Brazil nuts characterized by a high content in several bioactive substances, such as phenolic compounds, tocopherol, folate, magnesium, potassium, calcium, proteins and mono- (MUFA) and polyunsaturated (PUFA) fatty acids, but are best known as one of the major food sources of selenium
Selenium: trace element
Function: essential component of various enzymes and proteins. Important for reproduction, thyroid gland function, DNA production, protection against body damage caused by free radicals and from infection
Requirements: Healthy adults (male and female) – 55 mcg/day / Pregnancy: 60 mcg/day / Lactation: 70 mcg/day
Τolerable Upper Intake Levels (ULs) for Selenium: 400 mcg (healthy male and female adults)
The major dietary sources of selenium include Brazil nuts (68-91 mcg each) and fish
Selenium deficiency has serious complications and has been associated with male infertility, may predispose individuals experiencing additional stress to develop certain diseases, may play a role in types of osteoarthritis, and could exacerbate iodine deficiency, increasing the risk of cretinism in infants.
However, large amounts of selenium can cause toxicity with unwanted side effects such as a garlic smell on the breath, metallic taste in the mouth, loss or brittleness of hair and nails. Also, nausea, diarrhea, skin rashes, tooth spots, fatigue, irritability and nervous system abnormalities.
So...how many Brazil nuts to eat? Is there a limit?
1-2 brazil nuts a day and no more are recommended. With 4-5 we can reach toxic selenium levels for the body
References:
Godos, J., Giampieri, F., Micek, A., Battino, M., Forbes-Hernández, T. Y., Quiles, J. L., Paladino, N., Falzone, L., & Grosso, G. (2022). Effect of Brazil Nuts on Selenium Status, Blood Lipids, and Biomarkers of Oxidative Stress and Inflammation: A Systematic Review and Meta-Analysis of Randomized Clinical Trials. Antioxidants (Basel, Switzerland), 11(2), 403. https://doi.org/10.3390/antiox11020403
Cardoso, B. R., Duarte, G. B. S., Reis, B. Z., & Cozzolino, S. M. F. (2017). Brazil nuts: Nutritional composition, health benefits and safety aspects. Food research international (Ottawa, Ont.), 100(Pt 2), 9–18. https://doi.org/10.1016/j.foodres.2017.08.036
Office of dietary supplements - selenium (2021) NIH Office of Dietary Supplements. Available at: https://ods.od.nih.gov/factsheets/Selenium-HealthProfessional/ (Accessed: 24 October 2023).