Inorganic Constituents of Nuts and Seeds

Publisher Summary This chapter provides an evaluation of the nutritional and toxicological significance of different types of nuts and seeds in the human diet. Nuts and seeds are rich in essential elements, consisting of both macro elements and trace elements or “micronutrients” with requirements of no more than a few milligrams per day. Nut consumption is associated with protection against bone demineralization, arterial hypertension, insulin resistance, and overall cardiovascular risk. Nuts are nevertheless referred to as the best dietary source of manganese and a good source of boron, especially for vegetarians. Sunflower seeds, and especially Brazil nuts, are rich sources of dietary selenium, though extremely high concentrations reported for Brazil nuts from some geographical areas raise overconsumption concerns. Nuts and seeds contain very low concentrations of most toxic and potentially toxic elements, such as silver, aluminum, antimony, tin, tellurium, thorium, and uranium. Relatively high arsenic, lead, and mercury concentrations reported in some studies for selected nuts and seeds are likely the result of contamination or analytical errors. Even essential elements may become harmful when their ingestion rates are excessive, resulting in adverse physiological effects. Other elements have no physiological benefits at all and are recognized as being toxic for humans.