Thyroid hormone metabolism
Selenium contributes to this process as part of a balanced pattern of nutrients and healthy body function.
Vitamins & Minerals
Selenium
This page is for education only and does not diagnose or treat a deficiency. Symptoms can have many causes, and laboratory testing may be needed to confirm a nutrient problem.
What Is This Nutrient?
Selenium is a trace mineral. The body needs it to carry out essential processes, and an appropriate intake supports normal health without replacing individualized medical care.
Primary Functions
Antioxidant protection
Selenium contributes to this process as part of a balanced pattern of nutrients and healthy body function.
DNA production and immune function
Selenium contributes to this process as part of a balanced pattern of nutrients and healthy body function.
Foods Rich In Selenium
Excellent Sources
- Brazil nuts
- Tuna
- Sardines
Good Sources
- Shrimp
- Turkey
- Cottage cheese
Additional Sources
- Eggs
- Brown rice
- Whole-wheat bread
Food amounts vary by variety, soil, fortification, brand, preparation, and portion size.
Ways To Support Healthy Levels
Use varied seafood, meats, eggs, dairy, and grains. Brazil nuts are concentrated, so more is not necessarily better.
A varied eating pattern is usually the best foundation. Supplements can be useful in specific situations, but the right form and dose depend on age, diet, health conditions, medications, pregnancy, and laboratory results.
Possible Signs Of Deficiency
Possible signs may include:
- Deficiency alone rarely causes illness
- It may worsen thyroid or heart problems in susceptible people
These symptoms can have many causes and do not confirm a deficiency. Consider discussing persistent or concerning changes with a healthcare professional.
Possible Risk Factors For Deficiency
- Living in very low-selenium soil regions
- Kidney dialysis
- HIV infection or certain absorption problems
Restricted diets, digestive disorders, aging, medical conditions, and certain medications can change nutrient needs or absorption. Individual assessment matters.
Possible Signs Or Risks Of Excess Intake
- Hair or nail loss, metallic taste, garlic breath, nausea, or nerve changes
- Brazil nuts and supplements can make excess intake easier
Food and supplements are not interchangeable sources of risk. Keep supplements away from children and follow product labels and professional advice.
When To Speak With A Healthcare Professional
Persistent Symptoms
Discuss ongoing fatigue, weakness, pain, digestive changes, or other symptoms rather than assuming they come from one nutrient.
Neurological Or Heart Symptoms
Promptly seek care for new numbness, severe weakness, confusion, balance changes, fainting, or heart-rhythm concerns.
Supplement Questions
Ask about the appropriate dose, medication interactions, medical conditions, pregnancy, and whether laboratory testing is useful.
Frequently Asked Questions
Can food provide enough?
Often, yes, but needs and absorption vary. Fortified foods or supplements may be appropriate for some diets, life stages, and medical situations.
Should I take a supplement for symptoms?
Symptoms alone cannot identify a deficiency. A healthcare professional can help evaluate causes, testing, and a safe plan.
Can more be harmful?
Yes. Some nutrients interact with medicines or become harmful at high doses. Avoid assuming that a larger dose is better.
Related Articles
More Selenium articles, deficiency guides, food guides, and practical worksheets are coming soon.
Related Resources
Source note: This educational overview is informed by the NIH Office of Dietary Supplements consumer fact sheet for Selenium. Consult qualified healthcare professionals for diagnosis, laboratory testing, treatment, or supplement decisions.