How to tell if you're deficient in key antioxidant selenium

You may be deficient in an essential mineral called selenium and have no idea - but the good news is it’s in a ton of our foods, making it really easy to start hitting your daily intake goal.

Present in soil, water, some foods, and available in supplement form, selenium is absorbed by the body to make a protein-building block called selenocysteine, explained Dr Carrie Ruxton, a dietitian at the Health and Food Supplements Information Service.

“Proteins made from this amino acid are vital for normal thyroid function, immunity, fertility, and also protecting the body against cancers and cell damage due to toxins,” she told The Independent.

In many countries, eating cereals grown in selenium-rich soil is enough.

But in the UK, where there are low levels of the key element in the ground, we can get our fill by turning to meats, such as turkey and beef.

Eggs, grass-fed meats and diary products like cottage cheese are all a good source of selenium (Getty Stock Image)

Cottage cheese and eggs are also good sources of the nutrient.

British adult men should consume 75 mcg of the key element per day, while adult women should stick to 60 mcg, according to the NHS.

But how do you know if you’re not getting enough of the mineral?

Selenium deficiency signs

While selenium deficiency is rare, it’s not an impossible health issue to encounter, with research estimating that up to one billion people across the globe are affected by insufficient selenium intake.

Low selenium levels can lead to ‘weakened immunity, cognitive decline, muscle weakness, infertility, and thyroid dysfunction - and in severe cases it can also contribute to an increased risk of chronic diseases and heart disease’, nutritional therapist Farzanah Nasser told Vogue.

Mental fog, difficulty concentrating, and memory problems are also key signs of selenium deficiency, as per Thyroid UK.

Best foods to combat selenium deficiency

If you’re deficient in selenium, then there are certain foods lauded for containing an abundance of the antioxidant, as per BBC Good Food.

• Bread containing selenium yeast
• Certain grass-fed meats - beef steak, turkey, and chicken
• Fish like yellowfin tuna
• Milk
• Brazil nuts
• Baked beans
• Sunflower seeds

Eating food products rich in selenium or taking supplements could help elevate your brain fog (Getty Stock Image)

Too much selenium can be bad

Like everything, too much of a good thing can be detrimental to your health.

High amounts of the mineral can cause severe stomach and nervous system problems, difficulty breathing, tremors, and lightheadedness, according to the National Institutes of Health’s Office of Dietary Supplements.

That’s why, according to Nasser, ‘consuming just the right amount is incredibly important, and supports smaller yet vital elements of the body such as glutathione peroxidase enzymes, which protect your cells.’

A previous study also suggested that limiting selenium in your diet could help prevent the spread of triple-negative breast cancer.

The research, published in EMBO Molecular Medicine, showed that when triple-negative breast cancer cells are not clustered together, they cannot survive without selenium.

Dr Saverio Tardito, of the Cancer Research UK Scotland Institute in Glasgow, explained that while removing selenium from our diet was not ‘an option’, if a treatment can be found that ‘interferes with the uptake of this mineral by triple negative breast cancer cells, we could potentially prevent this cancer spreading to other parts of the body.’

Selenium supplements

If you suspect you have a selenium deficiency, a medical expert may suggest you start taking the antioxidant in pill form.

A doctor will be able to safely guide you through a supplementation plan and monitor your levels over time, nutritional therapist Eve Kalinik told Vogue.