Too many Brazil nuts can cause poisoning

Too many Brazil nuts can cause poisoning

Pawel Malczewski
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Short summary

Brazil nuts contain high amounts of selenium. Eating more than 4 nuts daily, during a short period of time, may cause symptoms such as nausea, vomiting and diarrhea. Eating this amount on a regular basis may lead to selenosis. For a quick answer click here.

Explanation

Eating a large amount of Brazilian nuts for a prolonged period of time may lead to a condition known as selenosis, which arises due to the excessive amount of selenium in the blood. Very high amounts of selenium may be found in Brazil nuts. However, it varies depending on the region they come from, due to the amount of selenium in the soil in each region.

The maximum daily intake of selenium has been set for various age groups.

Tolerable Upper Intake Levels of selenium for different age groups. (1)U.S. Department of Health and Human Services. Selenium. Available here.

Age groupDaily upper limit (mcg)Amount of kernels
0 - 6 months45< 1
7 - 12 months60< 1
1-3 y901
4-8 y1501.5
9-13 y2803
14-18 y4004
19 y +4004

NOTE: one 5g Brazil nut kernel contains about 100mcg of selenium depending on its origins.

Please note that the maximum safe limit observed through studies was 800mcg of selenium per day. However, for safety reasons, the official upper limit became 400mcg. It is assumed that the intake of selenium above that limit may lead to selenosis.

Some common symptoms of an overdose of selenium are gastrointestinal discomfort, loss of hair, white and brittle nails, nausea, joint pain and fatigue.

However, there are other reasons why selenosis may occur, such as if you take selenium supplements or if you live in an area rich in selenium and consume foods with a selenium high content. (2)MacFarquhar JK, Broussar DL, Melstorn P, Hutchinson R, Wolkin A, Martin C, et al. Acute Selenium Toxicity Associated With a Dietary Supplement. Arch Intern Med. 2010 Feb 8; 170(3): 256–261. Available here. (3)Agency for Toxic Substances and Disease Registry. Public Health Statement for Selenium. Available here. (4)Schrauzer GN. Nutritional selenium supplements: product types, quality, and safety. J Am Coll Nutr. 2001 Feb;20(1):1-4. Available here. (5)Reid ME, Stratton MS, Lillico AJ, Fakih M, Natarajan R, Clark LC, Marshall JR. A report of high-dose selenium supplementation: response and toxicities. J Trace Elem Med Biol. 2004;18(1):69-74. Available here. (6)Senthilkumaran S, Balamurugan N, Vohra R, Thirumalaikolundusubramanian P. Paradise Nut Paradox: Alopecia Due to Selenosis from a Nutritional Therapy. Int J Trichology. 2012 Oct-Dec; 4(4): 283–284. Available here. (7)U.S. Department of Health and Human Services. Selenium. Available here.

Conclusion

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Certain foods contain high doses of a specific nutrient, which in high doses may cause negative health effects. A good example is the Brazil nut that contains an unusual amount of a mineral that, although it has great health properties, if taken in excess may cause considerable damage. This is why we should always make sure that our diet is balanced and we rotate foods on a regular basis. You should always be aware of the foods with an excessive amount of a specific nutrient.

References   [ + ]

1. U.S. Department of Health and Human Services. Selenium. Available here.
2. MacFarquhar JK, Broussar DL, Melstorn P, Hutchinson R, Wolkin A, Martin C, et al. Acute Selenium Toxicity Associated With a Dietary Supplement. Arch Intern Med. 2010 Feb 8; 170(3): 256–261. Available here.
3. Agency for Toxic Substances and Disease Registry. Public Health Statement for Selenium. Available here.
4. Schrauzer GN. Nutritional selenium supplements: product types, quality, and safety. J Am Coll Nutr. 2001 Feb;20(1):1-4. Available here.
5. Reid ME, Stratton MS, Lillico AJ, Fakih M, Natarajan R, Clark LC, Marshall JR. A report of high-dose selenium supplementation: response and toxicities. J Trace Elem Med Biol. 2004;18(1):69-74. Available here.
6. Senthilkumaran S, Balamurugan N, Vohra R, Thirumalaikolundusubramanian P. Paradise Nut Paradox: Alopecia Due to Selenosis from a Nutritional Therapy. Int J Trichology. 2012 Oct-Dec; 4(4): 283–284. Available here.
7. U.S. Department of Health and Human Services. Selenium. Available here.