Overview

Minerals fall into two broad categories: major minerals (calcium, magnesium, potassium, sodium, phosphorus), needed in gram amounts, and trace minerals (iron, zinc, selenium, iodine, copper, manganese), needed in milligram or microgram amounts. Both deficiency and excess can cause clinically significant problems, and the safe range between adequate and excessive intake is narrower for some minerals — such as selenium and iodine — than others.

Major mineral deficiency signs

Calcium — muscle cramps and, over the long term, reduced bone density
Magnesium — tremor, muscle cramps, irregular heart rhythm, fatigue
Potassium — muscle weakness, fatigue, irregular heart rhythm
Sodium — rare from diet alone; confusion and, in severe cases, seizures

Trace mineral deficiency signs

Iron — fatigue, pale skin, shortness of breath (iron-deficiency anemia)
Zinc — impaired wound healing, hair loss, reduced immune function, altered taste
Iodine — goiter, hypothyroidism
Selenium — rare in most parts of the world; associated with a specific cardiomyopathy in severely deficient regions

Trace mineral toxicity signs

Iron — in hereditary hemochromatosis or supplement overdose, organ damage to the liver and heart; acute overdose is a leading cause of pediatric poisoning
Zinc — chronic high-dose supplementation can cause copper deficiency and impaired immune function
Selenium — excess causes hair and nail brittleness, GI distress, and in severe cases neurological symptoms
Iodine — both deficiency and excess can disrupt normal thyroid function

Certain medications increase the risk of mineral depletion: diuretics can deplete potassium and magnesium, proton pump inhibitors can reduce magnesium, calcium, and iron absorption, and long-term metformin use is linked to reduced vitamin B12 (and related micronutrient) status.

Who is at higher risk

Older adults, people with malabsorption conditions, pregnant women, vegetarians and vegans (particularly for iron, zinc, and iodine), athletes with high sweat losses, and people with chronic kidney disease (who must carefully manage potassium and phosphorus intake) are at elevated risk for mineral imbalance.

Sources

NIH Office of Dietary Supplements — Iron, Zinc, Selenium, Iodine, Magnesium, and Potassium Fact Sheets (Health Professional)

Clinically reviewed by Dr. Shilpa Thakur. Last reviewed 2026-07-20. Educational information, not medical advice; discuss any suspected deficiency or toxicity with a qualified clinician.

Mineral Deficiency & Toxicity: Laboratory Values, Clinical Signs & the Complete Diagnostic Reference