Dietitian Blog, Health/Wellness, MNT Guidelines, Patient Blog | Mar 28 2022

Understanding common mineral deficiencies

Vitamin and mineral supplements with healthy foods in the background

A healthy diet incorporating a variety of different foods is important to meet the body’s needs, not only for macronutrients but also micronutrients. Like vitamins, the body relies on foods consumed to provide these essential nutrients.

In the typical American diet, iron, potassium, magnesium, and calcium are considered four of the most under consumed nutrients, although they are available in an abundance of food sources. Read on for a refresher of current recommendations and to better understand who is at risk for mineral deficiencies.


Iron1-3 is needed as a co-factor for oxygenated blood and helps support muscles and connective tissues in the body. There are two different forms of iron—heme (from animal sources) and nonheme (from plant-based sources or supplements). Deficiency of iron is most common in the United States with children, young women and during pregnancy.

Recommended dietary allowance (RDA): 

  • Men (19+ years): 8 mg
  • Women (19 to 50 years): 18 mg
  • Women (51+ years): 8 mg   

*Increased RDA with pregnancy, lactation, and vegetarians

Causes of deficiency: Inadequate dietary/supplement intake, gastrointestinal (GI) conditions causing malabsorption, blood loss

Clinical signs of deficiency: anemia, fatigue, weakness, shortness of breath

Food sources: Seafood, meat, nuts, lentils, spinach, tofu, fortified cereal


Potassium2,4 balance is essential within the body for routine function of the heart, cells and nerves.  Mineral needs can usually be met with diet alone, but in some cases, supplements may be recommended. Despite the health benefits of a diet rich in potassium for most individuals, oral intake is below the suggested adequate intake for many adults and children.

Adequate intake: Adults (19+ years): 2,600 to 3,400 mg    

*Needs may vary depending on individual comorbidities

Causes of deficiency: Increased fluid loss (diarrhea, vomiting), inflammatory bowel disease, certain medications, refeeding syndrome, dialysis with kidney disease

Clinical signs of deficiency: weakness, cardiac arrhythmias, mood or mental status changes, nausea and vomiting

Food sources: Milk, tomatoes, bananas, orange juice, potatoes, squash, apricots, lentils, meat, whole grains


Magnesium2,5 intake within the standard American diet is often below the RDA even with availability through a wide variety of food, supplements and medication. Needed for over 300 different enzyme actions in the body, magnesium levels need to be maintained to support optimal health. In general, those most at risk for a magnesium deficiency are older adults and those with Type 2 diabetes, conditions with malabsorption, or with chronic alcohol intake.


  • Adults (19 to 30 years): 310 to 400 mg
  • Adults (31+ years): 320 to 420 mg   

Causes of deficiency: Poor oral intake, GI conditions with malabsorption, alcoholism

Clinical signs of deficiency: nausea, vomiting, fatigue, appetite loss, muscle cramps, changes in mental status

Food sources: Nuts, seeds, whole grains, leafy green vegetables, soy milk, fortified cereal, black beans


Calcium2,6,7 is most well-known for supporting bone health but is also used in the body for muscles, nerves and blood vessels. The body absorbs calcium based on need to support these roles with sources coming from food eaten or supplements. Intake of this mineral is routinely lower than the RDA, particularly in young children.


  • Adults (19 to 50 years): 1,000 mg
  • Men (51 to 70 years): 1,000 mg
  • Women (51 to 70 years): 1,200 mg
  • Adults (71+ years): 1,200 mg        

*Needs may vary depending on individual comorbidities

Causes of deficiency: Poor dietary intake, certain medications, dairy intolerance, hormones, genetics, low vitamin D

Clinical signs of deficiency: weak bones, confusion, brittle nails, muscle cramps and spasms

Food sources: Dairy products (milk, yogurt, cheese), leafy green vegetables, sardines, canned salmon, soy, fortified cereal or juice

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National Institutes of Health Office of Dietary Supplements. Iron: Fact Sheet for Health Professionals. Available at: Accessed February 3, 2022.
Modarski B. Pocket Guide Nutrition Focused Physical Exam Third Edition. Academy of Nutrition and Dietetics;2021.
Mayo Clinic. Drugs and Supplements: Iron Supplement (Oral Route, Parenteral Route). Available at: Accessed February 3, 2022.
National Institutes of Health Office of Dietary Supplements. Potassium: Fact Sheet for Health Professionals. Available at: Accessed February 2, 2022.
National Institutes of Health Office of Dietary Supplements. Magnesium: Fact Sheet for Health Professionals. Available at: Accessed February 4, 2022.
National Institutes of Health Office of Dietary Supplements. Calcium: Fact Sheet for Health Professionals. Available at: Accessed February 4, 2022.
Mayo Clinic. Calcium and Calcium Supplements: Achieving the Right Balance. Available at: Accessed February 4, 2022.
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About Stacey Phillips

Stacey Phillips, MS, RD is a clinical dietitian working with general medicine, oncology, CKD, renal transplant recipients and living kidney donor patients. Outside of her work, Stacey is passionate about improving the resources available to individuals with chronic kidney disease and actively participates on several renal dietitian committees.

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