Next to multivitamins, calcium supplements are among the most popular nutritional supplements people take. Calcium is best known for its role in preserving bone health. Yet, your body needs calcium on a minute-by-minute basis for cell-to-cell communication, muscle contractions, hormone release, blood clotting, and a normal heart rhythm. Ninety-nine percent of the calcium in your body is stored in your bones and teeth, but the other 1% is the most important with regard to sustaining life. If the 1% of calcium that isn’t in your bones falls too low, you can die.
Seeing that calcium is essential for short-term survival and long term for bone health, taking a calcium supplement has become popular. For years now, health care professionals have urged women to take calcium for healthy bones and to lower the risk of osteoporosis. This sounds like a good idea, but a number of studies suggest that taking calcium in supplement form may, in fact, be harmful.
Calcium and Heart Health
Why the concerns about calcium supplements? Several studies show a link between calcium supplements and a greater risk of heart disease and heart attacks. In fact, a study of 400,000 women and men that lasted almost 20 years found men who took calcium supplements had a 20% higher risk of heart attack. The same wasn’t true of women, although other research also suggests that calcium supplements may increase the risk of heart attack and stroke in women too.
Further supporting the idea that calcium supplements aren’t necessarily healthy was a study carried out in 2016. This study showed the risks of taking a calcium supplement outweighed the potential benefits. As you know, many doctors still recommend calcium supplements for women after menopause. The idea is that taking calcium helps prevent bone loss and osteoporosis, but as you’ll soon see, this may not be the case.
You might wonder how taking a calcium supplement could be harmful? The concern is that excess calcium that you get from supplements is deposited along the inside walls of blood vessels where it contributes to plaque formation. This deposition of calcium may, in turn, contribute to heart disease and heart attacks. Another theory is that when you take calcium in supplement form, it causes a spike in calcium that promotes calcium deposition inside blood vessels. Food sources don’t cause spikes in calcium, Instead, they cause a more modest but sustained rise in calcium.
Other Risks of Taking a Calcium Supplement
Calcium supplements, but not dietary calcium, also increases the risk of kidney stones. What’s interesting is dietary calcium seems to reduce the risk of developing kidney stones. So, supplements and dietary calcium have very different effects on kidney stone risk. Other than avoiding calcium supplements, the most important thing you can do is drink more water and unsweetened lemonade. The citric acid in lemonade helps prevent kidney stones from forming.
Although calcium supplements may have drawbacks, getting enough calcium lowers the risk of at least one cancer – colon cancer. Colon cancer often arises from colon polyps. A study showed people who took calcium supplements for four years had a lower risk of developing recurrent colon polyps. Interestingly, the risk stayed low even after subjects stopped supplementing with calcium.
Does a Calcium Supplement Increase the Risk of Dementia?
Are calcium supplements harmful to your brain as well? Of concern is a recent study linking calcium supplements to a greater risk of memory loss and dementia – but only in certain women. This study showed that women who had had a stroke or who had clogged arteries in the brain and took calcium supplements had an almost seven times higher risk of developing dementia. Keep in mind, this was an observational study and doesn’t necessarily show calcium supplements CAUSE dementia. Yet, it does raise questions, particularly in the light of studies linking calcium supplements with heart disease and stroke. It also didn’t apply to women with a normal brain scan, meaning they had no evidence of brain atherosclerosis.
The Reason for Taking a Calcium Supplement May Be Flawed
The reason most people take calcium supplements is to prevent bone loss. Unfortunately, recent studies show that the combination of calcium and vitamin D in supplement form may NOT prevent bone loss after all, at least when you take it later in life. In fact, the evidence is strong enough that the United State Preventive Services Task Force recommended that women not take calcium combined with vitamin D after menopause. This doesn’t mean you don’t need calcium, it questions whether it’s safe to take calcium supplements.
Despite these concerns, it’s important that you meet your body’s calcium requirements by eating a diet that contains sufficient calcium. You should be able to do this rather easily if you eat a varied diet and don’t have dietary restrictions. It’s possible, but a bit more challenging, to get enough calcium when you don’t consume dairy. Fortunately, a number of plant-based foods are rich in calcium, including tofu, leafy greens, dried beans, broccoli, and almonds. If you don’t consume dairy, you’ll need to eat more of these foods.
Are there situations where you might need a supplement? If you have a digestive issue, like inflammatory bowel disease or celiac, you may not be able to absorb enough calcium from your digestive tract. In this case, you may need a calcium supplement to avoid calcium deficiency. If that’s the case for you, talk to your doctor about your options.
The Bottom Line
If you’re otherwise healthy and eat a varied diet, get your calcium from dietary sources rather than supplements. If you already have osteoporosis or have had a fracture, this may not apply. In this case, discuss with your doctor what’s right for you. Don’t forget, high-impact exercise and high-intensity resistance training also boosts bone health and helps prevent bone loss and osteoporosis. Don’t take a shortcut and focus your entire osteoporosis prevention strategy around calcium supplements. For one, they may not be effective and, secondly, they may be harmful. Stay active, pump some iron, and make sure you’re eating enough calcium-rich foods.
Science Daily. “Benefits of calcium supplements may be outweighed by cardiovascular risks”
Cleveland Clinic. “Study: Calcium Supplements Linked to Dementia Risk in Some Women”
PubMed Health. “Calcium supplements linked to post-stroke dementia in women”
WebMD. “Calcium May Reduce Colon Cancer Risk”
WebMD. “Calcium Supplements Tied to Kidney Stone Risk”
UW Hospital Metabolic Stone Clinic. “Citric Acid and Kidney Stones”
U.S. Preventive Services Task Force. “Vitamin D and Calcium to Prevent Fractures: Preventive Medication”
JAMA Intern Med. 2013;():1-2. doi:10.1001/jamainternmed.2013.3769.
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