Plasma Concentration of Essential and Toxic Trace Elements After Brazil Nut Intake: Results from a Randomized Controlled Trial

Brazil nut (BN) is a good source of essential nutrients, but little is known about the content of other components, such as toxic elements. Moreover, the high consumption of BN could probably contribute to increased levels of toxic and essential elements in the blood. Thus, this study aimed to evaluate the concentration of essential and toxic trace elements in BN and their concentration in plasma of obese women after regular intake of BN. A randomized controlled clinical trial was carried out with 55 subjects that were randomly assigned to either the Brazil nut group (BN) ( n = 29) or the control group (CO) ( n = 26) and followed up for 2 months. The BN group consumed one unit of Brazil nut per day, and the CO group did not receive any intervention. The concentration of essential elements (zinc, copper, manganese, and cobalt) and toxic (barium, lead, and cadmium) in BN samples and plasma of obese women (before and after the intervention) were determined by inductively coupled plasma mass spectrometry. Barium followed by copper, and manganese were the trace elements present in higher amounts in Brazil nuts. After the BN intervention period was observed an increase in plasma cadmium ( p = 0.002) and a reduction of plasma manganese ( p < 0.001) levels. In conclusion, our findings suggest that the regular consumption of BN from the Brazilian Amazon rainforest contributes to the intake of essential trace elements and can be considered safe regarding the content of heavy metals.