What role calcium supplements?

A frequent question in the Track Your Plaque program is whether taking calcium supplements to reduce risk for osteoporosis adds to calcium in arteries and raises CT heart scan scores.

No, calcium supplementation does not add to coronary calcium. Thankfully, there is some wisdom to calcium metabolism. Calcium deposition or resorption is under independent local control in bone, as it is in the artery wall. Taking calcium has no effect on calcium deposition in your coronary arteries.

However, there's a lot more to it. Taking calcium has only a modest effect on bone health. Most women can only hope to slow or stop calcium loss from bone by taking calcium supplements. Calcium supplements do not increase bone calcium. The reason why calcium supplementation works at all is, when calcium is absorbed into the blood, it provides a feedback signal to the parathyroid gland to shut down parathyroid hormone production, the hormone responsible for extracting calcium from bone. But the calcium itself does not end up deposited in bone.

Likewise, calcium supplements have essentially no effect on the artery wall. But vitamin D controls calcium absorption and, curiously, appears to exert a dramatic effect on calcium depostion in coronary arteries. In fact, I would credit vitamin D as among the most important factors in regulating arterial health that I've encountered in a long time.

Thus, bone health and arterial health do indeed intersect via calcium, but not through calcium supplements. Instead, the control exerted by vitamin D connects the seemingly unconnected processes.

Vitamin K2 provides another unexpected juxtaposition of the two processes. Deficiency of K2, which is proving to be a lot more common than previously thought, permits an enzyme in bone to exert unrestrained calcium extraction. Deficiency of K2 in artery walls allow another enzyme to deposit calcium and grow plaque without restraint. Yet another intersection between bone health and coronary health that involves calcium, but as a passive participant.

Stay tuned for a comprehensive Track Your Plaque Special Report on these topics coming in the next couple of weeks. I'm very excited about the emerging appreciation of calcium as an active ingredient in plaque, not a dumb, passive marker as previously thought. Vitamins D3 and K2 are among the keys to this phenomenon.

Comments (8) -

  • JT

    7/22/2007 12:34:00 PM |

    I'm probably living proof that eating or taking calcium does not cause a high heart scan score.  

    For around 18 years I suffered from a crippling gut problem.  During that time I was advised to avoid milk products along with high fiber.  Milk was avoided because of lactose intolerance and another effect I noticed it had on the gut.   Calcium rich vegetables were not eaten in much quantity due to fiber causing my gut problem to become worse and more painful.  Early on I tried taking calcium tablets but they caused a great deal of gut problems too so that was stopped.  

    Basically my body was calcium deficient for close to 2 decades.        

    It was only after I figured out my gut problem was food related - a food allergy - that I began eating fiber calcium rich foods along with cheese again.  It was also around this time that I had a heart scan.  My score is in the top 90% for my age.  From blood testing it appears my plaque build up came from eating a sugar rich / low fiber diet and not eating too much calcium.

  • Anne

    7/22/2007 5:38:00 PM |

    Is there a test for K2 deficiency?

    What is the best source of K2?

  • Dr. Davis

    7/23/2007 12:00:00 AM |

    To my knowledge, no clinically available measure of K2 adequacy is yet available. The best source is arguable, but we're gravitating towards supplements that supply the MK-7 form until the data clarify.

  • DrSwanson.com

    1/8/2010 9:21:38 PM |

    Dr Davis,
    Thank you for your comments. You state that supplemental calcium does not cause artery calcification, explaining there are different mechanisms in bone vs. arteries, etc. This may not be the case however.  A recent study has shown that calcium supplementation might very well increase vascular events (e.g. heart attack or stroke) in elderly women. According to the studies lead author the findings were surprising and robust.
    1. Bollard MJ, et al. Vascular events in healthy older women receiving calcium supplementation: randomized controlled trial.
    2. Medscape CME/CE 1/24/08
    ref: British Med. J. 1/15/2008

    These calcium concerns can be added to other studies linking excess calcium (esp. calcium citrate) to small vessel calcification in the brain, and others showing increased aluminum levels when co-ingested with sources of aluminum hydroxide, such as antacids. Also noted here is calcium citrate is up to .25 to 2.5 times more absorbed and bioavailable than calcium carbonate. Then a more prudent dose recommendation becomes necessary. Ours is to limit the dosage below the daily value (DV) for most post-menopausal women. The DV is based mostly from lessor absorbed (esp. on an empty stomach) calcium carbonate studies.  
      In our clinic, the following calcium (citrate, or citrate/malate) supplementation guideline is given to postmenopausal women, and especially important for over age 65.
    1. Do not take calcium without vitamin D3 and vitamin K2 (MK-7), unless K is contraindicated because of warfarin / coumadin.
    2. Limit dosage to 600 mg per day, as unopposed with or without vitamin D. (e.g. a cal+D supplement)
    3. Limit dosage to maximum 1200 mg / day with the co-administration of vitamin D (dosage based on 25(OH)D testing) and vitamin K2 (MK-7a) 50-100 mcg /day.  
    4. Limit calcium (citrate)intake to 600-1000 mg / day (even with D+K) if known coronary artery disease is present or coronary calcium score elevated, or smoking.  
    5. If elevated coronary calcium score is elevated and the risk for CHD is high, individualize the vitamin K2 (MK7) dose upward as high as 300 mcg/day to attempt to reverse the calcification.
    6. Do not take aluminum hydroxide antacids, or any other sources of
    7.Related "bone up" caveats: Recognize that bone loss and CHD often co-exist in the same patient. Hip fracture risk is greatly increased with proton pump inhibitors (e.g. reflux meds). Consider natural alternatives to bisphosphonates and calcium+D only supplements.  e.g. The FOOT Plan (Fully Optimized Osteoporosis Therapy) using strontium citrate, potassium (citrate) alkalization,  vitamin D3/K2, omega-3 EPA/DHA, melatonin, and calcium /magnesium citrate. Far greater and faster bone density results occur in both spine and hip, with healthier bone architecture and geometry. And much healthier for the heart too!  

    Mark Swanson, ND

  • Jackie

    3/11/2010 9:23:28 PM |


    I was diagnosed with stage III-C uterine cancer about 4 years ago. A recent CT scan of the abdomen and pelvis revealed atherosclerotic disease. However, the same day I took the scan, I also took a Calcium Scoring test which revealed a good score of zero concerning the heart arteries.

    I ordered k2 supplements, but I am leery as to whether it would increase estrogen in my body because K2 is generally derived from fermented soy beans. When I was first diagnosed, one oncologist felt soy was ok, another oncologist plus my gynecologist suggested I steer clear of it. I just wonder what your opinion is on this matter. Also, would the fact the scan picked up atherosclerotic disease indicate it is in an advanced stage? Thank you.


  • buy jeans

    11/2/2010 9:17:33 PM |

    Thus, bone health and arterial health do indeed intersect via calcium, but not through calcium supplements. Instead, the control exerted by vitamin D connects the seemingly unconnected processes

  • Jack

    3/9/2011 3:43:19 PM |

    Chances are the calcium supplement you are taking now is a rock source of calcium. The label will say "calcium carbonate", which is nothing more than limestone. AlgaeCal Plus contains an organic, plant-sourced calcium form derived from a unique South American marine algae called Algas Calcareasâ„¢.

  • paul

    4/29/2011 6:25:25 AM |

    Calcium supplements helps strengthen your bones. You should always take them to maintain your strong bones.

    Lorna Vanderhaeghe products