Posted: Thursday, June 1, 2023
Long-term waterborne ingested nitrates are under study as a potential risk factor for prostate cancer, particularly aggressive tumors. Additionally, Cristina M. Villanueva, PhD, of the Institut de Salut Global de Barcelona, and colleagues observed that residential tap water levels of certain trihalomethanes (THMs)—the byproduct of the water treatment process—may be positively associated with prostate cancer. However, high intakes of fiber, fruit and vegetables, and vitamin C may reduce the negative effects of nitrates in terms of carcinogenesis. These findings were published in Environmental Health Perspectives.
“Being exposed to nitrates through drinking water does not mean that you are going to develop prostate cancer,” commented coauthor Carolina Donat-Vargas, MD, in an institutional press release. “Our hope is that this study, and others, will encourage a review of the levels of nitrate that are allowed in water, in order to ensure there is no risk to human health.”
The study recruited hospital-based incident prostate cancer cases and population-based controls in Spain between 2008 and 2013. The average nitrate and THMs levels in drinking water were linked with lifetime water consumption to calculate waterborne ingestion.
A total of 697 hospital-based incident prostate cancer cases (97 aggressive tumors) and 927 population-based controls were included in the study. The mean adult lifetime waterborne-ingested nitrate levels were 11.5 mg/day, the brominated (Br)-THMs levels were 20.7 mg/day, and the chloroform levels were 15.1 mg/ day in controls. A daily intake of < 11 g of fiber and high nitrate intake increased the likelihood of prostate cancer by a factor of 2.3. However, a daily intake of > 11 g of fiber and high nitrate intake was not associated with an increased likelihood of prostate cancer. Additionally, residential tap water levels of Br-THMs and chloroform showed inverse and positive associations with prostate cancer. This finding suggests inhalation and dermal routes could be relevant to the risk of developing prostate cancer.
Disclosure: For full disclosures of the study authors, visit ehp.niehs.nih.gov.