calcium pills, high blood level of calcium

Until recently, extra calcium was considered essential for good health. Millions of women popped a calcium pill or two every day. They assumed there were no calcium side effects, though some complained that calcium carbonate was constipating. Now a new study suggests that too much calcium just might do the body harm.

Nutritionists Embraced Calcium Supplements:

Many health professionals are skeptical about the value of supplements. They often advise their patients to eat a well-balanced diet and skip vitamin and mineral pills.

The exception has been calcium, sometimes with vitamin D. For decades, doctors have advised women (and some men) to take calcium supplements to ward off osteoporosis and bone fractures.

It seemed so logical. The National Institutes of Health (NIH) Osteoporosis and Related Bone Diseases National Resource Center states unequivocally:

“Inadequate calcium significantly contributes to the development of osteoporosis. Many published studies show that low calcium intake throughout life is associated with low bone mass and high fracture rates. National nutrition surveys have shown that most people are not getting the calcium they need to grow and maintain healthy bones.”

The experts recommend that women aged 51 to 70 should be taking in 1,200 mg of calcium daily. Men are told that they need 1,000 mg of calcium each day. To achieve such goals many people need calcium supplements.

Calcium Against Colorectal Cancer?

There was even some preliminary data suggesting that extra calcium might reduce the risk of colorectal cancers (Cochrane Database of Systematic Reviews, Jan. 23, 2008).

How Good is Extra Calcium?

After further study, however, the idea that calcium could prevent either osteoporosis or colon cancer has not held up. A recent meta-analysis published in JAMA did not find evidence that calcium supplements reduce the risk of hip fractures (JAMA, Dec. 26, 2017). This was a large review. It involved 33 randomized clinical trials and over 50,000 participants. The heretical conclusion:

“In this meta-analysis of randomized clinical trials, the use of supplements that included calcium, vitamin D, or both compared with placebo or no treatment was not associated with a lower risk of fractures among community-dwelling older adults. These findings do not support the routine use of these supplements in community-dwelling older people.”

Now, the notion that calcium protects against colon polyps has also been upended. A gold-standard, randomized controlled trial of more than 2000 people has just been published (Gut, March 1, 2018).

Unexpected Calcium Side Effects:

This study included more than 2,000 middle-aged Americans at high risk of polyps because they had already had one or more discovered during a colonoscopy. These volunteers were randomly assigned to take 1200 mg of calcium, 1000 IU of vitamin D3, both or neither for at least three years. Then they had another colonoscopy to look for polyps. At that point, the scientists saw no effect.

The investigators also collected data on polyps found after the treatment had stopped. That is when they discovered that the supplements increased the likelihood of precancerous polyps. Calcium alone raised the risk 2.65 times, while calcium with vitamin D made people 3.8 times more likely to develop polyps six to eight years after starting supplementation.

The authors of the study point out that both women and smokers were at higher risk of polyps when they took supplemental calcium. As a result, doctors might want to change their advice.

It no longer seems prudent to urge all women to take extra calcium and vitamin D “just in case.” Those who have already had a polyp and those who smoke may need to be particularly cautious about taking such supplements.

Calcium Side Effects and the Heart

In addition to the colorectal polyp controversy, there has been great uncertainty about whether calcium pills are safe for the heart and arteries. The Nurses’ Health Study, with 74,245 women observed over 24 years did not find any risk (Osteoporosis International, Aug. 2014).

Data from the Women’s Health Initiative, however, indicate a modest cardiovascular risk associated with calcium supplements with or without vitamin D (BMJ, April 19, 2011).

A prior analysis in BMJ (July 29, 2010) of 15 trials and more than 8,000 participants concluded:

“Calcium supplements (without coadministered vitamin D) are associated with an increased risk of myocardial infarction [heart attack]. As calcium supplements are widely used these modest increases in risk of cardiovascular disease might translate into a large burden of disease in the population. A reassessment of the role of calcium supplements in the management of osteoporosis is warranted.”

People’s Pharmacy Perspective:

Calcium side effects such as constipation are not considered worrisome. But our readers beg to differ. One shared this story:

“I know the desperation some of your readers feel about constipation because I suffered the same problem for years. Those who haven’t experienced this problem have no idea of its severity.

“I tried increasing fiber and fluids to no avail. I became convinced that the constipation was related to my medication. Over a period of time, by the process of trial and error, I narrowed it down to a calcium supplement I had been taking for years.

“I haven’t taken any calcium since then, and I haven’t had the problem either. I hope this information will help someone else.”

E.N. shared a similar story:

“Had the same problem. I was taking Tums for the calcium for about 2 years. I also took magnesium daily along with cooked greens and apples and bran type cereal daily. Made no difference. The calcium overcame all that and I came very close to having an impacted bowel. I stopped the Tums….have not had the problem since.”

More Serious Calcium Side Effects:

Now that we have data about calcium supplementation and colon polyps and vascular complications, we may want to rethink the reflex recommendation that everyone over 51 should be taking a calcium supplement.

Perhaps calcium supplements are not a great back-up plan to make up for inadequate dietary intake. Instead, people may need to concentrate on getting calcium from their food choices. So far no one has linked constipation, polyps or heart attacks to foods containing calcium.

What Foods are High in Calcium?

While everyone knows that milk is a good source of calcium, many older people don’t drink milk. They might consider yogurt, mozzarella or Cheddar cheese, or they might turn to tofu, turnip greens, collards, kale or bok choy.

Canned salmon or sardines, with the bones, are also good food sources of calcium and provide some vitamin D as well. Soybeans, white beans, sesame seeds and almonds can also help supply dietary calcium.

With careful attention to menu planning, people can be confident they are getting the calcium they need. They won’t have to run even modest risks of colon polyps or calcified plaque from taking calcium pills.

Want to learn more about other ways to prevent osteoporosis and fractures? Our radio show # 752 titled Bone Vitality is free. It features Walter Willett, MD, DrPH, one of the world’s foremost nutrition experts and epidemiologists. He is at Harvard’s School of Public Health. The MP3 download is FREE! Do not be confused by the $9.99 price for the CD. Where it says Choose CD or MP3 Version click on the downward arrow to select the FREE MP3 version. The price turns to $0.00 instantly.

Another freebie that is worth listening to is more recent. Show # 1093 is titled “How to Keep your Bones Strong.” It too is free. You can stream the audio by just clicking on the green arrow at in the black box at the top of the page or select the free MP3 version at the bottom of this page.

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  1. Carol

    I have nodules on my thyroid it started with one small now I
    have a second one large and I need biopsy. I started taking
    D3 1000mg over year ago. Since I have weakness in my muscles,
    joint pain,and the two growths. Does D3 cause this? I also
    take cold pressed primrose oil 500mg a day which I have taken
    many years with no problem. Was diagnosed with hoshimoto

  2. Helen

    I have hypothyroidism for which I take thyroid medication (NatureThroid), half dose in morning, half dose late afternoon. I am a regular coffee drinker. And I have increased my calcium intake, via milk, to deal with osteoporosis. I used to take calcium supplements, but no more. I am not convinced calcium carbonate or calcium citrate are effectively absorbed by the body to deal with osteoporosis. I take my thyroid medication 4 hours before any milk because milk interferes with absorption of thyroid medication. I also do not drink coffee within an hour before or after drinking milk because caffeine interferes with absorption of milk, hence my osteoporosis. I’d have a cup of coffee followed by cereal and milk, but the milk was not being absorbed because it was taken too close to the coffee.

    So, my daily regimen now is: First half of Thyroid medication first thing in the morning. One-half to an hour later a mug (12 oz.) of coffee; enough time to make sure caffeine does not interfere with thyroid medication. Four hours after taking the thyroid medication, I’ll drink 8-12 oz of milk (the body can only absorb 500 mg of milk at one time). I often have another mug of coffee mid-afternoon, an hour or two after drinking the milk, no sooner. Then four hours after the milk I’ll take my 2nd half dose of thyroid medication. If the timing is right, I’ll have some more milk before I go to bed.

    My next bone density test should tell how effective this is working out, which is a year away.

  3. Pat

    I would add that weight bearing exercise such as fast walking, stairs, vacuuming, climbing hills, walking in sand, pushing a lawnmower etc. help to prevent osteoporosis. Keep it more gentle but still weight bearing if you are already diagnosed. Cannot recommend stepping programs because I think they are too hard on the knees.

  4. Judith
    Hillsborough NC

    After reading the above article, I am a bit concerned about taking vitamin D3. Several years ago after my bone density scan, the doc suggested I increase my dose to at least 4000iu to 6000iu daily. I have been taking 4000iu. I get my calcium from my diet due to side effects with supplements. I will be interested to see my density scan results in a few weeks. However, should I be more concerned now that these results have been posted? Maybe stop the D3 all together? I also recently read that D3 can be good for dementia. Of course, these days, folks are pushing lots of things for dementia. Thanks for your thoughts.

  5. Anne

    I also stopped taking calcium. I take Vitamin D and a multi-vitamin ( which contains very little calcium.) I try to eat foods with it instead. Even with vitamins, my doctor says that if you are eating a well-balanced diet, you should not need to take vitamins.

  6. Kate
    Waynesville, NC

    Forty years ago I worked with a PhD nutritioninst who said never take calcium without also supplementing with magnesium. I’ve cringed ever since when docs recommend tums. And they are the least absorbable form of calcium! Now we know calcium, mag, vit D3, and vit K2 are all necessary to prevent calcium from depositing in soft tissue and deliver it where it needs to go. I’ve also learned in the last few years that calcium and magnesium may each be better absorbed if taken separately. What else will we discover in another few years? I prefer getting cal. from food and supplementing the rest – except vit D during the summer when I spend the required time outdoors. As nursing students, we sat in on the 3 hours that were the sum total of the med students’ education on nutrition. Best to get nutritional advice from someone who is better-versed. The Graedons are a good place to start

  7. Lisa

    I have always wondered about the calcium in nut milks. I believe it is the same form as supplements (calcium carbonate). Is that the same as taking a supplement? Is the calcium in cows milk any more desirable?

  8. Cindy Black
    Seattle, WA

    For several years now, I’ve been hearing that calcium supplements are NOT ADVISED for post menopausal women like me — for all sorts of reasons. Every time I bring this up in conversation, like at a healthfood store, they immediately agree that I shouldn’t take calcium. I can’t remember all the reasons, but heart problems were one. I can’t believe anybody is still taking calcium supplements anymore! I take Vitamin K and Vitamin D (along with a lot of other stuff), and I have great bones at 70.

  9. Fran
    West Palm Beach, FL

    Do these studies take into account the role of Vitamin K2? I understand that without a sufficient quantity of K2, calcium ends up in the wrong places in our bodies, such as our arteries, and perhaps the colon, and not to our bones. I’d appreciate your addressing how Vitamin K2 affects the results of our calcium intake.

  10. Joyce B.
    San Antonio, Texas

    My question is are there any side effects or complications to suddenly stop taking the calcium supplement after taking it daily for literally over 20 years?

  11. Linda

    My aunt fell and broke her ankle at age 68. She was prescribed calcium supplements during recuperation. Then at home she developed a severe intestinal blockage that resulted in her having emergency surgery and a colostomy. She died from complications at age 70. Beware!!

  12. Larry M
    Raleigh, NC

    What is with these people and their simplistic solutions?

    “Your bone density is low. Bones are calcium. Eat lots of calcium and your bones will be denser. No, we didn’t bother to test it. Isn’t it obvious?”

    “You have too much cholesterol. Cholesterol is in beefsteak, milk, cheese, and butter. Don’t eat those things and your cholesterol will go down. No, we didn’t consider that cattle are mammals, that cattle eat only a grain diet, that cattle must manufacture cholesterol, or that humans are also mammals and also manufacture cholesterol. Just stop eating those things. Isn’t it obvious?”

    Doesn’t anyone think these things through anymore?

  13. Therese Melancon

    It’s funny that Calcium/Magnesium causes constipation to some people. For me it’s just the opposite. My GI doctor said to quit taking it and when I did I quit having diarrhea every day.

  14. Patricia

    What about eating natto? – it may not be everybody’s cup of tea* but I understand it ensures that the calcium goes where it’s needed (to your bones) and not to your arteries and other nasty places. This has all been demonstrated before – please see
    *Taking vitamin K2 (which is abundant in natto but not in much else) may do the trick if you can’t hack the natto

  15. EmilyB
    Chicago IL

    I’m currently taking 60 mg of calcium 2X daily along with other vitamins & minerals to treat a minor health problem. I am a long time user of a diuretic, triamterene, for HBP. Starting 4 years I’ve had a series of minor health issues involving my mouth. It began with burning mouth syndrome. After a lot of research & trials & errors which included seeing my doctor, dentist & an oral surgeon, I determined it was a B12 & magnesium deficiency. Later on, I developed blisters inside my mouth due to a whitening toothpaste. I changed toothpastes. It happened again. After the latest incident & more research, I learned that diuretics cause loss of vitamins & minerals. So I’m on a major vitamin & mineral consumption project right now to heal my mouth. I switched to a detergent free toothpaste. I’m also using an over the counter mouth rinse for healing mouth sores which is helping. I had to discontinue all acid containing foods like pickles and lemons. My mouth is healing. When the vitamins & minerals are used up, I’ll reassess the situation. Extreme vitamin and mineral therapies are going to be required for diuretic users in situations like mine.

  16. Tina
    North Palm Beach, FL

    Your article only refers to calcium carbonate. I’m curious as to what side effects a whole food plant formula based calcium might have.
    I’ve been on a regimen of a popular raw, whole plant based, calcium with 756mgs calcium and 1600 mgs of D3 for years with no side effects thus far. It also contains magnesium derived from algae and Dead Sea minerals, and organic fruits and vegetables. It’s about as natural as any supplement can be.

    Your thoughts are greatly appreciated!

  17. susan

    I, too, took calcium supplements for about 8 years or so. All of a sudden I was suffering from terrible pain in both thighs. The spasms were like contractions. It was just awful. I could hardly walk due to them and was exhausted. One day I decided to quit them and within a few days no more pains in my thighs. I eat plenty of foods with calcium and feel I was getting too much. Not sure but going off them worked for me.

  18. Alicia
    Abq., NM

    I started taking Calcium a long time ago because it seemed to relax me so I could sleep. Unfortunately, even with Vit. D, I developed bone spurs in my feet – 3 on one foot alone! I stopped the calcium and began taking Magnesium instead and have not had any more spurs. I get my calcium for natural sources. There is no need for supplementation.

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