Plus, find out how much you need to keep your bones and heart healthy.
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Growing up, you were likely told to "drink your milk" if you want strong bones. That's because milk is a well-known source of calcium, which plays a critical role in bone health. Besides supporting bone development, calcium is needed for healthy teeth, blood clotting, and for your heart, muscles and nerves to function correctly, per the NIH Osteoporosis and Related Bone Diseases National Resource Center. It's no surprise, considering 99% of your body's calcium is found in your bones and teeth. As a result, not getting enough calcium can lead to the development of osteoporosis and significantly increases the risk of bone fractures as you age, per the National Library of Medicine.

If you don't eat enough calcium-rich foods or take supplements, you may be among the 39% of Americans who are deficient in calcium (also called hypocalcemia), per the NIH. "Calcium deficiency is more common in women than men, as their calcium needs are greater. According to the National Institutes of Health, about 1 in every 3 women take dietary calcium supplements while only 1 in 4 men take dietary calcium supplements," says Hayley Miller, M.S., RDN, LD, a registered dietitian at Persona Nutrition.

So how can you tell if you're one of the millions not hitting their daily calcium requirement? Read on to find out how much calcium you need, plus five sneaky signs you might be deficient in this essential mineral.

How Much Calcium Do You Need per Day?

Making sure you get enough calcium is critical for good health. According to the National Library of Medicine, calcium is the most abundant mineral in your body, comprising up to 2% of your total body weight—with the average adult having 1,200 grams of calcium present in their body. Calcium promotes healthy cell functioning, allows blood to clot, supports optimal muscle contraction and regulates metabolism. In addition, calcium is crucial for heart health by helping maintain a regular heart rhythm and maintaining healthy blood pressure, per a 2019 article published in Nutrients.

The amount of calcium you need varies depending on your age and sex. The 2020-2025 Dietary Guidelines for Americans recommends that adults between the ages of 19 and 50 get 1,000 milligrams of calcium daily. Men 51 and older also require 1,000 milligrams, while women ages 51 and up need 1,200 milligrams.

Fortunately, you can get all the calcium you need from food. "The most common dietary calcium sources include dairy products such as milk, yogurt and cheese," says Miller. "Less common (but still great) sources of calcium include plant-based sources like leafy greens such as spinach and kale. Beans, tofu and seeds also provide a good calcium source." Plus, many foods, including nondairy milk and orange juice, are calcium-fortified. If you can't get enough calcium from food, supplements are available. But, always talk to your health care provider before taking any new supplements.

5 Signs You Might Have a Calcium Deficiency

1. Your Bones Are Brittle and Weak

A hallmark sign of calcium deficiency is an overall loss of bone health. If you don't consume enough calcium, your body will leach calcium from your bones and teeth to maintain adequate calcium levels in the blood. Calcium deficiency can cause bone weakness and frailty if left unchecked, dramatically increasing your fracture risk and chances of osteoporosis.

"Not only do bones lose strength as we age, but our bodies also get worse at absorbing the calcium we eat," says Miller. "Fragile bones ... may result in more falls such as up and down the stairs or in and out of the shower. In addition, long-term calcium deficiency in adults can lead to osteoporosis, meaning that your bones are more porous, making them more susceptible to long-term damage and breakage."

2. You're Exhausted All the Time

Lacking healthy amounts of calcium can result in fatigue. But this isn't your run-of-the-mill tiredness—it's a persistent state of low energy and feeling weak, per the National Library of Medicine. Hypocalcemia symptoms tend to be less obvious and more long-term than other nutrient deficiencies.

"As you begin to develop a calcium deficiency, you may not notice that you're losing strength or have difficulty performing everyday tasks, as this can easily be confused for fatigue related to a variety of other factors such as energy levels, sleep quality, physical activity levels or overall nutrition," explains Miller.

Fatigue associated with hypocalcemia is characterized by brain fog, dizziness, lightheadedness, confusion and difficulty focusing. Since your muscle fibers and nerves require calcium, not having enough of this vital mineral depletes cells of their calcium stores, causing exhaustion and lethargy.

3. You Experience Muscle Cramps and Spasms

Telltale signs of calcium deficiency are muscle cramps and muscle spasms. As symptoms worsen over time, muscle cramps become increasingly common (especially in the back of your lower legs), and you may develop stiff, achy muscles. That's because calcium is required to help muscles contract and relax, per a 2018 publication in Best Practice & Research Clinical Endocrinology & Metabolism. When your muscles are deprived of calcium, neurons become unstable and fire spontaneously, which can trigger painful muscle contractions.

4. You Have Poor Oral Health

Lacking calcium could spell trouble for your next dentist visit. Like your bones, calcium helps keep your teeth healthy. Everything you eat and drink produces bacteria in your mouth, which degrades minerals in your teeth. Having sufficient amounts of calcium can help prevent such mineral loss. Without adequate calcium levels, your teeth are depleted of minerals essential for keeping them strong and healthy. What's more concerning is that calcium deficiency can lead to periodontal disease (inflammation of your gums and bones surrounding your teeth), which has been linked to cancer, according to a 2019 article published in Dentistry Journal.

5. Your Heart Rhythm Is Off

Calcium plays a significant role in heart health. For example, an irregular heartbeat (arrhythmia) is a common sign of inadequate calcium levels in your blood and is a leading cause of sudden cardiac death, per a 2017 publication in Clinical Medicine Insights: Cardiology. That's because the heart is a muscle and when its cells don't receive enough calcium, they cease to function properly and can cause spasming of the heart muscle, per a 2018 article in Frontiers in Physiology. Furthermore, your blood vessels become constricted when calcium levels are low, resulting in an irregular heart rhythm.

The Bottom Line

Calcium is needed for several vital body functions, from strong bones to heart health. You can avoid deficiency by eating calcium-rich foods or taking a high-quality calcium supplement. Common signs of hypocalcemia include brittle bones, muscle cramps, fatigue, dental issues and irregular heartbeat. If you're concerned about your calcium levels, talk to your health care provider about taking a blood test to check your calcium levels. You can also speak with a registered dietitian about strategies for increasing calcium intake or seeing if supplementation is right for you.

Ultimately, an ounce of prevention is worth a pound of cure when it comes to calcium deficiency. Miller advises, "The best way to prevent a calcium deficiency is to add calcium-rich foods to your diet. To cover your needs, try eating high-calcium foods at every meal. Almond milk, tofu, yogurt, cheese, dark leafy greens and calcium-fortified foods are great sources of calcium."