Although considered exotic food, unusual in the most countries, Brazilian walnut increasingly can be seen on the stands as part of mixed package with other nuts or in separate peckage. In fact, these nuts have very high content of selenium in them. Actually, this is the richest food of selenium that we know.

Selenium is a biologically active substance. It helps to protect the body’s organs from oxide stress. It also affects the immune system processes related to the protection and recovery of infections. Moreover, it helps to regulate the growth.
Ensuring minimum recommended average daily intake of selenium from food will help your health and proper functioning of many processes in the body. At the same time, if you intake it for a long period of time in large doses /over 300 micro g per day/, it could be harmful for you.
A single intake of high dose of selenium could cause nausea, vomiting, diarrhea, irritability. The intake of high doses of selenium long time could lead to a condition called SELENOSIS, which is characterized by loss / hair loss, brittle nails and loss, numbness and other odd sensations in the limbs / neurological anomalies.
Considering the Brazilian walnut and the selenium in it, the most correct definition is that the dose makes the drug. Small quantities / 1-2 nuts daily / can provide the minimum recommended intake of selenium for adult and chronic intake of large quantities could harm you.
The content of selenium in Brazilian walnut is 1917 micro g per 100g/3.53 oz. The recommended minimum amount of selenium for adult is 55 micro g and intake over 250-300 micro g considered a risk to the health.

Using these data, the minimum recommended amount of selenium we would secured approximately 3g /a nut daily/0.10 oz.

Prolonged intake of daily quantities above 15 g / 0.53 oz is considered a risk to the health.

Our recommendation is to try to provide you the required amount of selenium by a varied and balanced diet; and also not to consume food in quantities which are known to be dangerous to your health.