Calcium Does More Than Grow Strong Bones—3 Key Benefits (2024)

Calcium is a mineral that provides structure to the bones and teeth and regulates critical processes such as nerve and muscle function, hormone secretion, blood vessel dilation, and more.

Calcium is found in many foods, such as yogurt, soybeans, leafy greens, and sardines, and most people can maintain optimal calcium status through diet alone. However, calcium supplements may be necessary for some people. They can also benefit health in several ways—for example, improving certain aspects of bone health and premenstrual syndrome (PMS) symptoms.

Calcium makes up around 65% of bone tissue, so maintaining optimal calcium levels is important for skeletal health. Low calcium status can negatively impact the bones and increase the risk for conditions such as low bone mineral density and fractures.

Calcium supplementation has been shown to improve some aspects of bone health, such as low bone mineral density (low levels of calcium and other minerals in the bones). For example, a 2019 study of 1,490 women found that calcium supplement use was associated with less bone mineral density loss in the femur and lumbar spine over 10-12 years.

Calcium supplements have also been shown to protect against bone density loss associated with long-term corticosteroid treatment and reduce fracture risk in postmenopausal women. Some research suggests that taking an average dose of 1,050 milligrams (mg) daily starting after menopause and continuing for 1.5-4 years may reduce fracture rates by about 25%. Calcium may be especially effective for reducing fracture risk when combined with vitamin D.

Study results are mixed, and it’s unclear if calcium supplementation is necessary or effective for improving bone health and protecting against bone mineral density loss and fracture risk. More research is needed.

Can Improve Calcium Status

Though most people can obtain adequate calcium from diet alone, some people struggle to meet their calcium requirements. For example, conditions that affect the digestive system, such as inflammatory bowel disease (IBD), interfere with calcium absorption. Plus, people with IBD are often treated with medications that increase calcium excretion and reduce its absorption, like corticosteroids.

People with low intake of calcium-rich foods, such as those following vegan diets, may need to supplement with calcium to maintain adequate levels.

Premenstrual syndrome (PMS) is a group of symptoms that occur several days to two weeks before someone gets their period and goes away within the first few days of menstruation. PMS symptoms can range from mild to severe and include cramping, abdominal and back pain, breast tenderness, mood swings, and fatigue. PMS affects over 47% of women of reproductive age worldwide.

Research has identified a link between low calcium intake and PMS symptoms. Scientists theorize that changes in calcium concentrations in the body could stimulate connections between nerves and muscles called neuromuscular junctions, which could worsen PMS symptoms like cramping and abdominal pain. Mood swings and irritability have also been associated with low calcium levels.

One 2020 review of 14 studies found that women with PMS had lower calcium levels compared to women without PMS and that calcium supplementation in doses ranging from 500-1,200 mg per day significantly improved the incidence and severity of PMS symptoms like water retention, pain, fatigue, depression, and food cravings.

Increasing calcium intake from foods may also decrease the risk of PMS. Some study findings suggest that taking an average of 1,283 mg of dietary calcium per day may decrease the risk of developing PMS by as much as 30%.

May Protect Against Preeclampsia

Preeclampsia is a dangerous condition that develops during pregnancy characterized by hypertension (high blood pressure) and protein in the urine. Taking calcium supplements during pregnancy may protect against preeclampsia development amongst populations with low calcium intake.

A 2022 review that included 48 studies found that medium and high doses of calcium delivering 1-1.49 grams (g) and ≥1.5g of calcium, respectively, reduced the incidence of pre-eclampsia in healthy pregnant women.

Other studies have shown that calcium supplements can reduce preeclampsia risk in high-risk populations. For this reason, the World Health Organization (WHO) recommends that populations with low dietary calcium intake or at a high risk of developing preeclampsia supplement 1.5-2 g of calcium daily during pregnancy.

Calcium is found in a number of foods. Here are some of the best sources of calcium you can eat:

• Yogurt: 415 milligrams (mg) per 8 ounces (oz), or 32% of your daily value (DV)
• Sardines, canned with bones: 325 mg per 3-oz serving, or 25% DV
• Milk, nonfat: 299 mg per cup, or 23% DV
• Soybeans, cooked: 262 mg per cup, or 20% DV
• Spinach, boiled: 246 mg per cup, or 18% DV
• Salmon, canned with bones: 181 mg per 3-oz serving, or 14% DV

Calcium is also concentrated in other dairy products like cottage cheese, as well as certain seeds and leafy greens.

How To Take Calcium

It’s recommended to split calcium into separate doses as the body can only absorb a small amount at a time. This will help increase absorption.

Do not take more than 500 mg of calcium at a time. For example, if you’re taking 1,000 mg of calcium per day, take 500 mg of calcium in the morning and 500 mg of calcium in the afternoon.

Calcium carbonate, which is more associated with digestive side effects, should be taken between meals. Calcium citrate (a more expensive form) can be taken with or without food.

It’s recommended that adults take 1,000-1,300mg of calcium per day depending on age and sex.These recommendations are for total dietary calcium intake, including the calcium found naturally in food and dietary supplements.

Most multi-nutrient supplements provide 200-300 mg of calcium, while calcium-only supplements typically contain 500-600 mg per dose.

Calcium can interfere with the absorption of other minerals, such as iron, zinc, and magnesium. For this reason, calcium supplements should be taken apart from other mineral supplements whenever possible.

Is Calcium Safe?

When taken in appropriate doses, calcium is considered safe for most people. However, taking high-dose calcium supplements over long periods may increase the risk of several health conditions, including heart disease, kidney stones, high calcium levels, and prostate cancer.

For example, studies suggest that taking high-dose calcium supplements may increase the risk of coronary heart disease and heart attacks in certain populations, such as postmenopausal women. However, it’s unclear if these effects are associated with taking high-dose calcium without vitamin D, which increases intestinal calcium absorption. When taken alongside vitamin D, calcium supplements haven’t been associated with an increased risk of heart disease or heart attack.

This is why most experts suggest that people increase their calcium intake by boosting their consumption of calcium-rich foods and taking lower-dose calcium supplements in combination with vitamin D.

Calcium supplements may interfere with the following medications:

• Dolutegravir: Taking calcium with dolutegravir may significantly decrease blood levels of this HIV medication. Take dolutegravir at least two hours before or six hours after taking calcium supplements.
• Thyroid medications: Calcium supplements may interfere with the absorption of medications used to treat hypothyroidism (underactive thyroid), such as Synthroid. Thyroid medications should be taken at least four hours apart from calcium.
• Quinolone antibiotics: Calcium supplements may reduce the absorption of certain antibiotics, such as gemifloxacin and ciprofloxacin. These medications should be taken two hours before or two hours after calcium supplements.

It’s also important to take calcium separately from medications like the antiarrhythmic medication sotalol and bisphosphonates, which are used to treat osteopenia and osteoporosis. Taking calcium supplements with these medications can reduce their absorption.

What To Look For

When shopping for calcium supplements, it’s important to consider factors like quality, form, and dosing. To ensure you’re purchasing a high-quality and safe supplement, choose supplements from reputable manufacturers.

It’s best to purchase calcium supplements certified by USP, UL, and NSF International, which are independent organizations that set strict standards for supplement quality and safety. Additionally, it’s suggested to avoid calcium supplements made from unrefined oyster shells, bone meal, or dolomite that do not carry the USP symbol. Products made with these products may contain high levels of toxic metals, which can be dangerous to health.

Calcium supplements are available in several forms, including liquids, powders, chewable products, and capsules.If you have trouble swallowing pills, it’s best to choose liquid, chewable, or powdered calcium supplements.

Lastly, because calcium supplements aren’t necessary or appropriate for everyone and high-dose calcium has been linked with several adverse health outcomes, it’s best to talk to a healthcare provider before you start taking calcium supplements.

While consuming foods rich in calcium is safe and not associated with adverse side effects, taking large doses of supplemental calcium can lead to negative health outcomes.

The Tolerable Upper Intake Level (UL), which is the maximum daily intake of a nutrient unlikely to cause harm, is currently set at 2,500 mg per day for adults aged 19 to 50 and 2,000 mg per day for adults over the age of 51. The UL only applies to supplemental calcium, not dietary sources.

Taking very high doses of calcium for long periods may cause calcium deposits to build up in the arteries, which can increase the risk of heart disease and heart attacks. A 2021 review of 13 studies that included over 28,000people found that supplementary calcium intake of 1,000 mg per day significantly increased the risk of heart disease by about 15% in healthy postmenopausal women.

Additionally, some evidence suggests that high-dose calcium supplementation of over 1,500 mg per day may increase the risk of prostate cancer and prostate cancer mortality. High-dose calcium supplementation has also been linked to an increased risk of kidney stones and age-related macular degeneration (ARMD), which is currently the leading cause of vision loss in older adults.

Though calcium supplements may be necessary for certain people, high-dose supplementation may increase the risk of developing several health conditions. For this reason, calcium supplements should only be taken when necessary and should be monitored by a qualified healthcare provider, especially when taken in higher doses.

Side Effects of Calcium

Calcium supplements are associated with several side effects. For example, calcium carbonate, one of the most common forms of calcium used in dietary supplements, may lead to digestive symptoms such as:

• Bloating
• Gas
• Constipation

If you’re experiencing digestive symptoms after taking calcium supplements, taking your supplement with food may reduce these side effects.

Research also suggests that high-dose calcium supplements may also increase the risk of health conditions like age-related macular degeneration (AMD), heart disease, kidney stones, and metabolic syndrome, so it’s important to follow dosing recommendations from your healthcare provider and stick to low doses of calcium whenever possible.

Calcium is a mineral that plays essential roles in health, from providing structure to the bones and teeth to regulating muscle function. It's concentrated in foods like yogurt and leafy greens and can also be taken as a dietary supplement.

Calcium supplements aren’t appropriate for everyone, but they may help increase bone mineral density, improve PMS symptoms, and prevent preeclampsia in certain populations. Plus, calcium supplements are necessary for people who can’t maintain adequate calcium levels through diet alone.

Calcium supplements are generally considered safe when taken in appropriate doses but may increase the risk of health conditions like heart disease and certain cancers when taken in large amounts over long periods of time. If you’re interested in taking calcium supplements, talk to your healthcare provider. They can help you decide whether calcium supplements are the right choice for your specific health needs.