Brazil nuts are considered the best dietary source of selenium, containing up to ten times the recommended daily intake in one ounce. They are a source of fat, 34% of which is monounsaturated, 41% of which is polyunsaturated, and 25% of which is saturated. Brazil nuts may lead to kidney stone formation in susceptible persons due to their content of oxalates.
As a tree nut, brazil nuts can be considered a common allergen. Routinely exceeding the tolerable upper intake for selenium is not recommended, something easily accomplished by consuming as few as four Brazil nuts on a daily basis.