From the Guidelines
Selenium is a crucial trace mineral necessary for human health, and adults should aim to consume 55 micrograms daily to support antioxidant defense, thyroid hormone metabolism, and immune function. The importance of selenium in human health is multifaceted, playing a key role in protecting cells from oxidative damage, supporting proper thyroid function, and enhancing immune response 1. Selenium deficiency can lead to health issues such as Keshan disease, impaired immune function, and increased susceptibility to infections, while excessive intake can cause selenosis, characterized by symptoms like hair loss, nail brittleness, and gastrointestinal upset 1.
Key Functions of Selenium
- Antioxidant defense: Selenium is a component of selenoproteins like glutathione peroxidase, which neutralize harmful free radicals.
- Thyroid hormone metabolism: Selenium facilitates the conversion of thyroid hormones to their active form.
- Immune function: Selenium enhances white blood cell function and reduces inflammation.
Dietary Recommendations
- Adults need 55 micrograms of selenium daily, which can be obtained from foods like Brazil nuts, seafood, meat, and whole grains.
- Most people in developed countries get adequate selenium through diet alone, making supplements unnecessary unless specifically recommended by a healthcare provider 1.
- High-dose selenium supplements are not recommended due to the narrow margin between safe and toxic dosages, with a maximum daily supplement dose of 200 micrograms 1.
Potential Health Risks
- Deficiency: Keshan disease, impaired immune function, and increased susceptibility to infections.
- Excess: Selenosis, with symptoms including hair loss, nail brittleness, gastrointestinal upset, and neurological issues, typically occurring with supplement intake exceeding 400 micrograms daily 1.
Given the potential for both deficiency and excess to cause health problems, it is essential to maintain an adequate selenium intake, preferably through a balanced diet rather than supplements, unless advised by a healthcare provider 1.
From the Research
Importance of Selenium in Human Health
Selenium is a essential trace element that plays a crucial role in maintaining human health. The importance of selenium can be understood from the following points:
- Selenium is necessary for the proper functioning of the thyroid gland, and its deficiency can lead to thyroid-related disorders 2.
- Selenium acts as an antioxidant in the body, protecting cells from damage caused by free radicals and reactive oxygen species 3, 4.
- Selenium deficiency has been linked to various diseases, including cancer, heart disease, and metabolic disorders 3, 4, 5, 6.
- Selenium is essential for the synthesis of selenoproteins, which are involved in various cellular processes, including antioxidant defense and redox control 2, 3.
Role of Selenium in Disease Prevention
Selenium has been shown to play a role in the prevention of various diseases, including:
- Keshan disease, an endemic heart disease caused by selenium deficiency 6.
- Kashin-Beck disease, a joint and bone disease that has been linked to selenium and iodine deficiency 5.
- Cancer, with selenium deficiency increasing the risk of certain types of cancer 3.
- Metabolic disorders, such as hyperlipidaemia, hyperglycaemia, and hyperphenylalaninemia, which can be managed with selenium supplementation 4.
Selenium Deficiency and Health Risks
Selenium deficiency can have serious health consequences, including: