Understanding Selenium Side Effects: Risks and Precautions

Selenium is an essential mineral that the human body requires in small amounts for various physiological functions. While selenium plays an important role in supporting immune function, thyroid health and antioxidant defense mechanisms, consuming too much selenium can have adverse health effects. Understanding the side effects of selenium, their causes, and how to prevent them is essential to maintaining optimal health.

selenium side effects

Importance of Selenium:

Selenium acts as a cofactor for several enzymes involved in antioxidant defense mechanisms, thyroid hormone metabolism, and immune function. Adequate selenium intake is essential to maintain overall health and prevent selenium deficiency. However, excessive selenium intake can have toxic effects on the body, causing selenium toxicity or selenosis.

Common Selenium Side Effects:

  • Gastrointestinal distress: Taking high doses of selenium supplements may cause gastrointestinal discomfort, including nausea, vomiting, diarrhea, and stomach pain. These symptoms usually occur when selenium intake exceeds the body's ability to absorb and utilize it.

  • Changes in hair and nails: Excessive selenium intake can cause changes in the health of hair and nails. Symptoms may include hair loss, brittle hair, and changes in nail texture and color. These effects are often reversible once selenium intake is reduced to appropriate levels.

  • Skin problems: Selenium toxicity can manifest as skin reactions including rash, itching, and burning. In severe cases, selenium toxicity can cause dermatitis or skin lesions.

  • Neurological symptoms: High selenium levels can affect neurological function, causing symptoms such as dizziness, confusion, and nerve damage. Chronic selenium toxicity can result in peripheral neuropathy, which is characterized by numbness, tingling, and weakness in the limbs.

  • Difficulty breathing: In rare cases, excessive selenium intake can cause respiratory problems, including difficulty breathing, chest tightness, and cough. Severe selenium toxicity can result in pulmonary edema, which is potentially life-threatening.

  • Cardiovascular effects: Selenium toxicity can also affect cardiovascular health, causing irregular heartbeats (arrhythmias), elevated blood pressure, and in extreme cases, cardiac collapse.

Causes of Selenium Toxicity:

  • Selenium toxicity typically occurs when individuals consume excessive amounts of selenium from dietary sources or supplements. Some factors can increase the risk of selenium toxicity, including:

  • High selenium soils: In areas where selenium levels in the soil are naturally high, plants and crops can absorb increased amounts of selenium, leading to higher selenium content in foods.

  • Supplements: Taking selenium supplements in doses higher than recommended levels may increase the risk of selenium toxicity. It is important to follow healthcare provider recommendations and not exceed recommended selenium intake levels.

  • Industrial exposure: Individuals working in industries such as mining, metal processing, or manufacturing may be exposed to high levels of selenium through environmental pollution, increasing the risk of selenium poisoning.

Prevention and Precautions:

To prevent selenium toxicity and reduce the risk of side effects, consider the following precautions:

  • Moderate selenium intake: Consume selenium from dietary sources in moderation, with the goal of meeting recommended dietary allowances (RDAs) without exceeding safe upper limits.

  • Consult health care professionals: Before starting selenium supplementation, consult a health care professional to determine if supplementation is necessary and to determine appropriate dosage levels.

  • Be mindful of selenium content: Be mindful of selenium content in foods and supplements to avoid excessive intake. Brazil nuts, seafood, organ meats and some grains are rich sources of selenium.

  • Keep an eye on symptoms: Pay attention to any unusual symptoms or health changes that may indicate selenium toxicity. If you experience adverse effects, seek medical help immediately.

While selenium is essential to support various bodily functions, excessive selenium intake can have adverse health effects. It is important to understand the side effects of selenium, their causes, and how to prevent them to maintain optimal health. By practicing moderation, being mindful of selenium intake, and consulting health professionals when needed, individuals can reduce the risk of selenium toxicity and promote overall health and well-being.