Survey data suggests hair loss is a common occurrence, with nearly a third of men or women believed to suffer from some degree of baldness or alopecia. Most treatments for hair loss come with downsides, so many resort to natural ingredients to promote new growth. Certain foods, such as nuts, may help reverse hair loss, but consuming excessive amounts of one nut could have devastating effects.
Brazil nuts are a good source of selenium, which has qualities known to prevent hair loss.
“Brazil nuts are an excellent source of selenium, a mineral that may help boost hair growth,” notes Medical News Today.
The health body continues: “However, too much selenium can cause brittle hair and hair loss, along with nausea, skin rashes, and nervous system problems.
“The recommended upper limit for selenium in adults is 400 micrograms. Brazil nuts are very rich in selenium – one brazil nut offers 69-91 mpg – so people may wish to limit their intake to around four Brazil nuts per day.”
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The BBC reports that as a whole, the nut is safe to eat, but overconsumption can lead to selenosis, which can cause devastating hair loss.
These toxic effects have been reported in a string of medical studies, highlighting the need for cautious intake of brazil nuts.
One case report, published in the International Journal of Trichology, reported on a 55-year-old woman who presented with headaches, dizziness, vomiting and abdominal pain for 5 days.
On the second day of her hospital admission, doctors noted the patient had lost a significant number of scalp hairs on her pillow.
“This process started abruptly but was unremitting, and she noted shedding of hairs in tufts while combing or even gently pulling her hair,” wrote the authors of the paper.
“Even a gentle pull of hair caused painless extractions of a bunch of hairs, typically comprising more than 50 hairs.
“Other body hairs were spared and were normal in thickness.
“Within two days, most of the hair on her scalp had fallen out and she became totally bald. She also had developed greying discolouration of the fingernails on the 4th hospital day.”
Test results revealed the patient’s plasma level of selenium was at 512 mg/L. Normal plasma selenium levels should range between 74-139 mg/L.
Researchers say the case is one of more than 200 to have taken place in the same period, highlighting the pressing need to explore dietary sources as causes of toxicity.
“Just because nuts are natural products, they may not necessarily be safe or good when consumed in large, uncontrolled amounts,” warned the authors.
“Public health education efforts should focus on the real and proven benefits as well as adverse effects of nutritional supplements and alternative therapies, in order to prevent untoward effects on vulnerable and gullible patients.”
Other low concentration sources of selenium include meat, liver, fish, eggs, milk, bread and cereals.