What Are Trace Minerals?
Trace minerals — also called trace elements — are minerals the body requires in very small amounts, typically measured in milligrams or micrograms per day. Despite their tiny required quantities, they are essential: the body cannot function properly without them, and it cannot manufacture them on its own. They must come from food.
This distinguishes them from major minerals (like calcium, magnesium, and potassium), which are needed in larger daily quantities. Trace minerals include zinc, selenium, iodine, iron, copper, manganese, chromium, molybdenum, and fluoride, among others. To understand how trace minerals fit into the broader picture of micronutrition, see our guide to what micronutrients do inside your body.
| Definition | Minerals needed in milligram or microgram quantities daily |
| Examples | Zinc, selenium, iodine, iron, copper, manganese, chromium |
| Adult zinc RDA (men) | 11 mg/day (National Institutes of Health, Office of Dietary Supplements) |
| Adult selenium RDA | 55 mcg/day (National Institutes of Health, Office of Dietary Supplements) |
| Adult iodine RDA | 150 mcg/day (National Institutes of Health, Office of Dietary Supplements) |
| Best whole-food zinc source | Oysters |
| Best whole-food selenium source | Brazil nuts |
| Primary iodine source (U.S.) | Iodized table salt, dairy, seafood |
Key Trace Minerals: Functions and Food Sources
Each trace mineral fills a distinct biological role. Here is a closer look at the most nutritionally significant ones:
Zinc
Zinc supports immune cell development, wound healing, protein synthesis, and DNA production. It also plays a role in taste and smell perception. Reliable food sources include oysters (one of the richest known sources), beef, pumpkin seeds, chickpeas, and fortified cereals. Vegetarians and vegans may absorb zinc less efficiently due to phytates in plant foods — a topic explored in our article on meeting micronutrient needs on a plant-based diet.
Selenium
Selenium is a component of selenoproteins, which act as antioxidants and help regulate thyroid hormone metabolism. Just one or two Brazil nuts per day can meet the adult daily requirement — though consistency matters more than large occasional doses. Other sources include tuna, sardines, eggs, and whole grains. Soil selenium content varies by region, which affects the selenium level in locally grown crops.
Iodine
Iodine is critical for thyroid hormone production, which governs metabolism, brain development, and energy regulation. Iodized table salt became a major public health intervention in the U.S. after widespread iodine deficiency was recognized in the early 20th century. Seafood, dairy products, and eggs also contribute meaningful iodine.
Iron
Iron enables red blood cells to carry oxygen throughout the body and supports energy metabolism. It exists in two dietary forms: heme iron (from animal products, more readily absorbed) and non-heme iron (from plant sources, absorption enhanced by vitamin C). Red meat, poultry, lentils, spinach, and tofu are common sources.
Copper
Copper helps the body use iron, supports connective tissue formation, and plays a role in nerve function and antioxidant defense. Liver, shellfish, nuts, seeds, and whole grains are copper-rich foods.
Manganese
Manganese contributes to bone development, carbohydrate metabolism, and antioxidant enzyme activity. Whole grains, legumes, nuts, and leafy vegetables are dependable sources for most people.
Getting the Balance Right
Because trace minerals are needed in such small amounts, most people who eat a reasonably varied diet consume adequate quantities without deliberate tracking. Deficiencies are more common in populations with restricted diets, food insecurity, certain chronic conditions, or increased physiological demands such as pregnancy.
It is equally important to recognize that more is not better. Several trace minerals — including selenium, iron, and zinc — can be harmful in excessive amounts. The USDA and NIH establish Tolerable Upper Intake Levels (ULs) for this reason. Supplementing beyond your actual needs carries real risk, a point addressed in our overview of common micronutrient myths.
Trace mineral
A mineral required by the body in very small amounts — typically milligrams or micrograms daily — that is nonetheless essential for normal physiological function.
Selenoprotein
A class of proteins that incorporate selenium as a structural component. Many selenoproteins function as antioxidants or are involved in thyroid hormone regulation.
Heme iron
A form of dietary iron found in animal products such as meat and poultry. Heme iron is generally absorbed more efficiently by the body than non-heme iron from plant sources.
Tolerable Upper Intake Level (UL)
The highest daily intake of a nutrient that is unlikely to cause adverse health effects in most people. Established by the USDA and NIH to guide safe supplementation and consumption limits.
Phytate
A naturally occurring compound in plant foods such as grains, legumes, and seeds that can bind to minerals like zinc and iron, reducing how much the body absorbs.
Iodized salt
Table salt that has been fortified with iodine, a public health measure introduced in the U.S. in the 1920s to prevent iodine deficiency and associated thyroid disorders.
This article is for general informational and educational purposes only and is not a substitute for professional medical or dietary advice. If you have concerns about your mineral intake or nutritional status, consult a qualified healthcare provider or registered dietitian.
