Incredibly, eating just four nuts a day could help your health.
A study showed that selenium could help prevent one type of cancer while also having other health benefits.
The research suggests that limiting the antioxidant effects of a mineral called selenium may help to prevent the spread of triple-negative breast cancer by starving cancer cells.
Eating three or four nuts a day could help to lower cholesterol and inflammation, reports Surrey Live.
Selenium is found in Brazil nuts, meat, mushrooms, and cereal.
The research, published in EMBO Molecular Medicine, shows that when triple-negative breast cancer cells are not clustered together, such as when they move to other parts of the body, they cannot survive without selenium.
“Selenium is a trace element found in soil,” explains Dr Carrie Ruxton, a dietitian at the Health and Food Supplements Information Service.
“In the body, selenium is well absorbed and is used to make a protein building-block (amino acid) called selenocysteine. 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.”
In the UK, selenium is best found in animal foods such as turkey thigh, beef and fish but Brazil nuts are the richest source.
Alternatively, you can top up with a multivitamin or mineral supplement which can provide selenium.
The nutrient is also known for maintaining thyroid function, says Lucy Diamond, registered dietitian and clinical director for Innovation at NHS weight management provider, Oviva.
Other studies have found selenium may also help to lower cholesterol.
“According to studies, selenium can help to protect against cardiovascular disease by lowering ‘bad’ cholesterol and inflammation,” says Ruxton.
“There may also be a role in cancer prevention and protecting against cognitive decline, but the evidence is inconsistent.”
Despite these health benefits, too much selenium can also be bad for you, says Ms Diamond. It can lead to a condition called selenosis which can have symptoms of hair loss, brittle nails and digestive issues.
To maintain a healthy level of selenium, Ms Diamond said: “Men aged 19-64 years are recommended 75mcg a day and women aged 19-64 years are recommended 60mcg a day per day, but that amount can vary slightly depending on life stages, such as pregnancy or breastfeeding.
“Not getting enough selenium can lead to issues like weakened immunity or cognitive changes, though deficiency is fairly rare.”
The upper limit is 400mcg per day so this is important to bear in mind.
Eating three or four Brazil nuts a day should be the right amount.