Table 1.

Functional characteristics of essential trace elements for the human body.

	Main Existing Position	Symptoms	Function	References
Iron	Whole human body	Iron-deficiency anemia, liver development is blocked	An important component of human hemoglobin, myoglobin, and oxidase, which can solve symptoms such as iron deficiency anemia	[17,18,34]
Copper	Liver, muscles, and bone	Anemia symptoms, osteoporosis	Helps hemoglobin absorb iron and promotes the growth and formation of bone and myelin sheath	[16,35,36]
Zinc	Bone and skeletal muscle	Excessive zinc leads to nausea, vomiting, diarrhea, and fever, and deficiency of zinc affects growth, sexual maturity, and immune defense system	Essential component of a large number of zinc-dependent enzymes that facilitate the synthesis and degradation of lipids, proteins, and nucleic acids, among others	[37,38]
Manganese	Brain, kidney, pancreas, and liver	Deficiency leads to skeletal deformities, and excess causes human dysfunction	Protects the cardiovascular and cerebrovascular systems of the elderly and affects the body’s antiaging ability	[18,39,40,41]