Selenium: Benefits for Health, Food Sources, and Possible Hazards
In the realm of nutrition, selenium, a trace mineral, has been gaining attention for its potential role in maintaining a healthy body. Recent clinical research suggests that selenium may play a complex role across several health conditions, including cardiovascular disease, cognitive decline, thyroid disorders, and cancer.
Starting with heart health, a study published in 2025 found that a higher dietary selenium intake is associated with a reduced risk of cardiovascular disease. This suggests that selenium obtained through diet (from foods like cereals, nuts, shellfish, red meat, and dairy) may support heart health by enhancing the activity of selenoproteins important for cellular function. However, the relationship may be nonlinear and complex, and not all studies agree.
In terms of cognitive decline, blood selenium levels tend to decline with age, leading to investigations into whether selenium deficiency contributes to cognitive impairment. While some research suggests a correlation between lower selenium levels and poorer mental function in older adults, evidence is mixed. More research is needed to clarify whether selenium supplementation could prevent or improve cognitive decline.
Selenium's importance in thyroid health is recognized, but current clinical research updates do not provide new data on this topic. It is well-established that selenium is critical for thyroid function because selenoproteins are involved in thyroid hormone metabolism and antioxidant defense in the thyroid gland. Selenium deficiency is linked to thyroid dysfunction and autoimmune thyroiditis.
Studies indicate that people with lower selenium intake may have an increased risk of various cancers. However, the effect of selenium supplements on cancer prevention remains unclear. More research is needed to understand if selenium from diet or supplements can effectively reduce cancer risk.
In clinical practice, maintaining adequate selenium status through a balanced diet is advisable, but routine selenium supplementation for preventing cardiovascular disease, cognitive decline, thyroid disorders, or cancer is not currently supported by definitive evidence. Sources of selenium include nuts, eggs, some fish, Brazil nuts, seafood, and meats.
It's important to note that the amount of selenium in food depends on the concentration of the soil and water where it grew. For instance, one cup of cooked brown rice contains 19 mcg of selenium, while three ounces of yellowfin tuna contain 167% of the Daily Value (DV) for selenium. Brazil nuts, known for their high selenium content, provide 989% of the recommended DV for selenium, with one ounce containing 544 micrograms (mcg).
While selenium supplements can offer health benefits, it's crucial to be aware of potential risks. An overdose of selenium supplements can lead to various health issues, including garlic-like breath, metallic taste, brittle nails, mottled teeth, gastrointestinal problems, neurological anomalies, fatigue, irritability, skin lesions, rashes, hair loss, kidney failure, heart failure, and even death. The upper limit for the optimal level of selenium in the body is 400 mcg.
In conclusion, selenium intake through diet is generally linked to reduced risk of cardiovascular disease and possibly certain cancers. Its role in cognitive decline is under investigation but not yet conclusive. Selenium’s importance in thyroid health is recognized but not detailed in current clinical research updates. The benefits of selenium supplementation, especially beyond correcting deficiency, remain uncertain, warranting further clinical studies.
- The predictive role of selenium, a trace mineral, extending to multiple health conditions, including heart health, cognitive decline, thyroid disorders, and cancer, is currently under investigation in the system of nutrition.
- In the realm of food and food benefits, it's discovered that a higher dietary intake of selenium is associated with a reduced risk of cardiovascular disease, thanks to the activity of selenoproteins essential for cellular function.
- As for other nutrition aspects, the scientific community is investigating whether selenium deficiency could contribute to cognitive impairment, but the evidence is mixed, and more research is needed to confirm this.
- In the health-and-wellness sector, selenium's critical role in thyroid function is recognized, as selenoproteins are key to thyroid hormone metabolism and antioxidant defense.
- When it comes to cancer prevention, some studies indicate that people with lower selenium intake may have an increased risk, but the effectiveness of selenium supplements in cancer prevention remains uncertain.
- In the context of immune system support, maintaining adequate selenium status through a balanced diet is advisable, but routine selenium supplementation for preventing avoidable health conditions is not currently supported by conclusive evidence. Sources of selenium include various foods, such as nuts, eggs, fish, Brazil nuts, seafood, and meats, but the quantity depends on the soil and water where they grew, making awareness of the food's selenium content important.
