In the United States, soils in the high plains of northern Nebraska and the Dakotas are particularly rich in selenium. People living in these regions typically have higher dietary selenium levels than those in other parts of the country. Conversely, in some parts of China and Russia, soils are severely depleted of selenium. Populations in these areas often experience dietary deficiencies that can lead to serious health problems, such as Keshan disease—a potentially fatal heart condition first identified in selenium-poor regions of China.
While plants are the foundational source of selenium in the food chain, animal products also contribute significantly. Livestock that consume grains or forages grown in selenium-rich soils tend to accumulate higher levels of the mineral in their tissues. Consequently, meats, eggs, and seafood can be valuable dietary sources of selenium. In the United States, meats and bread provide much of the population’s selenium intake, reflecting the country’s selenium-rich agricultural soils and fortification practices.
Among plant-based foods, nuts—especially Brazil nuts—stand out as exceptionally rich sources. A single Brazil nut can supply more than the daily recommended intake of selenium. Walnuts and other nuts also contain meaningful amounts, making them beneficial additions to a balanced diet. Recent studies emphasize the role of selenium in supporting immune function, thyroid health, and antioxidant defense, underscoring the importance of maintaining adequate intake through diverse, nutrient-rich foods.
Selenium in the Diet: How Soil Shapes Nutritional Health
