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Selenium: foods, benefits & RDA

Siski Green / 19 April 2022

Selenium is one of those minerals you may not be as familiar with as zinc, iron or calcium but it’s just as important for your health.

Brazil nuts in a jar
Bazil nuts can contain large amounts of selenium

What is selenium used for?

Selenium is an essential mineral and vital for your overall health. It’s an antioxidant so helps protect you against oxidative stress which can damage healthy cells; it’s protective against cancer and heart disease; and it’s also essential for healthy thyroid function (and so maintaining healthy metabolism, for example); and it also keeps your immune system in good shape.

What’s the best way to take selenium and does it work?

Most studies of selenium and its benefits have been based on people who get their selenium via diet, so ideally that’s how you’d get yours too. Good sources include tuna, sardines, chicken breast, sunflower seeds, Brazil nuts, oysters and shiitake mushrooms. Garlic, onions, broccoli, celery and tomatoes also contain selenium.

It is however important to note that with certain foods where they are farmed dramatically affects how much selenium they contain. In one study of Brazil nuts, some were found to contain around three times the recommended daily amount, while others contained just 10%. This is because the soil may not contain sufficient selenium – rainfall and pH levels can affect how much selenium soil contains which obviously varies by region – and as a result the plants grown in it don’t absorb as much.

If you aren’t getting enough selenium – the RDA is 60mcg for women and 75mcg for men – you may present with certain symptoms and effects such as muscle weakness, fatigue, hair loss and weakened immune system. Low selenium levels are slightly more common in older people (along with smokers and vegetarians). If you think this might be the case see your doctor to discuss options for tests and/or treatment.

Where can I get selenium?

Getting selenium via your diet is ideal – the best sources are seafood or nuts – and certain foods, such as pasta, bread and cereals are also often enriched with selenium along with other minerals (check the label). But you can also take a supplement of 200mcg per day, available at supermarkets and healthfood shops.

What are the side effects and contraindications of taking selenium?

Getting selenium via your diet is unlikely to cause excess intake, but it is possible to ingest too much via supplements (more than 400mcg per day). Too much may cause dizziness, facial flush, hair loss, nausea and/or vomiting.

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The opinions expressed are those of the author and are not held by Saga unless specifically stated. The material is for general information only and does not constitute investment, tax, legal, medical or other form of advice. You should not rely on this information to make (or refrain from making) any decisions. Always obtain independent, professional advice for your own particular situation.