Calcium is one of the most well-known but misunderstood minerals. It is added to everything from cereal to orange juice, yet there is a lot of evidence that supplements are not effective and may even be harmful…
Calcium Supplements: The Problem
There are several supplements that I personally take daily, even when eating a very high-quality real food diet because it is difficult to get enough of these nutrients from our modern food supply.
Other vitamins and minerals (like calcium and sometimes folic acid and iodine) are actually over-abundant in our current food supply and may be harmful.
Calcium is naturally found in dairy products and is often added to dairy and dairy-substitutes. Calcium is also added to many processed foods, cereals, breads and juices. Many people also take calcium supplements, especially during pregnancy and post-menopause, but recent research calls this practice into question.
Like so many other nutrients, Calcium needs cofactors (other vitamins and minerals) to be absorbed. Without these, calcium supplements are not bioavailable and may be harmful.
A 2012 study published in the British Medical Journal showed that those who took calcium supplements had a 139% higher risk of heart attack, though this increased risk was not present when the same amount of calcium was consumed from whole food sources. (1)
Other studies have shown the same correlation:
- A 2010 meta-analysis showed that calcium supplementation increased the risk of stroke, heart attack and death from all causes (2)
- A study published in JAMA in 2013 showed that supplementation in excess of 1,000mg/day was associated with a 20% increase in risk of death from cardiovascular disease. (3)
- Other studies, like a recent one published in the American Journal of Clinical Nutrition showed that calcium supplementation increased risk of kidney stones and prostate cancer (4)
- Chris Kresser showed that this risk is even higher in women “Additionally, a recent Swedish study reported a 40% higher risk of death among women with high calcium intakes (1400 mg and above), and a 157% higher risk of death if those women were taking a 500 mg supplement daily, compared to women with moderate daily calcium intakes (600-1000 mg).” (5)
So why does it appear that calcium supplementation can increase the risk of heart related problems?
Two possible reasons…
- Researchers speculate that when supplemental calcium is taken, it cannot all be absorbed and the excess is left circulating in the blood, which can lead to calcification in the arteries, or is excreted in urine, which may lead to kidney stones. (Here are natural remedies for kidney stones.)
- It is very difficult for the body to absorb many forms of calcium, especially when they are taken alone, as it needs cofactors like Vitamin K2, Magnesium and Vitamin D to be properly utilized.
Calcium for Bone Health?
But, what about bone health? Turns out, calcium supplements aren’t the silver bullet for bone health either…
A 2012 study showed that supplemental calcium (above the recommended amount from food) did not increase bone density or reduce fracture rate. (6)
In fact, in 2013, the United States Preventative Services Task Force reviewed 135 studies on calcium and rate of fractures and recommended that post-menopausal women STOP taking supplemental calcium. (7)
Food sources of calcium (like dairy, bone-in meats and certain types of fish) were shown to be beneficial for bone health without the increased risk of cardiovascular and other problems.
Dairy is the most recommended dietary source, but there are some confounding factors. Numerous studies in several countries have shown that dairy consumption reduced the risk of osteoporosis, hypertension and other problems associated with these diseases. (8,9,10)
Some in the natural health community claim that dairy is actually bad for bones because dairy products acidify the body, causing it to pull calcium from the bones to re-alkalize.
Chris Kresser thoroughly explained (and debunked) this theory, and a 2011 study reviewed this theory and found no scientific evidence to substantiate it. (11)
A Better Option: Food Sources of Calcium
The available literature points to the same conclusion that many of us feel intuitively- that food sources are better than supplements whenever possible and this is especially true with calcium.
Dairy is a controversial topic, since many people do not tolerate it or choose not to consume it. Fortunately, while it is the most well-known dietary source of calcium, it is by no means the only source and others may be better. Also, research suggests that the most beneficial part of dairy (especially raw dairy) for bone health may be Vitamin K2, not calcium. More on that below…
Wonderful non-dairy sources of calcium include:
- Sardines (canned)
- Salmon, with bones (canned)
- Leafy Greens
- Blackstrap Molasses
The Importance of Cofactors
Cofactors are also vital for proper calcium absorption and use in the body. In isolation, calcium (and many nutrients) can be harmful, as I explained above, but it is vital and helpful when consumed in proper balance with its cofactors.
There is an excellent book called Vitamin K2 and the Calcium Paradox, which explains in depth how Vitamin K2 is needed for proper utilization of calcium and how calcium consumption without K2 can lead to health problems.
K2 is found in raw dairy from pastured cows, liver, aged cheeses and natto (a fermented soy product). It is also available in supplement form.
Other cofactors for calcium include Vitamin D and Magnesium (among others). In fact, K2, Calcium, Magnesium and D3 are all better utilized when consumed together.
Personally, I prefer to get my Vitamin D from the sun whenever possible and my calcium from food, but I take supplemental forms of Vitamin K2 and use transdermal magnesium to keep my levels in optimal ranges. (This is a great quiz to see if you are deficient in magnesium).
Supplemental calcium is not the panacea for strong bones that it is made out to be. Calcium is certainly important, but it is most beneficial when it comes from food sources and when taken in proper ratio with its cofactors.
Do you take calcium supplements?
Discussion (52 Comments)
My mom was told to take very high daily amounts of calcium supplement daily because the med she was put on after completing radiation for breast cancer depletes bones. Anyone have any experience with this? I’m going to share this info with her.
My mother was told the same thing, and I’m concerned about this. She won’t listen to me, only her doctors… I have heard that carbonate can, in addition to everything described above (and was mentioned) can also cause “brain gravel”, which has been found in patients with Alztheimer’s. My Nana (her mother) died from that and breast cancer, caught extremely late, in her early 80s, and she passed a decade ago next month at 84. My Mom was lucky, she detected it early, had surgery, and chemo + radiation, and it seems to have all been removed. But this frightens me.
I’m glad to hear the magnesium (Mg) is helping with the muscle cramps and vertigo. The list I have of problems related to a low magnesium is lengthy, but I don’t think it was all inclusive. Magnesium is classed as an essential mineral and is used by every body system. It may not be known all the symptoms of low Mg. I’ve been surprised by the difference in symptoms from person to person.
You didn’t mention how much Mg you’re taking. Have you noticed any other problems that the Mg has helped? Also, my apologies for my delayed response. I had planned to do another blog on Mg. I’ll add your comment to the discussion.
I’m very pleased to have come upon this site. In another post you site the use of magnesium supplements which I have been taking since experiencing muscle cramps. Much later after convalescing from a knee replacement I began to experience severe vertigo while lying down and standing up. A therapist said that vertigo is due to the build up of calcium carbonate crystals on the cilia of the inner ear (responsible for balance). I noticed (correct me if I’m wrong) that there was no mention of vertigo as a problem for lack of magnesium in that other post. As it were, I have been taking Mg supplements along with plenty of water to help dissolve the crystals. Muscle cramps and vertigo are no longer a problem.
A few months after I started taking calcium supplements, I got kidney stones! So painful. Don’t want to do that ever again!!!
Sorry to hear that. There are different types of calcium, but I don’t remember which kind is more prone to forming kidney stones. My doctor put me on calcium about 5 years ago and I’ve had no problems with it.
Interesting article. As a Naturopath I see first hand the effects of poor nutrition and over supplementation. Whilst I am in agreement with the main basis of your article, calcium supplementation remains a useful tool for those who need it and people need not fear it. Bottom line is compliance; not everyone is going to eat healthfully enough to guarantee the levels of calcium and co-factors needed for therapeutic effect. So the need for supplementation arises and remains.
This is where you need to obtain professionally formulated supplements that do have all needed co-factors for proper absorption and the way to do this is through visiting your Naturopath or Doctor for testing to ascertain what minerals etc need to be supplemented and by how much and for how long. This is the real point here; professionally formulated supplements used under supervision after testing, not using poorly made retail lines with no idea what you are doing.
I see many people on a daily basis who over use supplements of all kinds and they do contribute to imbalances. Whilst the research is good it fails to take into account whether or not people were supplementing under supervision or what quality of supplements they were using so we are left to assume that.
What I can tell you is that a properly designed supplementation program administered under supervision is the best option if you are thinking along those lines and I highly recommend seeing your Naturopath or Doctor before you embark on such a regime. 🙂
Thank for the article Katie. I think everyone would agree that whole-food options are always the best choice for all vitamins and minerals, but of course that isn’t always possible, so it is important to think about what you are putting in your body and why.
One note: I appreciate that in your article you specifically mention raw dairy. Not all dairy is created equal and the nutritional differences between the grocery store pasteurized, homogenized dairy and fresh, raw dairy are plentiful. Raw dairy is a living food that has a plethora of pre- and pro-biotics, vitamins, and minerals. If you think you are lactose intolerant or “can’t tolerate” regular, grocery store milk, I truly recommend seeking out a raw milk source close to you and trying it. Your body will thank you!
What about calcium supplement use during a fever? white blood cells needs calcium to be produced. During a fever, WBC production is up, therefore so is calcium demand, which is taken from the bones, which in turn causes the ache. First, is this true, and if it is, is a supplement helpful? I would think that it would provide the extra calcium necessary so it wouldn’t have to be taken from the bones. What kind of supplement would be best, if it should be taken at all? Or would some good bone broth do the trick?
I am in the sun a lot EVERY day; yet with my last blood panel evaluation I still showed low vit D. My doctor says most individuals are low in this area and supplementation is always beneficial. Since I’ve been taking D3 sups, my nails and hair have noticeably improved!!!
Thanks for all your invaluable information!!
Very interesting post. I’ve recently starting putting a small amount 1/4 teaspoon of ground eggshells (organic and no soy in the feed) into my daily routine. I’ve heard that the calcium from eggshells is better assimilated in the body than the calcium from supplements. I wonder if this source of calcium from shells would be less likely to produce some of the negative outcomes as mentioned in your post. Not sure if I should continue with eggshells now.
I take calcium supplements every day…2 & 3 times a day actually…
all the blood tests I’ve had, & all the CT Scans I have had, have not shown anything wrong or out of place…
I’m a cancer survivor (15 yrs), so I have frequent flyer miles when it comes to scans & blood work.
I have always been a healthy eater & always in the best of health (till I got cancer from where I worked)….I started taking supplements when I was in the military @ 19 yrs old…I retired in 1999 & in february of 2000 I was diagnosed with head/neck cancer….I can no longer eat regular food like everyone else does….so I depend on supplements to fill in the nutritional gaps.
I’m like the toy weebles from yrs past…”…weebles wobble, but they don’t fall down…”
Life keeps knocking me down, & like the weebles, I keep bouncing back up. : )