Key takeaways

Nutrient deficiencies can be prevented and treated with dietary changes, supplements, and healthcare guidance.
Common deficiencies in the United States include calcium, essential fatty acids, folic acid, iron, magnesium, potassium, and vitamins A, B12, C, and D, all vital for health.
Preventing deficiencies requires a balanced diet with fruits, vegetables, and proteins, plus regular check-ups to detect and address any issues early.

In this article:

Nutrient deficiency 101
Common deficiencies
How to prevent deficiencies
The bottom line

In this article

Nutrient deficiency 101
Common deficiencies
How to prevent deficiencies
The bottom line

Although most of us are aware of the benefits of eating a balanced diet, many people in the United States have nutrient deficiencies. In fact, more than 40% of Americans are deficient in vitamin D, 7% are deficient in vitamin C, and nearly 13% are deficient in vitamin B6. Failing to get key nutrients can lead to a variety of health problems, including fatigue, night blindness, osteoporosis, high blood pressure, thyroid issues, and even acne.

If you’re experiencing any of the above symptoms and have ruled out other health conditions, you may have a nutrient deficiency. Detecting and preventing the most common ones—including calcium, essential fatty acids, folic acid, iron, magnesium, potassium, and vitamins A, B6, B12, C, and D—can be achieved through monitoring and adjusting your diet, considering dietary supplements and having a conversation with your healthcare provider if you suspect you have a vitamin or mineral deficiency.

What is a nutrient deficiency, and how do I know if I have one?

“A nutrient deficiency occurs when a body doesn’t get the necessary amount of nutrients it needs (a nutrient being a substance that is essential for growth, development, or the maintenance of life),” says Michael Jay Nusbaum, MD, the Medical and Surgical Director at Nusbaum Medical Centers in New Jersey.

Many people have vitamin deficiencies but never realize it. Those who don’t eat enough, or eat poor-quality food are at the highest risk. In some cases, symptoms may lead to a patient getting testing that reveals the deficiency.

Once a nutritional deficiency is detected, it’s treated by providing the nutrients needed in the diet through food, supplements, or both. In severe cases, according to Dr. Nusbaum, IV infusions may be necessary to replenish vitamin or mineral levels.

11 common nutrient deficiencies

In the United States, calcium, essential fatty acids, folic acid, iron, magnesium, potassium, and vitamins A, B12, C, and D are some of the most common nutrient deficiencies.

1. Calcium

Calcium is known as an important building block for strong bones. But the essential mineral is also key for nerve and muscle function and heart health. Because calcium is stored in the bones and withdrawn when we don’t consume enough, a calcium deficiency leaves bones weak and more likely to break.

Nearly 70% of Americans fail to meet the recommended daily intake of calcium. Most commonly, calcium deficiency is due to inadequate intake of calcium-rich foods. Additionally, caffeinated beverages, alcohol, soda, dark leafy greens, beans, and whole grains can decrease the body’s ability to absorb calcium from the food we eat. Signs of a calcium deficiency can include mottled teeth, weak fingernails, muscle cramps, or numbness in the fingers.

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2. Essential fatty acids

Essential fatty acids such as omega-3 and omega-6 are important for overall health. Omega-3 fatty acids are found in fatty fish, nuts, and flaxseed. “Deficiencies occur when omega-3 consumption is too low, but symptoms can also appear if omega-6 fatty acid intake from processed foods is too high,” says Paul Kriegler, RD, the nutritional products program manager at Life Time. Omega-6 fatty acids are also important for overall health, but they can cause problems if you take in more omega-6 than omega-3 foods. Because omega-6 fatty acids are found in vegetable oils and grains, many Americans take in too much omega-6. A good rule of thumb is to eat 2-4 times as many omega-3 foods as omega-6 foods. Symptoms of fatty acid deficiency can include scaly skin, brittle or cracking nails, and acne.

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3. Folic acid

Folic acid (a synthetic form of vitamin B9), plays a role in maintaining healthy red blood cells and is particularly important during pregnancy. Women with low folic acid stores have a greater chance of having a baby with congenital issues that affect the brain and spinal cord. Outside of pregnancy, folic acid helps prevent anemia.

Those who don’t consume enough fruits and vegetables (or who overcook their veggies) are at the greatest risk of developing a folate deficiency. People who consume high amounts of alcohol or who take certain medications (such as phenytoin, methotrexate, sulfasalazine, triamterene, trimethoprim-sulfamethoxazole, and barbiturates) also have an increased risk of developing a folic acid deficiency. Symptoms may be similar to those caused by an iron deficiency, including fatigue, lethargy, hair loss, and shortness of breath.

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4. Iron

“Iron deficiency can occur for multiple reasons: inadequate consumption of iron-rich foods, poor iron absorption, or iron loss through excess blood loss. Iron deficiency may also be more common during certain stages in life, such as adolescence, pregnancy, or breastfeeding,” Kriegler says. Other risk factors for iron deficiency include certain stomach or intestinal conditions that either cause bleeding or reduce the absorption of iron from food.

Iron deficiency anemia can cause general fatigue, headaches, dizziness, shortness of breath, muscle weakness, pale skin color, high heart rate, and chest pain. Iron levels should be routinely checked in pregnant women, as expectant mothers are at an increased risk of developing this condition.

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RELATED: Iron-rich foods

5. Magnesium

Magnesium is an essential mineral that is crucial to hundreds of metabolic reactions within the body, including regulating muscle and nerve function. “Many Americans don’t consistently consume adequate amounts of magnesium, and most multivitamin supplements contain insufficient amounts of magnesium because it’s a bulky mineral that takes up a large volume of space in the formula. Therefore, it’s often recommended as an additional, stand-alone supplement,” Kriegler notes. Symptoms of a magnesium deficiency include muscle cramps, abnormal heart rhythms, unexplained numbness or tingling, and high blood pressure.

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6. Vitamin A

Vitamin A is essential in the replacement of skin cells and for maintaining optimal vision and a healthy immune system. For this reason, those with a vitamin A deficiency are at an increased risk of acquiring a severe infection. As young children may be more prone to infections, it’s crucial that those under the age of 5 get enough vitamin A in their diets or through supplements. In adults, one of the key warning signs of a vitamin A deficiency is night blindness.

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7. Vitamin B12

One of the eight B vitamins, vitamin B12 helps to form red blood cells, enhances neurological function, and provides building blocks for DNA. Those most at risk for a vitamin B12 deficiency are vegans, people with intestinal problems that limit vitamin absorption, older adults, and those taking long-term heartburn medications. Symptoms of vitamin B12 deficiency are similar to those of anemia, including weakness, pale skin, and shortness of breath. If left untreated, B12 deficiency can also cause numbness, tingling, mood changes, and even cognitive trouble.

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8. Vitamin C

Vitamin C acts as an antioxidant within the body, helping to prevent cell damage inflicted by free radicals. It also helps in the absorption of iron and the production of hormones and amino acids. The most commonly known effect of a vitamin C deficiency is scurvy, a disease that causes inflamed and bleeding gums, easy bruising, weakness, fatigue, rashes, and difficulty healing wounds. While scurvy is uncommon today, if left untreated, it can be fatal. Proper vitamin C intake is crucial to support the production of collagen, a protein that is necessary for the repair of skin, cartilage, bone, and teeth.

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9. Vitamin D

Vitamin D is unique in that most can be produced by our bodies when exposed to adequate amounts of sunlight. Vitamin D’s key role is to regulate calcium absorption. Those with a vitamin D deficiency are unable to absorb that calcium and, in turn, maintain healthy bones. However, vitamin D has several other important roles for overall health, including supporting cardiovascular health, testosterone, and immune function.

Getting 10–15 minutes of mid-day sun exposure on the face, hands, and arms without protective sunscreen is usually enough to maintain healthy vitamin D levels, depending on the time of year, latitude, and skin pigmentation characteristics. Remember, if your skin is starting to turn pink, you’ve gotten too much sun.

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10. Potassium

Potassium deficiency (hypokalemia) affects around 11% of individuals in the United States. It can occur due to inadequate dietary intake, medications, and alcohol intake. Medical conditions like chronic kidney disease or gastrointestinal disorders can also lead to problems with potassium levels. If you have a potassium deficiency, you may experience symptoms like muscle weakness, fatigue, and digestive issues. It is important to know that if potassium levels are too low or too high, life-threatening heart rhythms can occur.

Diagnosis usually involves blood tests to measure potassium levels. To boost potassium intake, eat potassium-rich foods, such as bananas, oranges, potatoes, spinach, and beans. It is important for people with kidney disease to know that they should not start potassium supplementation without discussing it with their healthcare provider.

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11. Vitamin B6

Vitamin B6 is a very important vitamin that your body needs to support the production of red blood cells, cellular metabolism, the immune system, and brain health. Symptoms of B6 deficiency can include fatigue due to anemia, sores in the mouth, tingling in the hands and feet as well mood changes. In severe cases, deficiency can cause seizures. This very important vitamin is found in meat, fish, nuts, beans, grains, fruits, and vegetables. People with celiac or inflammatory bowel disease and those who drink excessive amounts of alcohol are at high risk for developing this deficiency.

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How to prevent nutrient deficiencies

“The simplest way to prevent nutrient deficiencies is to eat a wholesome, nutrient-dense diet based on an abundance of produce (seven-plus servings per day) and ample protein, plus supplementing your diet every day with a high-quality multivitamin, vitamin D, and omega-3 fish oil,” Kriegler says. If you’re concerned about a nutrient deficiency, there are a few steps you can take.

Get tested

If you’re exhibiting symptoms of a deficiency, your healthcare provider can order blood tests to evaluate your essential nutrient levels. An individual blood test can be conducted to assess a specific nutrient deficiency or malnutrition. Overnight fasting may be recommended to enhance the accuracy of results.

Evaluate your diet

Getting nutrients from your diet while avoiding processed foods, fast foods, and sugars is the ideal way to avoid a nutrient deficiency. Food sources include:

Calcium: Dairy products (cow’s milk, yogurt, or cheese), sardines, calcium-fortified orange juice, and dark green leafy vegetables
Folic acid: Eggs, leafy green vegetables, fruits, and dried beans and peas
Essential fatty acids: Cold water fish, flaxseed, and olive oil
Iron: Fortified dairy products, fatty fish, egg yolks, red meat, poultry, fish, and beans or legumes
Magnesium: Pumpkin seeds, leafy green vegetables, beans, legumes, and whole grains
Vitamin A: Spinach, chard, sweet potatoes, squash, pumpkins, carrots, mangoes, papayas, eggs, and milk
Vitamin B12: Animal products such as meat, fish, poultry, eggs, and dairy products
Vitamin C: Citrus fruits, broccoli, cantaloupe, cauliflower, kiwi, sweet potatoes, tomatoes, kale, bell peppers, and strawberries
Vitamin D: Fatty fish, beef liver, egg yolks, or a number of fortified foods, such as cereals (however, it’s almost impossible to achieve optimal vitamin D levels solely through diet, according to Kriegler)

Consider supplements

Even with a healthy diet, it can be difficult to achieve an optimal balance of nutrient intake. Supplements containing essential nutrients are available either alone or in multivitamin formulas. Your healthcare provider or pharmacist can help you determine the right balance of supplements.

Stay hydrated

Adequate hydration is essential for nutrient absorption, which is necessary for preventing nutrient deficiencies. Water dissolves vitamins and minerals for absorption, supports digestive juices for better nutrient uptake, and assists with metabolic processes. Proper hydration aids kidney function in filtering waste and retaining nutrients, maintains optimal cell function for nutrient absorption, and helps prevent constipation, which is vital for efficient digestion. Overall, hydration is key in supporting functions critical for nutrient utilization.

Lifestyle factors

Lifestyle factors that influence nutrient absorption and gut health include a balanced diet rich in whole foods and regular physical activity. Sufficient sleep (seven to nine hours each night) is important, too, as it supports nutrient utilization. Stress management is essential, as chronic stress can hinder digestion. Limiting alcohol and avoiding tobacco also improve gut health, enhancing nutrient absorption and overall health.

The bottom line

Many Americans have nutrient deficiencies. To avoid deficiencies and enhance nutrient absorption, eat a balanced diet rich in whole foods, stay hydrated, exercise, and limit alcohol consumption. Consult a healthcare provider for testing and advice if you experience symptoms like fatigue or weakness.