由 home-healthhaven 
Experts believe that selenium, a mineral found in plant foods and animal meats from selenium-rich areas, may lower the risk of bladder cancer, especially for women. It’s also abundant in Brazil nuts. People with low levels of selenium in their blood are more likely to develop bladder cancer—the lower the level, the higher the risk.
In a study summarizing data from seven previous studies, researchers analyzed selenium levels from blood samples and toenail clippings of participants from both the United States and Europe (Belgium, Netherlands, and Finland). They found that individuals with the highest blood levels of selenium had a 39% lower risk of bladder cancer. This protective effect was more pronounced in women, possibly due to differences in how men and women metabolize the mineral.
However, further research is needed before recommending increased selenium intake. Scientists are working to establish the right dosage and identify which groups might benefit most from supplementation. Currently, the recommended daily allowance of selenium is 55 micrograms, and it’s generally considered that most American diets provide enough selenium. It’s advised not to exceed 400 micrograms per day.
In the U.S., selenium is commonly obtained from meats and breads. Deficiency is rare in the U.S., but can occur in other countries like New Zealand and China, where the soil contains less selenium. If you’re concerned about your selenium levels, consult a doctor before taking any supplements, as too much selenium can have harmful side effects.
Our bodies use selenium to produce selenoproteins, which act as antioxidants to prevent cellular damage. Some studies suggest that selenium may protect against certain cancers, but results from clinical trials on selenium supplements have been mixed. The selenium content in foods depends largely on the mineral content of the soil where they are grown or where animals graze. Notably, soils in northern Nebraska and the Dakotas have high selenium levels, so people living there often have higher blood selenium levels.
As we await more research on selenium’s role in preventing bladder cancer, it’s important to remember that maintaining a balanced diet and healthy lifestyle can reduce your risk of many diseases and support overall health.