Trace elements
Trace elements are essential minerals needed or present in very small amounts. Iron, zinc, iodine, selenium, copper, manganese, and molybdenum are common examples. The label refers to quantity, not importance: a small requirement can still support indispensable biological functions.
Classification is not completely uniform. Authorities may base the boundary on body concentration, daily requirement, or established nutrition convention, so an element can be grouped differently at the margins. Trace elements should also not be confused with accidental "traces" of a contaminant on a label. In nutrition, the term refers to defined elements with physiological roles.
Those roles differ substantially. Iron is central to oxygen transport, iodine to thyroid hormones, selenium to selenoproteins, copper and manganese to enzymes, and zinc to hundreds of proteins involved in processes such as cell division and immune function. Because the elements are not interchangeable, a product's combined "trace mineral" dose says little without the amount and chemical form of each ingredient.
Requirements vary by element and life stage. The DGE/ÖGE reference-value collection and EFSA's dietary reference value framework provide nutrient-specific guidance rather than one target for the group. Absorption also matters. Phytate-rich diets can lower zinc absorption, for example, while food preparation and meal composition can change bioavailability.
Meat, seafood, dairy, eggs, whole grains, legumes, nuts, seeds, and vegetables contribute different trace elements. A vegan diet can cover many of them when it is planned well, although iodine, iron, zinc, and selenium deserve deliberate attention. Vitamin B12 also requires reliable supplementation in a vegan diet, but it is a vitamin rather than a trace element. Not everyone following the diet needs the same multinutrient dose.
Both deficient and excessive intakes can cause harm, and the useful range may be narrower for some trace elements than for many foods. High zinc intake can interfere with copper status, while excess iodine or selenium can also be problematic. Symptoms alone are often nonspecific. Use supplements to address a defined need and count overlapping fortified foods and products; suspected deficiency, abnormal laboratory results, pregnancy, or medication interactions call for qualified advice rather than self-prescribed megadosing.