Calcium, the most abundant mineral in the body, makes up 1.5 percent to 2 percent of your weight. Most of the mineral resides in your bones and teeth, but calcium in your bloodstream plays an important role in many biochemical processes. Calcium deficiency is usually caused by a medical condition, although it’s occasionally caused by not getting enough in your diet. When your blood calcium levels fall too low, a condition called hypocalcemia, your body begins pulling calcium from your bones and teeth, weakening them. If you lack calcium in your diet, you can counter this calcium insufficiency through supplements. This is especially important for women since your need for calcium increases as hormone levels decline with age, making supplementation essential.
How Is Calcium Used in the Body?
Ninety-eight percent of your body’s calcium is in your bones and one percent in the teeth. Your body uses the remaining calcium for another critically important yet less-known role: cell to cell communication. Calcium ions (Ca++) help brain cells release neurotransmitters to the body and help muscle cells contract. The importance of this mineral to your health cannot be overstated.
What Is Calcium Deficiency?
Calcium deficiency, or hypocalcemia, means your body has inadequate levels of calcium in the blood. Calcium insufficiency, on the other hand, only means that you are not getting the recommended daily intake set by health organizations, such as the Food and Nutrition Board (FNB) of the Institute of Medicine in the United States. Calcium deficiency is a more serious condition than insufficiency. Several groups of people are at risk of not getting enough, including the elderly, pre-teens, and teenagers, but also vegans, people who are overweight, and low-income individuals.
Calcium deficiency rarely arises from a mere lack of calcium in the diet. You are much more likely to develop a deficiency from a medical condition that lowers the body’s ability to absorb calcium from foods or supplements.
Some medical conditions that can cause calcium deficiency are:
- Kidney failure
- Surgical stomach or parathyroid gland removal
- Massive blood transfusions
- Septic shock
- Hormonal changes, particularly in women
- Vitamin D deficiency
Several medications increase your risk of developing calcium deficiency, as well.
- Drugs that treat elevated calcium levels
- Anticonvulsant drugs like phenytoin and phenobarbital
- Certain chemotherapy drugs
Calcium Deficiency Symptoms
When your body enters a calcium-deficient state, it can cause other medical conditions, particularly osteopenia and osteoporosis. Osteopenia means low bone mineral density. While osteopenia is not a disease, it can lead to osteoporosis over time. In osteoporosis — which literally means porous bones — bone mineral density becomes even lower than in osteopenia, leading to a higher chance that they will break during normal, daily physical activities. This disease may lead to the hunched back that occurs in some older adults and is a factor in 8.9 million bone fractures worldwide every year. Osteoporosis affects women four times as often as men.
Hypocalcemia or calcium deficiency is a particularly concerning condition because the body will readily pull calcium from the bones in the event of a blood calcium deficiency in orders to support the proper function of the brain, heart, nervous system, skin, and muscles. Calcium insufficiency often has no symptoms, but once you’ve reached the stage of a true calcium deficiency disease, or hypocalcemia, you may have the following symptoms:
- Weak or brittle nails
- Weakened grip strength
- Numbness and tingling in the fingers
- Muscle cramps
- Lethargy and fatigue
- Poor appetite
- Abnormal heart rhythms
- Stooped or hunched posture
Calcium Deficiency & the Cardiovascular System
According to the National Center for Geriatrics and Gerontology, calcium deficiency deteriorates the bones as well as the cardiovascular system. The Department of Geriatric Medicine at Osaka University Medical School evaluated available research and found it to suggest that calcium deficiency contributes to the development of high blood pressure.
Calcium Deficiency & Brain Health
Links between calcium deficiency and Alzheimer's disease have been observed. If deficient, increasing both calcium and vitamin D intake may lessen some of the risks associated with Alzheimer's disease. Additionally, deficient calcium levels have been observed in adults with anxiety and headache. It’s well known that calcium plays a role in memory and cognition, and changes in calcium may influence how the brain ages.[7, 8] If you want to maintain brain health, ensure you get adequate amounts of calcium and vitamin D.
Groups at Risk of Calcium Deficiency
There are a few specific groups of people who are at a greater risk of calcium deficiency, and as a result, these groups should pay closer attention to their diet and supplement needs.
Post-Menopausal Women & Older Adults
When women go through menopause — when menstruation ceases permanently — estrogen levels reduce, which, in turn, lowers how much calcium gets absorbed into bones. As a result, women can lose three to five percent of their bone mass per year in the first few years after menopause, which typically slows to one percent after that. Eating high-calcium foods, and taking calcium and vitamin D — which increases calcium absorption — can help stem this. Although age-related bone loss is most pronounced in women, all older adults should pay attention to their calcium intake. Importantly, older women are also at greater risk of exceeding the recommended upper limit of calcium intake from both diet and supplements, which has its own risks. Older women should carefully monitor their calcium intake levels.
Amenorrheic Women (without menstruation)
When body fat levels drop too low, women may cease menstruating. This typically happens for two reasons. The first situation occurs in women who are athletes or who engage in extreme exercise. The other situation involves women with eating disorders, particularly anorexia nervosa, in which a person does not consume enough calories. When a woman does not have menstrual cycles because of a lack of body fat, it decreases calcium absorption and increases calcium excretion rates. As a result, women in these groups have a higher chance of getting stress fractures — in other words, broken bones.
Vegans & Vegetarians
People who follow a vegan diet — not eating any animal products — have a higher risk of developing a calcium deficiency primarily because they do not eat dairy. Although vegetarians may eat dairy, they still have a slightly higher risk of calcium deficiency than those who eat both meat and dairy, according to the National Institutes of Health. However, vegetarians may or may not be likely to have either calcium or vitamin D deficiencies than other groups due to the inconsistent intake of dairy — so the jury is out.
Data between 2001 and 2008 for the first time revealed that low-income individuals in the United States have a higher risk of a calcium insufficiency — not getting enough in their diet. These trends held in the 2009–2010 survey, as well. These surveys show that calcium intake increases with income.
Teenagers and pre-teen children ages 9 through 13 and girls ages 14 through 18 may also be at higher risk of calcium insufficiency. Because the skeletons of teenagers are still growing, this age group should ensure that they either supplement their diet or get enough calcium through supplementation.
Overweight and obese individuals are other groups at higher risk of calcium insufficiency. Some studies have linked calcium intake levels to lower body weight; however, dietary supplementation with calcium was not found to actually cause people to lose body weight in clinical studies. A more likely explanation for this relationship between calcium and weight is that overweight individuals have lower calcium intake due to dietary differences compared with non-overweight individuals.
People With Digestive Conditions
Celiac disease is an intestinal ailment that leads to lower nutrient absorption. Deficiencies in calcium and vitamin D are common in adults with celiac disease, and supplementation is often recommended for adults. Inflammatory bowel disease (IBD) is another disorder that affects more than a million Americans. Calcium absorption can be a concern with IBD, sometimes leading to lower bone density. Eating calcium-rich foods and supplementation may help.
How to Counteract Calcium Deficiency
Since specific medical conditions — rather than nutritional lack — usually cause calcium deficiencies, the best way to reduce your risk involves living a healthy lifestyle that promotes a healthy body. A healthy natural lifestyle involves diet, fitness, and even spirituality.
I recommend eating a plant-based diet rich in organic fruits, vegetables, nuts, and seeds. If you choose to eat dairy, choose organic, pasture-raised options. Staying fit and avoiding obesity is another important factor for optimal health. Engage in activities that reduce your stress, exercise regularly, eliminate toxins from your life, engage in cleansing, and look to the root cause of any conditions.
These behaviors will not only improve your bone health and decrease your risk of developing hypocalcemia, but they will also lower your overall risk of other health ailments.
If you are in one of the categories of people who are at greater risk of developing hypocalcemia, stay aware of your intake level and occasionally have your blood calcium levels tested by your healthcare provider. Increase your consumption of calcium-rich foods and take supplements if needed.
If your healthcare provider diagnosed you with hypocalcemia, they may treat you with either hormone supplements — typically with post-menopausal women — or medications that increase calcium absorption in the blood, as well as vitamin D and calcium. Become educated about the side effects of any prescribed medications, and do your research to find the highest quality supplements.
Recommended Calcium Intake
The Food and Nutrition Board at the Institute of Medicine established recommended daily allowances (RDA) for calcium as follows:
|0 – 6 months*||200 mg||200 mg||N/A||N/A|
|7 – 12 months*||260 mg||260 mg||N/A||N/A|
|1 – 3 years||700 mg||700 mg||N/A||N/A|
|4 – 8 years||1,000 mg||1,000 mg||N/A||N/A|
|9 – 13 years||1,300 mg||1,300 mg||N/A||N/A|
|14 – 18 years||1,300 mg||1,300 mg||1,300 mg||1,300 mg|
|19 – 50 years||1,000 mg||1,000 mg||1,000 mg||1,000 mg|
|51 – 70 years||1,000 mg||1,200 mg||N/A||N/A|
|71+ years||1,200 mg||1,200 mg||N/A||N/A|
Foods High in Calcium
When you think of calcium-rich foods, you probably think of dairy, but you might be surprised to know that many vegetables are also in this category. The table below lists foods high in calcium that can help you increase your dietary intake of calcium. While spinach has high calcium, its bioavailability is poor, meaning the body does not absorb calcium from it very efficiently. Interestingly, the calcium in kale and other leafy greens is absorbed much more efficiently than spinach in the body — even more efficiently than from milk.
|Food||Mg Per Serving||% Daily Value (For an Adult)|
|Plain Yogurt (8 oz)||415 mg||42|
|Cheddar cheese (1.5 oz)||307 mg||31|
|Milk (2%)||293 mg||29|
|Firm Tofu (fortified)||253 mg||25|
|Salmon (3 oz canned)||181 mg||18|
|Chia seeds (⅛ cup)||130 mg||13|
|Turnip greens (½ cup)||99 mg||10|
|Kale, cooked (1 cup)||94 mg||9|
|Sesame seeds (1 tbsp)||88 mg||9|
|Orange (1 whole)||28 mg||3|
|Kale, raw (1 cup)||24 mg||2|
If your diet lacks calcium, or if you are in one of the other groups at higher risk of developing a calcium deficiency, taking a calcium supplement can provide the calcium you need. Check with your healthcare provider if you have questions about your risk or the amount of calcium you should take.
Types of Supplements
- Calcium orotate
- Calcium carbonate
- Calcium citrate
Calcium comes in a variety of supplemental forms. The most commonly sold supplements are calcium carbonate and calcium citrate, but calcium orotate has the highest bioavailability. Calcium carbonate, which is little different from chalk, has the lowest absorption of all the calcium supplements and must be taken with food because stomach acid must work to help release the calcium from it in this form. Calcium citrate is better absorbed than calcium carbonate, but research by German physician Hans Nieper found that calcium orotate crosses the cell membrane, enabling the highest bioavailability of any other supplement.
Calcium Side Effects & Safety Precautions
Taking too much calcium has health risks. Studies have linked excess calcium supplementation with cardiovascular issues, although scientists believe this may be due to low absorption of certain types of supplements. Because calcium can interfere with how your body absorbs minerals from food, particularly iron, zinc, and magnesium, you should take your supplement in between meals. This is yet another reason why calcium carbonate is a poor choice compared to calcium orotate or citrate, which the body absorbs well on an empty stomach.
These are the upper intake levels that you should take daily for calcium accord to the Food and Nutrition Board.Table 3: Tolerable Upper Intake Levels (ULs) for Calcium
|0 – 6 months||1,000 mg||1,000 mg||N/A||N/A|
|7 – 12 months||1,500 mg||1,500 mg||N/A||N/A|
|1 – 8 years||2,500 mg||2,500 mg||N/A||N/A|
|9 – 18 years||3,000 mg||3,000 mg||3,000||3,000|
|19 – 50 years||2,500 mg||2,500 mg||2,500||2,500|
|51+ years||2,000 mg||2,000 mg||N/A||N/A|
Vitamin D & Calcium
The body requires vitamin D to absorb calcium. Sometimes called the sunshine vitamin, vitamin D helps the body create the hormone calcitriol, which enables the body to absorb calcium. Clearly, if you need supplemental calcium, you should also take vitamin D. While you can get D from the sun, more than half the world’s population is at risk of vitamin D deficiency, and this figure is rising. Extreme deficiency of vitamin D and calcium leads to a bone disease called rickets, which is rare today in the developed world but still prevalent in many countries.
Magnesium & Calcium
Most people have heard that the body needs vitamin D to absorb calcium, but fewer know that you also need magnesium. Magnesium keeps calcium dissolved in the blood, rather than leading to calcifications, such as kidney stones or arthritic pain. Magnesium plays a critical role in maintaining heart health, normal blood pressure, and for promoting a relaxed mood. Magnesium deficiency can cause your body not to absorb vitamin D, which is also necessary for calcium absorption, so ensuring you have adequate intake levels of all three substances is essential for strong bone, brain, and nerve health. Magnesium orotate is the most highly bioavailable magnesium supplement.
Best Calcium Supplement Options
Vitamin D plays a critical role in calcium absorption in the body, so it’s important you get enough of both nutrients. I recommend calcium orotate for the best absorption and bioavailability. Intracal™ provides a plant-based source of calcium orotate that is GMO-free, vegan, and gluten-free; it includes 90 mg of elemental calcium and also 45 mg of elemental magnesium for the recommended 2:1 ratio of these elements. If you want to ensure you get enough vitamin D to improve your body’s absorption of calcium, I recommend Suntrex D3™, our vegan, GMO-free, certified-organic liquid formulation with 2000 IU of lichen-derived vitamin D in every serving.
Do you take calcium supplements? Share your stories in the comments below!
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†Results may vary. Information and statements made are for education purposes and are not intended to replace the advice of your doctor. If you have a severe medical condition or health concern, see your physician.