Calcium Supplements: Good for Bones, But Bad for the Heart?

Calcium supplementation is very popular, especially among postmenopausal women concerned about bone health. However, there is also a concern about whether calcium supplements increase the risk of cardiovascular events. This post will explore whether or not that is true. But first, let’s look at some basic information about calcium. 

Why is Calcium so Important to Overall Good Health? 

In addition to supporting bone formation and bone density, calcium plays a crucial role in the following bodily functions:

• Muscle function 

• Blood clotting 

• Hormonal secretions

How Much Calcium Do We Need?

That depends a great deal on age and gender:

• 0–3 years old,  200-700mg

• 4-8 years old, 1,000 mg

• 9-18 years old, 1,300 mg

• 19-50 years old, 1,000 mg

• 51-70 years old, 1,000 mg for men & 1200 mg for women

• Over 70, 1,200 

Note that calcium needs dramatically increase as children grow. Unfortunately, almost 50% of American children are not getting adequate calcium. Calcium requirements plateau in midlife. But over 50,  women seem to have an increased need for calcium to ward off loss of bone mineral density (BMD) caused by a dip in estrogen levels (NIH, 2022). 

Food sources of calcium: 

• Dairy – contains by far the most absorbable form!

• One serving of Greek yogurt may contain up to 200 mg of calcium

• One mozzarella cheese stick may contain 220 mg of calcium 

• Soy in all forms is very high in calcium 

• Canned salmon with bones 

• Sardines

• Collard greens contain an amazing 300+ mg per 8-ounce serving

• Figs 

• Nuts and seeds

• Most leafy green vegetables (DiValentino, 2019)

Is Supplemental Calcium the Same as Dietary Calcium?

The body almost always responds best to getting necessary vitamins and minerals through food. Generally speaking, whenever there is a concern about “taking too much” of a vitamin or mineral, researchers are referring to supplements. 

Is There a Difference Between Calcium Supplements?

The most common calcium supplement (and least expensive) is calcium carbonate which is poorly absorbed by older individuals due to diminished stomach acid production. Calcium carbonate is also the form most likely to cause GI upset (NIH, 2022).

That leaves a lot of other calcium products, such as algae-based calcium, calcium citrate, and calcium as ossein-hydroxyapatite complex (OHC). 

In a three-year study done to compare calcium carbonate (1000 mg) to OHC (712mg), it was found that calcium ossein hydroxyapatite improved lumbar spine BMD. The study was done with over 400 postmenopausal women who did not have osteoporosis.  Those who took the calcium carbonate saw a 3.1% reduction in BMD. Additionally, the OHC was better tolerated.  (Castelo-Branco et al., 2020). 

It is not surprising that OHC appears to be a superior form of calcium for supporting BMD. After all, the complex is very similar to actual bone and as such is used in dental resins, bone grafts, and facial rejuvenation products (NIH, 2022). 

What About Calcium Supplements and Cardiovascular Disease (CVD)?

There are at least 13 quality studies that show an association between calcium supplementation and an increase in CVD. These are studies in which there is a placebo-control group and the studies are double-blinded, indicating that neither the researchers nor the participants knew who received calcium and who received the placebo. 

Researchers concluded that taking 1000 mg of calcium raised the risk of cardiovascular issues by 15% in healthy postmenopausal women. It made no difference if the women were also taking vitamin D (Myunget et al., 2021). 

Augh! I Have Bone Concerns, What Should I Do? 

The first step should be to evaluate the diet to see how much calcium is being consumed. There are plenty of free apps available, including www.cronometer.com. 

Are you able to add in more calcium-rich foods? If not, consider low-dose calcium supplementation ideally in the form of OHC to avoid cardiovascular concerns.  Just because a product says the recommended dose is 1000 mg, doesn’t mean you have to take the 3-4 capsules required to actually ingest that amount. Start at a lower dose. 

If you take calcium supplements, use caution with certain medications including lithium (which may raise calcium) and any thyroid medications. And take them with food in a dose not to exceed 500 mg at a time (NIH, 2022).

Lastly, while the results of clinical studies are super important in making decisions about which supplements to take and at what dose, the fact is even the best nutritionists are winging it to some degree due to the myriad variables that affect bone health. For example, while calcium is important, so is lowering stress, doing weight-bearing exercise, and avoiding acidic foods such as sugar. That is why in my practice, I often take a smorgasbord approach to making nutritional and lifestyle recommendations. The advantage is, that if a client isn’t ready to think about calcium, perhaps they can start by buying small hand weights or by reducing their caffeine intake. 

If you are interested in more information, consider a FREE 15-minute call or an inexpensive, on-demand video on bone health.  

Disclaimer 

The included information is not meant to or should not be used to replace or substitute medical treatment, recommendations, or the advice of your physician or health care provider. The information contained within is strictly for educational purposes and is based on evidence-based nutrition. If you believe you have a medical problem or condition, please contact your physician or healthcare provider. 

References

Calcium Fact Sheet for Health Professionals (n/a) (2022) National Institute of Health (NIH) https://ods.od.nih.gov/factsheets/Calcium-HealthProfessional/

Castelo-Branco, C., Cancelo Hidalgo, M. J., Palacios, S., Ciria-Recasens, M., Fernández-Pareja, A., Carbonell-Abella, C., Manasanch, J., & Haya-Palazuelos, J. (2020). Efficacy and safety of ossein-hydroxyapatite complex versus calcium carbonate to prevent bone loss. Climacteric : the journal of the International Menopause Society, 23(3), 252–258. https://doi.org/10.1080/13697137.2019.1685488

DiValentino, A.,  (2019) Dairy-free foods that are high in calcium. Insider. (https://www.insider.com/calcium-rich-dairy-free-foods-to-build-strong-bones-2019-6

Myung, S. K., Kim, H. B., Lee, Y. J., Choi, Y. J., & Oh, S. W. (2021). Calcium Supplements and Risk of Cardiovascular Disease: A Meta-Analysis of Clinical Trials. Nutrients, 13(2), 368. https://doi.org/10.3390/nu13020368