Barium Levels in Brazil Nuts: A Global Review of the Literature

Brazil nuts are often recommended for their high selenium content but have also been reported to contain elevated levels of barium, a potentially toxic element. Regular daily consumption of Brazil nuts may exceed the currently suggested tolerable daily intake (TDI) for barium (ca. 0.2 mg/kg body weight/day). No comprehensive review of barium levels in Brazil nuts has been published to date. Therefore, a global literature review of barium in Brazil nuts without language or time restrictions was conducted. A total of 24 eligible publications (1933-2023) were included. The literature review indicated a mean barium level of 1.27 (95% confidence interval: 0.89, 1.64; range: 0.03-5.89; n = 43) mg/g. For most regions, consuming two Brazil nuts per day does not exceed the TDI for adults. However, in some regions (Germany, Guyana, and Japan), and for individuals with a body weight of <60 kg, consuming two Brazil nuts per day may already exceed the TDI, not accounting for other dietary sources of barium. Studies with georeferencing are needed to clarify geographic variability, and human studies on barium bioavailability from Brazil nuts are warranted.