Answers to Common Questions about Calcium Supplements

Betty Chaffee/ April 28, 2020/ Dietary Supplements, Self management/ 5 comments


One dietary supplement that people frequently use is calcium. Some of the most common questions I've had from patients involve calcium supplements. Who should take them? What's the right dose? And there are some common misunderstandings about how calcium works and how it should be taken. So let's talk about calcium! 

What are calcium supplements good for?

Calcium is a major component of bones. Calcium makes bones strong, able to carry our weight and take impact without breaking. Without calcium, bones become weak; that can result in fractures with all the discomfort and recovery that goes along with them.

Calcium has other uses in the body too. It plays a part in the nervous system, muscles,and healing, along with many other functions. Calcium needs to be present in the blood in order to carry out all these other functions. And the body is pretty smart - if the blood level of calcium starts to decrease, calcium will be taken out of the bones in order to make sure all those other body processes work well. A common misunderstanding is that a normal blood level of calcium means calcium supplementation isn't needed. But it turns out that because the body just starts taking calcium from bone, the blood level doesn't predict whether the bones have enough calcium to stay healthy. Everyone, regardless of age, needs to be sure their calcium intake is enough to keep bones strong.

Who needs to be thinking about calcium intake?

Though everyone should pay attention to bone health, we tend to start thinking about it more as we age. For women, the presence of estrogen helps in several ways to keep bones strong. The estrogen level in the body begins to decrease as women enter menopause, and the protective effect on bones is lost over time. So when women hit about 50 years of age, consideration of calcium intake becomes more important. Men tend to have more long-lasting bone strength, but after about the age of 70 they, too, need to be more aware of getting adequate calcium.

How much calcium do you need?

First, it's important to note that calcium recommendations are based on intake of elemental calcium. Most products contain calcium attached to something else, like carbonate (calcium carbonate) or citrate (calcium citrate). When you read the label be sure you know how much actual calcium is in each tablet, not how much carbonate or citrate is there. Be sure to ask your pharmacist if the label isn't clear.

Recommended daily calcium intake for women up to age 50 and men up to age 70 is 1000mg. For reasons described above, calcium intake should increase to 1200mg daily for women over 50 and men over 70. Recommended daily calcium intake for all age groups has been published here by the National Institutes of Health. 

But that doesn't necessarily mean you have to take 1200mg of calcium supplements. In fact, research shows that getting nutrients from the diet whenever possible is the best way to maintain healthIf you eat a balanced diet, you are likely getting some calcium from dietary sources. How much? Depends on what you typically eat. Calcium is found in lots of dietary sources, including dairy products like milk, yogurt, cottage cheese, and cheese. It's also in some nuts, eggs, seafood, and green vegetables. Some adults become lactose-intolerant, too, as time goes on, so that the consumption of milk and other dairy products becomes uncomfortable. That can make it tough to get adequate calcium from dietary sources. I recommend taking a week or 10 days to keep a log of how much calcium you get on a day-to-day basis. It wll mean looking carefully at nutritional labels and keeping track, but it'll be worth it in the end to know if your calcium intake is close to zero, close to the recommended daily amount, or somewhere in between.

Once you know how much calcium you typically eat, you can decide how much supplement you need to get close to that daily goal. Keep in mind, it doesn't have to be exact. If you go a little over or a little under, that's fine. 

The most common side effects of calcium are constipation and stomach discomfort. Some recommend starting supplementation slowly to decrease the risk of those side effects. There's also been a controversy in recent years about whether high does of calcium can increase the risk of heart problems, but at this point most experts believe the advantages of adequate calcium intake outweight the possible risk. Best to get an idea of your dietary calcium intake, and then use supplements if you need to.

How should you take calcium?

Another common misunderstanding among patients is that it's okay to take the entire daily amount of calcium at one time. It turns out that the body is only efficient at absorbing about 500-600mg of calcium at once. So taking the entire 1200mg at once is not likely to provide the same benefit as taking 600mg twice daily. If you find that your diet contains little calcium and you need to supplement with the entire amount, be sure to take it in divided doses.

And be aware that some calcium products should be taken with food in order to be absorbed well. Other products can be taken with or without food. You'll find that information right on the label, so be sure to pick a product that fits into your daily schedule.

What products are out there?

Well, just like all dietary supplements there are many calcium products available. After deciding how much calcium supplementation you need, here are some things to keep in mind when shopping for the right product

  • Look for a product that you can trust - either a brand name or a generic with a seal of approval to be sure it's been tested for purity and potency

  • Look at the label carefully - how much elemental calcium is contained in each serving? And what, exactly, is a serving? Is it one tablet? Two? Three? A common misunderstanding is that the amount listed per serving on the label means that's the amount contained in one tablet or capsule. That's often not the case, so read carefully.

  • As mentioned above, read the product label to find out if it needs to be taken with a meal.

  • If you take a multivitamin, be sure to read its label carefully before going out to purchase a calcium supplement. Many daily multivitamins contain calcium, and there's no need to purchase something new if you're already getting enough calcium in your vitamins!

Keep your bones strong by making sure you get enough calcium!

If you take prescription medicine, check with your pharmacist or with us at BetterMyMeds to make sure there are no drug interactions to think about. And if you have questions about calcium supplementation that aren't answered here, leave a comment below or contact us at BetterMyMeds. We're here to help!



Betty Chaffee, PharmD, is owner and sole proprietor of BetterMyMeds, a Medication Management service devoted to helping people get the maximum benefit from their medications.
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  1. This is interesting. I had to grab my bottle of multi-vitamin (for men 50+) to see how mine measures up. The label on my vitamin shows Calcium 210 mg and 16% DV. The ingredients list Calcium Carbonate but I have to assume that the 210 mg IS an elemental calcium amount.

    1. Tony —
      Your assumption is right. On your label the listing of calcium means just the calcium part, not the carbonate part. But sometimes it’s hard to tell I think manufacturers are starting to do a better job of making it clear than they were a few years ago.

  2. When I buy vitamins, my wife always makes comments like “…those are synthetic vitamins and not as good as the natural vitamins we get in our food”. The last bottle I brought home was Centrum Silver for men 50+. I’m not sure how to tell the difference between what may be synthetic vitamins and actual vitamins.

  3. Good question Tony. I’m guessing your wife means that getting nutrients from the foods they naturally occur in is better than getting nutrients from supplements. That’s similar to what I’ve been saying too. I’ve never researched it, but from what I know about drug manufacturing, the likelihood is that all (or nearly all) dietary supplements contain vitamins that are synthesized in the lab. That would be the most efficient way to make a vitamin tablet, rather than trying to extract it from the food it’s contained in. When you eat vitamins in food, though, you’re usually going to get the naturally occurring compound.

    Of course, that’s not always true. When we drink milk “fortified with vitamin D” we’re likely getting synthetic vitamin D. But it’s hard to find vitamin D in food – generally we get our vitamin D when our skin makes it in response to sunlight. So there are exceptions to every rule, right?

  4. Pingback: The Importance of Calcium and Vitamin D for Bone Strength - BetterMyMeds

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