Understanding Excess Selenium (Selenosis)
Selenosis is the term for selenium toxicity, which happens when the body has too much selenium. Although selenium is essential for health, including metabolism and thyroid function, too much can be harmful. Selenosis is uncommon and usually results from taking too many supplements or eating large amounts of foods very high in selenium. Selenium levels in plants can also vary based on the soil where they grow.
Causes and Risk Factors
High selenium intake, exceeding the 400 mcg daily UL for adults, can lead to toxicity.
- Dietary Supplements: Taking high-dose supplements is the most frequent cause. An incident in 2008 involving a supplement with extremely high selenium led to many selenosis cases.
- High-Selenium Foods: Eating certain foods regularly can cause overload. Brazil nuts are particularly high, with one nut potentially containing 68–91 mcg. Other sources include organ meats, some seafood, and grains.
- Environmental Exposure: Rarely, exposure can come from areas with high selenium in soil or water, as seen historically in parts of China. Occupational exposure is also a risk.
Recognizing the Symptoms
Symptoms of excess selenium vary with the amount and duration of exposure.
- Garlic breath: A recognizable garlic odor on the breath is a classic sign.
- Digestive issues: Nausea, vomiting, and diarrhea are common initially.
- Hair and nail changes: Hair loss, brittle nails, and lines on nails can indicate chronic exposure.
- Fatigue and irritability: Tiredness and mood changes may occur.
- Nerve issues: Tingling or numbness in hands and feet (peripheral neuropathy) can signal nerve damage.
- Skin problems: Rashes or lesions can develop.
Steps to Get Rid of Excess Selenium
Managing selenosis involves stopping the source of excess and providing supportive care. There is no specific antidote.
Immediate Action: Stop the Source
Immediately eliminate all sources of high selenium intake.
- Stop Supplements: Discontinue any supplements containing selenium.
- Reduce High-Selenium Foods: Avoid foods known for high content, especially Brazil nuts.
- Identify Environmental Sources: Investigate and address potential environmental exposure from water or local foods if suspected.
Dietary Adjustments for Reducing Selenium
Eating foods lower in selenium is important for recovery. The selenium content of foods can vary, so a varied diet is key. Most people get enough selenium from a balanced diet.
Focus on low-selenium foods:
- Fruits (peaches, bananas, apples)
- Many vegetables (carrots, lettuce, peas)
- Dairy alternatives
- Refined grains (white bread, pasta)
Limit or avoid high-selenium foods temporarily:
- Brazil nuts
- Some seafood (yellowfin tuna, sardines, shrimp, oysters)
- Organ meats (beef or chicken liver)
- Pork and beef steak
- Eggs
The Role of Supportive Care
For mild to moderate cases, treatment focuses on support while the body eliminates the excess. Recovery typically takes weeks to months after removing the source.
- Hydration: Drink more fluids to help remove excess minerals.
- Symptom Management: Treat symptoms like skin rashes or digestive issues as they occur.
- Medical Monitoring: Regular check-ups and blood tests are needed to ensure selenium levels return to normal.
Comparison: High vs. Low Selenium Foods
| Food Source | Typical Selenium Content | Key Consideration for Toxicity |
|---|---|---|
| High-Selenium Foods | ||
| Brazil Nuts (1-2) | ~68-91 mcg | High Risk: Easily causes toxicity if consumed regularly due to extremely high concentration. |
| Yellowfin Tuna (3 oz) | ~92 mcg | Moderate Risk: Regular, large portions can contribute significantly to daily intake. |
| Sardines (3 oz) | ~45 mcg | Moderate Risk: High concentration, important to monitor portion sizes. |
| Pork Chops (3 oz) | ~37 mcg | Low-to-Moderate Risk: A single serving is well below UL, but can contribute to high overall intake. |
| Beef Liver (3 oz) | ~28 mcg | Low-to-Moderate Risk: Good source, but less potent than nuts or some fish. |
| Low-Selenium Foods | ||
| Peaches (raw, 1 med) | 0 mcg | Low Risk: Contributes minimally to selenium intake. |
| Carrots (raw, ½ cup) | 0 mcg | Low Risk: Contributes minimally to selenium intake. |
| Lentils (1 cup) | ~6 mcg | Low Risk: A safe choice for daily intake. |
| White Bread (1 slice) | ~6 mcg | Low Risk: Low concentration, less reliant on soil variability than whole grains. |
Medical Guidance and Monitoring
If you suspect selenosis, see a doctor. They can order blood or urine tests to measure selenium levels. This helps confirm diagnosis and track recovery. Symptoms can be similar to other conditions, so medical confirmation is vital. Diagnosis is usually based on symptoms, intake history, and lab results. Severe cases might need intravenous fluids. Chelation therapy is not recommended for selenosis. For more information on mineral intake, visit the NIH Office of Dietary Supplements: https://ods.od.nih.gov/factsheets/Selenium-Consumer/.
Conclusion
The best way to deal with excess selenium is to stop the source, usually supplements or high-selenium foods like Brazil nuts. By staying below the UL, making careful food choices, and getting medical advice and monitoring, you can safely lower your selenium levels and recover from selenosis. Balanced nutrition is key; selenium is necessary, but too much can have negative effects.
