What Are the Most Common Nutrient Deficiencies?

About one in nine people in the world do not have enough food for proper nutrition. Although malnutrition associated with severe, multiple nutrient deficiencies are a major health concern in developing countries, many Americans and people living in Western world are affected by nutrient deficiencies, too.

There are many reasons why nutrient deficiencies develop, including low intake of nutrients from foods, the quality of food, medical conditions that impair the absorption of the food, and lifestyle habits like drinking alcohol or prescription medications. Some of the most common nutrient deficiencies in the US are iron, vitamin D, vitamin B12, and magnesium deficiency.

Iron deficiency anemia

Iron deficiency is considered the most common known form of nutritional deficiency.

It is more common among young children and women of childbearing age- especially in pregnant women. Those who eliminate animal products from the diet are at risk for iron, B12 and other nutrient deficiencies. Athletes are also at risk to lose iron through the digestive tract or from breakdown of the red blood cells.

Iron deficiency anemia affects more than 1.2 billion people worldwide, including millions of Americans.

Anemia is defined as a deficiency of red blood cells in your blood, which causes pallor and weakness, among other symptoms .

There are many risk factors to develop a deficiency in this nutrient including blood loss from heavy menses, traumas and injuries, diseases that cause bleeding in the digestive or urinary tract. Kidney disease, heart failure and excess weight can interfere with the body’s ability to use and regulate iron metabolism as well.

Left untreated, iron deficiency anemia can cause significant complications including headaches, fatigue, heart problems, complications during pregnancy and developmental delays in children.

A simple blood test evaluating the levels of iron and ferritin confirms the diagnosis. Mild cases are treated with iron pills and adding more iron-rich foods to the diet. Intravenous iron, blood transfusions, erythropoiesis stimulating agent and even surgery can be used, depending on the underlying cause of your iron deficiency.

Vitamin D deficiency

Another common nutrient deficiency is vitamin D deficiency.

Also known as “the sunshine vitamin”, vitamin D is produced in the skin when exposed to the ultraviolet B sunrays. Some foods like fatty fish, egg yolk, beef liver and fortified dairy products are also a source of this nutrient.

Vitamin D deficiency used to be defined as vitamin D levels in the blood below 20 nanograms per milliliter (ng/mL) but current research indicates that optimal levels of this nutrient should be between 30 to 70 ng/ml.

The prevalence rate of vitamin D deficiency in the US is 41.6%. Overall, over one billion people worldwide have less-than-optimal vitamin D levels.

Vitamin D is an essential vitamin and also has hormone-like activity. It regulates over 200 genes and is essential for growth and development.

Vitamin D deficiency has been associated with excess weight, diabetes, high blood pressure, depression, fibromyalgia/chronic fatigue syndrome, low bone density and Alzheimer’s disease.

A shortage of this nutrient has been linked with 17 types of cancer including breast, prostate and colon cancers, as well as heart diseases, strokes and autoimmune diseases.

The elderly, individuals with darker skin, those who work indoors, as well as people who avoid the sun are at risk of vitamin deficiency.

The solution is simple: vitamin D supplements are widely available and are very cost effective. Ideally, the dosage should be based on the vitamin D tests, because many adults may need more than the recommended 1000 to 2000 international units (IU) of vitamin D daily.

Vitamin B12 deficiency anemia

Vitamin B12 deficiency causes megaloblastic anemia, a type of anemia characterized by abnormally enlarged red blood cells.

Almost 20% of Americans older than 60 years of age have B12 deficiency. Pregnant women, children, vegetarians and vegans are also at higher risk to have a shortage of this nutrient.

Other risk factors include medical conditions affecting the stomach or the gut, taking certain medications, stomach surgery or drinking excess alcohol.

Symptoms suggesting B12 deficiency include numbness and tingling, mood changes like depression or irritability, problems with smell and taste, vision problems and painful inflammation of the tongue.

Left untreated, vitamin B12 deficiency can cause serious complications, including infections, bleeding, and permanent damage of the brain and nerves. If a pregnant woman has B12 deficiency during the pregnancy, the baby is at risk to develop birth defects and developmental delays.

Two blood tests are used to screen for B12 deficiency anemia: the complete blood count that measures hemoglobin and another test that evaluates B12 levels in the blood. It’s important to note that B12 levels may be normal even if a person has a deficiency.

The treatment involves B12 supplements, blood transfusions in severe cases, and treating the underlying cause of the deficiency.

Magnesium deficiency

Magnesium is one of the most important minerals in the body.

It is involved in more than 300 chemical reactions, playing a key role in muscle, heart, nerve, and bone health.

Unfortunately, the majority of Americans do not consume enough magnesium in their diet.

Magnesium deficiency has been associated with high blood pressure, heart diseases, abnormal cholesterol levels, diabetes and osteoporosis.

Prescription drugs, and diseases that interfere with food absorption can also lead to a shortage of this mineral.

Signs and symptoms of magnesium deficiency include elevated blood pressure, abnormal heart rhythm, muscle pain and cramps, fatigue, migraines and restless leg syndrome.

Blood tests are not reliable to confirm magnesium deficiency because magnesium is mostly found in your cells and in your bones, and only 1% of magnesium is in your blood.

If magnesium deficiency is suspected, you should increase the consumption of magnesium rich foods like whole grains, nuts, legumes, dark leafy vegetables, and take magnesium supplements.


While routine blood tests can detect iron, vitamin B12 and vitamin D deficiency, many people may have a deficiency in other essential nutrients and not be aware of. Some special tests assess the status of other vitamins and minerals, but the accuracy of these has yet to be established. Consult a healthcare professional specializing in nutrition to get an individual diet and supplements based on your needs.

Key takeaways

Nutrient deficiencies affect one in nine people worldwide, including many Americans.

Some of the most common nutrient deficiencies in the US are iron, vitamin D, vitamin B12, and magnesium deficiency.

The deficiencies may be caused by low intake of nutrients from foods, the quality of food, medical conditions, alcohol consumption, or prescription medications.

Some deficiencies can lead to severe complications , affecting the heart, muscles, nerves and kidneys. Pregnant women, the elderly, athletes, vegetarians and vegans are among those who need to watch their nutrient intake.

Treat nutrition deficiencies by altering your diet, taking supplements, and consulting your healthcare provider.


Centers for Disease Control. Recommendations to Prevent and Control Iron Deficiency in the United States.

Forrest, K.Y.Z. (2011). Prevalence and correlates of vitamin D deficiency in US adults. Nut. Res.

National Heart, Lung and Blood Institute. Iron-Deficiency Anemia.

National Heart, Lung and Blood Institute. Vitamin B12–Deficiency Anemia.

National Institutes of Health. Magnesium.

Pawlak, R., Parrot, S.J., Raj, S., Cullam-Dugan, D., Lucas, D. (2013). How prevalent is vitamin B(12) deficiency among vegetarians? Nut. Res.

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