You may think vitamin and mineral deficiencies are a thing of the past, experienced only by sailors on long sea voyages. But even today, it’s possible to lack some of the essential nutrients your body needs to function optimally.

“Nutrient deficiencies alter bodily functions and processes at the most basic cellular level,” says Tricia L. Psota, PhD, RDN, a partner at Nutrition On Demand who is based in Quakertown, Pennsylvania. “These processes include water balance, enzyme function, nerve signaling, digestion, and metabolism. Resolving these deficiencies is important for optimal growth, development, and function.”

Nutrient deficiencies can also lead to diseases. “For example, calcium and vitamin D deficiencies can cause osteopenia or osteoporosis, two conditions marked by brittle bones,” says Kate Patton, RD, a dietitian at the Cleveland Clinic in Ohio. “And inadequate iron can cause anemia, which zaps your energy.”

Telltale symptoms are usually the first clue that you are low in one or more important vitamins or minerals, says Patton. Here’s how to recognize seven common nutrient deficiencies.

1. Calcium: Numb, Tingling Fingers and Abnormal Heart Rhythm

Calcium is important for maintaining strong bones and controlling muscle and nerve function, according to the National Institutes of Health (NIH). Signs of severely low calcium include numb, tingling fingers and abnormal heart rhythms, says the Cleveland Clinic. That said, there are no short-term, obvious symptoms of calcium deficiency.

Most adults need 1,000 milligrams (mg) of calcium each day, though women over 50 and men over 70 need 1,200 mg, per the Mayo Clinic. Patton says you’ll likely get enough from at least three servings of milk or yogurt a day. Cheese is another good source of calcium, but if you’re not big on dairy, you can find this nutrient in calcium-fortified plant-based milks or breakfast cereal (check the nutrition facts label of the food to see if calcium has been added), and dark leafy greens like kale and broccoli, according to the NIH.

2. Vitamin D: Fatigue, Bone Pain, Mood Shifts, and More

This vitamin is another that’s crucial for bone health and may also prevent some cancers, according to the Cleveland Clinic. Symptoms of a vitamin D deficiency can be vague — fatigue, bone pain, mood changes, and muscle aches or weakness may set in.

“If it goes on long term, a vitamin D deficiency can lead to softening of the bones,” Dr. Psota says. Long-lasting deficiency also may be linked with cancers and autoimmune diseases, says Michelle Zive, PhD, a nutrition coach based in San Diego.

According to the NIH, most adults need 15 micrograms (mcg) of vitamin D each day, and adults older than 70 need 20 mcg. Patton suggests having three servings of fortified milk or yogurt daily and eating fatty fish, such as salmon or tuna, twice a week, as these are foods that contain vitamin D. Spend some time outside in the sunshine every day, too, as this is a great source of the nutrient. Ten to 30 minutes a few times a week of direct sunlight exposure should help, Dr. Zive says. But the NIH also notes that it can be hard to get your vitamin D needs solely from food and time in the sun, and so a supplement is often the best way to meet daily requirements for many people.

3. Potassium: Muscle Weakness, Constipation, Irregular Heart Rhythm, and More

Potassium helps your heart, nerves, and muscles work properly and also delivers nutrients to cells while removing waste, according to MedlinePlus. Plus, it’s a useful nutrient that helps offset sodium’s negative impact on your blood pressure: “It’s important in maintaining a healthy blood pressure,” Zive says.

You could become low in potassium in the short term because of diarrhea or vomiting; excessive sweating; antibiotics, laxatives, or diuretics; excessive alcohol consumption; or because of a chronic condition like kidney disease, per the Mayo Clinic. Symptoms of a deficiency include muscle weakness, twitches, or cramps; constipation; tingling and numbness; and an abnormal heart rhythm or palpitations, says MedlinePlus.

For natural potassium sources, try bananas, milk, acorn squash, lentils, and kidney beans and other legumes. Adult men need 3,400 mg each day, and women need 2,600 mg, according to the NIH.

4. Iron: Fatigue, Shortness of Breath, Cold Hands and Feet, Brittle Nails, and More

Iron is necessary to produce red blood cells, which carry oxygen throughout the body, according to UCSF Health. When iron levels get too low, there may be a deficiency in red blood cells, resulting in a condition called anemia. Some groups at increased risk of iron deficiency include menstruating women, growing individuals (such as children and pregnant women), and those following a vegan or vegetarian diet, Zive says.

Anemia can leave you with symptoms including weakness and fatigue, shortness of breath, a fast heartbeat, pale skin, headache, cold hands and feet, a sore or swollen tongue, brittle nails, and cravings for strange things like dirt, according to the Mayo Clinic. The symptoms may be so mild at first that you don’t notice something’s wrong, but as iron stores become more depleted, they will become more intense.

To boost iron levels, Patton recommends eating iron-fortified cereal, beef, oysters, beans (especially lima, navy, and kidney beans), lentils, and spinach. Adult men and women over 50 need 8 mg per day, and adult women younger than 50 need 18 mg each day, according to the NIH.

5. Vitamin B12: Numbness, Fatigue, Swollen Tongue, and More

Vitamin B12 aids the production of red blood cells and DNA, and also improves neurotransmitter function, according to the NIH. Vegetarians and vegans may be at particular risk for vitamin B12 deficiency because plants don’t make the nutrient, and people who’ve had weight loss surgery may also lack B12 because the procedure makes it difficult for the body to extract the nutrient from food, according to Harvard Health Publishing.

Symptoms of severe B12 deficiency include numbness in the legs, hands, or feet; problems with walking and balance; anemia; fatigue; weakness; a swollen, inflamed tongue; memory loss and difficulty thinking, per Harvard. These symptoms can come on quickly or gradually, and since there’s such a wide range of symptoms, you may not notice them for a while.

Adults need 2.4 mcg of B12 per day, according to the NIH. It’s most commonly found in animal products, and Patton recommends fish, chicken, milk, and yogurt to boost your B12 levels. If you’re vegan or vegetarian, Zive suggests opting for foods fortified with B12, such as plant-based milk and breakfast cereals. You can also find B12 in most multivitamins, notes the NIH, but if you’re at risk of being deficient, you can take a supplement specifically containing B12.

6. Folate: Fatigue, Diarrhea, Smooth Tongue, and More

Folate, or folic acid, is a B vitamin that’s particularly important for women of childbearing age, which is why prenatal vitamins usually contain a hefty dose. According to the Mayo Clinic, folate supports healthy growth and function and can reduce the risk of birth defects, particularly those involving the neural tube (the brain and spine). Psota points out that a folate deficiency can decrease the total number of cells and large red blood cells and cause neural tube defects in an unborn child.

Symptoms of a folate deficiency include fatigue, irritability, diarrhea, poor growth, and a smooth, tender-feeling tongue, per MedlinePlus.

Women who could become pregnant should make sure they get 400 mcg of folic acid daily in addition to consuming food containing folate, according to the Centers for Disease Control and Prevention (CDC). Interestingly, folate is best absorbed by the body in supplement form, with 85 percent absorbed from supplements and 50 percent from food, according to the Harvard T.H. Chan School of Public Health.

To get folate from food, go for fortified cereals, beans, peanuts, sunflower seeds, whole grains, eggs, and dark leafy greens.

7. Magnesium: Loss of Appetite, Nausea, Fatigue, and More

Magnesium helps support bone health and assists in energy production, and adults need between 310 and 420 mg, depending on sex and age, according to the NIH. Although deficiency is fairly uncommon in otherwise healthy people, certain medications (including some antibiotics and diuretics) and health conditions (such as type 2 diabetes and Crohn’s disease) can limit the absorption of magnesium or increase the loss of this nutrient from the body.

Magnesium deficiency can cause loss of appetite, nausea and vomiting, fatigue, and weakness, according to the Cleveland Clinic. In more severe cases, it may also lead to numbness and tingling, muscle cramps or contractions, seizures, irregular heart rhythms, personality changes, or coronary spasms.

To help your levels return to normal, eat more magnesium-rich foods, such as almonds, cashews, peanuts, spinach, black beans, and edamame, Patton says.

From Nutrient Deficiency to Healthy Eating

If you suspect you have a nutrient deficiency, talk to your doctor. “Blood tests can help determine if you are deficient,” Patton says. And if you are, your doctor can refer you to a registered dietitian or recommend supplements.

The best way to avoid or remedy nutrient deficiencies is to make sure you are eating a balanced, nutrient-rich diet, Patton says. “I encourage food first, but if you are at an increased risk of a nutrient deficiency, you may benefit from taking a multivitamin,” she says.

Zive says that those at risk include the elderly, pregnant women, and individuals with either restrictive diets (such as vegans and vegetarians) or limited diets that lack fruits and vegetables (typical of the standard American diet). Make sure to check with your doctor if you have questions about your risk.

Editorial Sources and Fact-Checking

Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.