People in Galicia, Spain, who eat more seafood tend to have higher levels of selenium in their blood, and those with sufficient selenium levels typically eat about four servings of fish per week.

People in Galicia, Spain, who eat more seafood have higher levels of selenium—a beneficial nutrient—as well as higher levels of toxic elements like arsenic and mercury in their blood, because seafood contains both.

Brazilian adults who drink alcohol tend to consume about 4.38 micrograms more selenium per day than those who do not drink, likely because their diets include more selenium-rich foods like meat and fish.

In healthy adults from Galicia, Spain, people who consume more dietary oil tend to have lower levels of selenium in their blood, which may be related to how fat in the diet affects selenium absorption or reflects broader dietary habits.

In healthy adults from Galicia, Spain, the amount of selenium in the blood changes more noticeably with dietary intake than the levels of zinc, copper, or iron, which stay relatively constant due to biological regulation. This makes selenium a more reliable indicator of whether dietary intake is sufficient.

In Brazilian adults, the majority of selenium intake comes from nuts, cooked fish, and boneless meat, with nuts providing nearly 29% of total selenium consumption.