NOW Brazil Nuts, also known as Para Nuts, are the seeds of a tropical tree (Bertholletia excelsa) native to the Amazon River basin of South America. They are unique in that they are the richest known food source of selenium, an important mineral that's an effective antioxidant. It's estimated that eating just one serving a day would prevent selenium deficiency! Brazil Nuts are also a good source of other minerals, including zinc and magnesium. The FDA recently approved the following health claim for Brazil Nuts: "Scientific evidence suggests, but does not prove, that eating 1.5 ounces per day of most nuts, such as Brazil Nuts, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease."