The Lowdown on Calcium Supplements
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.
Calcium supplements are some of the most commonly used dietary supplements in the United States. But there are a lot of misunderstandings about calcium. In fact, 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 bone structure. Calcium makes bones strong, able to carry our weight and take impact without breaking. Without calcium, bones can become weak, increasing the risk of fractures. The discomfort, extended recovery, and possible disability that results can have a huge impact on our lives.
Calcium has other uses in the body too. It plays a part in the nervous system, muscle activity, healing, and many other functions. Calcium needs to be present in the blood in order to carry out all those functions. And our bodies know how to keep the blood level of calcium in a safe range. If the blood level gets too low, our body takes calcium out of our bones to make it go back up. A common misunderstanding is that a normal blood level of calcium means calcium supplementation isn't needed. But because the blood level is adjusted by taking calcium from bone, it turns out that the blood level can't predict whether the bones have enough calcium to stay strong. Everyone, regardless of age, needs to be sure their calcium intake is enough to keep bones healthy.
Who needs to be thinking about calcium intake?
People of all ages should pay attention to bone health. When we're young, we're forming bone to last us a lifetime. As we approach our thirties, we'll have made our bones as strong as they'll ever be. Making sure we get enough calcium when we're young puts us in an excellent spot as we begin to age. As we approach 50 and beyond, we begin to lose more bone than we make. So making sure we get enough calcium is important throughout our lives.
But we tend to start thinking about calcium and bone strength more as we age. For young and middle-aged women, estrogen does a wonderful job of keeping bones strong. Once women enter menopause that protective effect gradually declines. 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 health. If you eat a balanced diet, you are likely getting some calcium from dietary sources. How much you get 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 develop lactose intolerance, 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'll 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 outweigh 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 supplements?
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 daily multivitamin, be sure to read its label carefully before going out to purchase a calcium supplement. Some daily multivitamins contain calcium, so you'll want to know how much that adds to your total.
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!
Originally published April, 2020; updated May, 2023