Selenium deficiency is a condition where the body lacks adequate levels of selenium, an essential trace mineral critical for antioxidant defense, thyroid function, and immune health. It is caused by insufficient dietary intake of selenium, often related to living in geographic areas with selenium-poor soil, or conditions affecting selenium absorption. The Selenium blood test is the most important test for diagnosis because it directly measures serum selenium levels to identify deficiency.
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Selenium deficiency is caused by insufficient dietary intake of selenium, often related to living in geographic regions with selenium-poor soil that produces low-selenium crops and food sources. Your body cannot produce selenium on its own, so you must obtain it from food sources like Brazil nuts, seafood, meat, and whole grains. People living in certain parts of China, Russia, and New Zealand are at higher risk due to naturally low selenium content in local soil, and those with digestive disorders like Crohn disease or celiac disease may have impaired selenium absorption even with adequate dietary intake.
The Selenium blood test is the most important test for selenium deficiency because it directly measures selenium levels in your serum, providing an accurate assessment of your current selenium status. This test can identify low selenium levels before serious complications develop, such as Keshan disease (a form of heart failure) or Kashin-Beck disease (a type of osteoarthritis). For a more comprehensive evaluation, the Selenium 24-Hour Urine test can be added to measure selenium excretion and assess how your body metabolizes and stores selenium over time, giving your healthcare provider a complete picture of your selenium status.
You should get tested if you live in or have recently moved from areas known for selenium-poor soil, experience unexplained muscle weakness or fatigue, have digestive disorders affecting nutrient absorption, or notice symptoms like hair loss, white nail beds, or weakened immunity with frequent infections. Testing is particularly important if you follow a restricted diet, rely on total parenteral nutrition, or have undergone gastrointestinal surgery that affects nutrient absorption. Early detection through blood testing can prevent serious complications like heart disease and joint problems associated with prolonged selenium deficiency.
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What this means
Your testosterone levels are slightly below the optimal range. While this is not necessarily cause for concern, it may contribute to occasional fatigue, reduced motivation, or lower muscle mass over time.
Recommended actions
Increase resistance or strength training
Prioritize 7–8 hours of quality sleep per night, try to reduce stress
Include more zinc- and magnesium-rich foods (like shellfish, beef, pumpkin seeds, spinach)
Consider retesting in 3–6 months
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