently published in PLos One suggests that high intake of fluoride may damage the female reproductive system.  Fluoridation is common in western countries although the safety and efficacy of fluoridation remains controversial.

The study led by Songna Yin from Northwest A&F University, in Yangling,  Shaanxi, China and colleagues examined the reproductive toxicity of fluoride at high concentrations in female mice.  For the study, female mice were fed a fluoride solution for five weeks and they suffered damage to the histological architecture of ovaries.

The study specifically found exposure to high concentrations of fluoride reduced the expression of certain genes including Dazl, Stra8, Nobox, Sohlh1, and ZP3 genes which are associated with oocyte formation.  

Genes such as Bmp15, Gdf9, H1oo, and ZP2 that are involved in oocyte growth and the induction of the acrosome reaction were also suppressed when the female mice were fed a fluoride containing solution.

Additionally, fluoride exposure reduced DNA methylation and histone acetylation, which are important for germline development and genomic imprinting in mammals.

As a result, fluoride exposure lowered the number of in vitro fertilization of mature oocytes and decreased the fertility of the female mice.

The study concluded that high exposure to fluoride can significantly reduce the number of mature oocytes and hamper their development and fertilization in female mice.

The study provides another possible risk factor for female infertility or reproductive disorders.

It has been reported that fluoride can lower IQ of children and may boost the risk of bone cancer in boys. High fluoride exposure can also cause dental fluorosis while it remains uncertain whether fluoride can help prevent dental cavity.  

Some food consumers would like to get rid of fluoride in the fluoridated drinking water.  It should be noted that only filters with reverse osmosis membranes can remove fluoride. (David Liu)

Yin S, Song C, Wu H, Chen X, Zhang Y (2015) Adverse Effects of High Concentrations of Fluoride on Characteristics of the Ovary and Mature Oocyte of Mouse. PLoS ONE 10(6): e0129594. doi:10.1371/journal.pone.0129594