take calcium supplements hoping to strengthen their bones.
However, they may have drawbacks and even health risks,
including raising the risk of heart disease (1).
This article explains what you need to know about calcium
supplements, including who should take them, their health
benefits and potential risks.
Why Do You Need Calcium?
In the bloodstream, it’s used to send nerve signals, release
hormones like insulin and regulate how muscles and blood
vessels contract and dilate (2).
It’s so important that if you don’t get the recommended amount
in your diet, your body will take it from your skeleton and
teeth to use elsewhere, weakening your bones.
So how much calcium do you need each day?
Below are the current recommendations from the Institute of
Medicine, by age (2):
- Women 50 and younger: 1,000 mg per day
- Men 70 and younger: 1,000 mg per day
- Women over 50: 1,200 mg per day
- Men over 70: 1,200 mg per day
There are also recommended upper limits for calcium intake. The
cap is 2,500 mg per day for adults up to age 50 and 2,000 mg
per day for adults over 50 (2).
It’s possible to get sufficient amounts through your diet.
Foods that contain it include dairy products, certain leafy
greens, nuts, beans and tofu.
However, people who don’t eat enough calcium-rich
foods might consider taking supplements.
Bottom Line: Your body uses calcium to build
strong bones, send nerve signals and contract muscles. While
it’s possible to get enough of it in your diet, some people
might need to consider supplements.
Who Should Take Calcium Supplements?
When your calcium intake is insufficient, your body will remove
calcium from your bones, making them weak and brittle. This can
result in osteoporosis.
Since women are at a higher risk of osteoporosis, many doctors
recommend that they take calcium supplements, especially after
Because of this, older women are much more likely to take
calcium supplements (2).
If you don’t get the recommended amount through your diet,
supplements can help fill the gap.
You might also consider calcium supplements if you:
- Follow a vegan diet.
- Have a high-protein or high-sodium diet, which may cause
your body to excrete more calcium.
- Have a health condition that limits your body’s ability to
absorb calcium, such as Crohn’s disease or inflammatory bowel
- Are being treated with corticosteroids over a long period
- Have osteoporosis.
Bottom Line: Calcium supplements may benefit
those who are not getting enough calcium from food and women
who have reached menopause.
The Benefits of Calcium Supplements
Calcium supplements may have several health benefits.
They May Help Prevent Bone Loss in Postmenopausal Women
women lose bone mass due to a decline in estrogen.
Luckily, supplements may help. Several studies have suggested
that giving postmenopausal women calcium supplements — usually
around 1,000 mg per day — may reduce bone loss by 1–2%
The effect seems to be greatest in women with low calcium
intakes and during the first two years of taking supplements.
Plus, there doesn’t seem to be any additional benefit to taking
larger doses (4).
They May Help With Fat Loss
Studies have associated low calcium intake with a high body
mass index (BMI) and high body fat percentage (5).
A 2016 study examined the effects of giving a daily 600-mg
calcium supplement to overweight and obese college students
with very low calcium intakes.
The study found that those given a supplement containing 600 mg
of calcium and 125 IUs of vitamin D lost more body fat on a
calorie-restricted diet than those who did not receive the
It’s often recommended to take vitamin D
with calcium, since it improves its absorption.
Calcium May Help Lower the Risk of Colon Cancer
According to one large study, calcium from dairy products and
supplements may lower the risk of colon cancer (7).
An earlier review of 10 studies found similar results (8).
Supplements May Help Improve Metabolic Markers
Several studies have suggested that taking calcium supplements
might improve metabolic markers, especially when taken with
In a 2016 study, 42 pregnant women took supplements containing
calcium and vitamin D. Several of their metabolic markers
improved, including blood pressure and markers of inflammation
Other research has shown that the children of women who took
calcium supplements while pregnant have lower blood pressure at
age seven than the children of mothers who did not take them
In a recent study, more than 100 overweight, vitamin
D-deficient women with polycystic ovary syndrome (PCOS) were
given either a calcium and vitamin D supplement or placebo
However, other studies have shown no improvements in the
metabolic profiles of dieters who took supplements containing
both calcium and vitamin D (6).
Bottom Line: Studies have linked taking
calcium supplements with a lower risk of colon cancer and
blood pressure, as well as fat loss and increases in bone
Possible Dangers of Calcium Supplements
Recent research suggests that calcium supplements may, in fact,
cause some health problems. However, the evidence is mixed.
They May Increase Risk of Heart Disease
Perhaps the most controversial suggestion about calcium
supplements is that they may increase the risk of some types of
heart disease, including heart attack and stroke.
More conclusive research is needed to determine the effect of
calcium supplements on heart health.
High Levels May Be Linked to Prostate Cancer
High levels of calcium may be linked to prostate cancer,
although the research on this link is also conflicting.
However, a randomized controlled study that gave 672 men either
a calcium supplement or placebo every day for four years showed
that participants did not have an increased risk of prostate
In fact, participants who took the supplement had fewer cases
of prostate cancer (21).
Other research has suggested that dairy
products may be the culprit. A review of 32 articles
reported that consuming dairy products — but not calcium
supplements — was linked to an increased risk of prostate
Risk of Kidney Stones May Increase
There is some evidence that calcium supplements increase the
risk of kidney stones.
One study gave more than 36,000 postmenopausal women either a
daily supplement containing 1,000 mg of calcium and 400 IU of
vitamin D or a placebo pill.
The results showed that those who took the supplement had an
increased risk of kidney stones (27).
Furthermore, while supplement users in the study experienced an
overall increase in hip bone density, they didn’t have a lower
risk of hip fractures.
Consuming more than 2,000 mg of calcium a day from your diet or
supplements is also linked to an increased risk of kidney
stones, according to the Institute of Medicine (2).
Other sources say that the risk of kidney stones increases when
calcium intake exceeds 1,200–1,500 mg per day (28).
High Levels of Calcium in Your Blood
Having too much calcium in your blood leads to a condition
called hypercalcemia, which is characterized by many negative
symptoms, including stomach pain, nausea, irritability and
It can be caused by several things, including dehydration,
thyroid conditions and taking high levels of calcium
Excessive vitamin D supplements may also lead to hypercalcemia
by encouraging your body to absorb more calcium from your diet.
Bottom Line: Calcium supplements may
increase the risk of heart disease and prostate cancer,
although the link is unclear. Extremely high levels of
calcium from any source may have negative health effects.
Things to Consider When Taking Calcium Supplements
If you take calcium supplements, there are several factors you
should be aware of.
How Much Should You Take?
Calcium supplements can help fill the gap between how much
calcium you get in your diet and how much you need per day.
Remember, the recommended amount for most adults is 1,000 mg
per day and increases to 1,200 mg per day for women over 50 and
men over 70.
Therefore, if you typically only get around 500 mg per day
through food and need 1,000 mg per day, then you can take one
500-mg supplement daily (28).
However, choose your dose wisely. Taking in more calcium than
you need can cause problems (29).
You May Need to Split up the Dose
It’s important to check the amount of calcium in the supplement
Your body can’t absorb large doses of it at once. Experts
recommend taking no more than 500 mg at a time in supplement
Make sure to tell your doctor and pharmacist if you are taking
calcium supplements, since they can interfere with how your
body processes certain medications, including antibiotics and
This way the calcium is less likely to inhibit the absorption
of the zinc, iron and magnesium that you consume in your meal.
Dangers of Too Much Calcium
Remember, you only need 1,000–1,200 mg of calcium each day.
There’s no benefit to taking more than that. In fact, you could
experience problems if you do.
Problems include constipation, hypercalcemia, calcium buildup
in soft tissues and trouble absorbing iron and zinc (2).
Bottom Line: When you’re taking calcium
supplements, it’s important to consider the type, amount and
whether they may interact with other medications you take.
Different Types of Calcium Supplements
Calcium supplements come in different forms, including tablets,
capsules, chews, liquids and powders.
One key difference between these types of supplements is the
form of calcium they contain.
The two main forms are:
- Calcium carbonate
- Calcium citrate
These two forms differ in how much elemental calcium they
contain and how well they’re absorbed. Elemental calcium refers
to the amount of calcium that is present in the compound.
This is the cheapest and most widely available form. It
contains 40% elemental calcium and therefore usually delivers a
lot of calcium in a small serving.
However, this form is more likely to cause side effects, such
as gas, bloating and constipation. It is recommended that
calcium carbonate be taken with food for optimal absorption
This form is more expensive. Twenty-one percent of it is
elemental calcium, meaning you may need to take more tablets to
get the amount of calcium you need.
However, it’s more easily absorbed than calcium carbonate and
can be taken with or without food.
Calcium citrate is the form recommended for people with
irritable bowel syndrome.
It’s also the better choice for those with low levels of
stomach acid, a condition common among older people and those
taking medications for acid reflux (30).
Bottom Line: The two main forms of calcium
supplements are calcium carbonate and calcium citrate.
Calcium carbonate needs to be taken with food and is less
effective if you have low levels of stomach acid.
Food Sources of Calcium
It’s best to get nutrients from food rather than supplements.
Nevertheless, if you think you’re not getting enough calcium in
your diet, consider eating more of these foods:
- Dairy, including milk, cheese and yogurt
- Canned fish
with bones, such as salmon or sardines
- Certain leafy greens including collard greens, spinach and
- Edamame and tofu
- Beans and lentils
- Fortified foods and drinks
Bottom Line: You can get all the calcium you
need each day from food. Calcium-rich foods include yogurt,
certain leafy greens, tofu and canned fish.
Take Home Message
Calcium supplements can help people who are at risk of
osteoporosis, as well as those who don’t get enough calcium in
While some research suggests a link between calcium supplements
and heart disease, the link is not clear.
However, it is known that getting more than the recommended
amount of calcium from any source may raise your risk of kidney
Calcium supplements are probably fine in small doses, but the
best way to get calcium is from food. Strive to incorporate a
variety of calcium-rich foods in your diet, including non-dairy