Selenium Deficiency

Selenium deficiency happens when your body does not have enough selenium, an essential mineral that supports your immune system, thyroid function, and cellular health. Selenium acts as an antioxidant, which means it protects your cells from damage. Your body cannot make selenium on its own, so you must get it from food or supplements.

This deficiency is rare in most developed countries because soil contains enough selenium to support healthy food sources. However, people in certain geographic regions with selenium-poor soil face higher risk. China has documented cases of severe selenium deficiency causing specific diseases.

When selenium levels drop too low, your body struggles to perform essential functions. Severe deficiency can lead to Keshan disease, a type of heart disease that can progress to heart failure. It may also contribute to Kashin-Beck disease, a form of osteoarthritis affecting bones and joints. Most cases of selenium deficiency develop slowly over time.

• Muscle weakness and fatigue that does not improve with rest
• Hair loss or brittle, thin hair
• Weakened immune system with frequent infections
• Mental fog or difficulty concentrating
• Hypothyroidism symptoms like weight gain and cold sensitivity
• Joint pain and stiffness, especially in Kashin-Beck disease
• Heart problems including irregular heartbeat or chest pain
• Pale or discolored nail beds
• Fertility issues in both men and women

Many people with mild selenium deficiency have no obvious symptoms early on. The body prioritizes selenium for critical functions, so symptoms may not appear until levels drop significantly. Severe deficiency symptoms develop gradually over months or years.

Selenium deficiency most often occurs in regions where soil contains very low selenium levels. When plants grow in selenium-poor soil, they cannot absorb enough of the mineral to pass along through the food chain. Geographic areas in parts of China, Tibet, and Siberia have documented severe deficiency cases. People who rely solely on food grown in these areas face the highest risk.

Certain health conditions increase your risk of selenium deficiency. Digestive disorders like Crohn's disease, celiac disease, and ulcerative colitis can impair selenium absorption in your intestines. People who have undergone gastric bypass surgery may also struggle to absorb enough selenium. Those receiving long-term intravenous feeding without proper supplementation can develop deficiency. Kidney dialysis patients lose selenium during treatment and may need extra intake. Smoking and heavy alcohol use can deplete selenium levels over time.

Healthcare providers diagnose selenium deficiency through specialized blood or urine tests that measure selenium levels in your body. Blood tests show your current selenium status, while 24-hour urine tests reveal how much selenium your body is excreting. Low urine selenium levels may indicate deficiency and insufficient dietary intake.

These specialized tests are not part of routine health panels. Your doctor will order selenium testing if you have symptoms suggesting deficiency or risk factors like digestive disorders. Talk to a healthcare provider about testing if you experience unexplained muscle weakness, hair loss, or heart symptoms. They can help determine if specialized selenium testing is right for you.

• Eat selenium-rich foods like Brazil nuts, which contain very high amounts in just one or two nuts daily
• Include seafood such as tuna, halibut, sardines, and shrimp in your diet regularly
• Add organ meats like liver and kidney, which are excellent selenium sources
• Consume whole grains, eggs, and poultry to support adequate intake
• Take selenium supplements only under medical supervision to avoid toxicity
• Address underlying digestive disorders that impair selenium absorption
• Work with a registered dietitian to plan a selenium-adequate eating pattern
• Monitor selenium levels through follow-up testing after starting treatment
• Avoid excessive supplementation, as too much selenium can be toxic