How To Take Calcium So It Goes Into Your Bones, Not Your Arteries

Photo courtesy of Woodley Wonder Works


Calcium supplementation has been put under a microscope recently, with a lot of evidence turning up news that doesn’t inspire optimism that digesting chalk is going to help grandma’s chances of suffering from that tumble down the stairs.

In particular, Chris Kresser wrote an article basically stating that they’re no good at all.

The reasons are two-fold:

  1. Hey, grandma, don’t trip!    There were some meta-analyses put out recently that summarized the effect of calcium supplementation on bone density and found they had no effect.
  2. Strengthen your bones, get a stroke.  Large amounts of undigested calcium has a tendency to go into your arteries, not your bones.  This greatly increases your chances of dying from a heart attack.

So is that calcium pill doing harm or good?

Well……I think it depends.

He’s right that gorging on an all-you-can-eat buffet of calcium supplements and calcium fortified foods won’t do you any good if you don’t account for other nutritional factors.  But I do believe the fine doctor is overlooking some important points:

  • Bone turnover is slow.  Like, REALLY.    Specific bone tissues take about two years to regenerate themselves.  Your bone re-models itself completely every five years.  The average clinical trial is 60 days.  Measuring bone mineral density with a clinical trial is like timing the growth of grass on your lawn with a stop watch.  It’s no surprise lots of results show nothing.  That’s what you should expect.
  • There is no calcium fairy that magically sprinkles it into your skull.  It needs other nutrients to go into your connective tissue.  Specifically, vitamins D and K, and the minerals Magnesium and Phosphorus.  Most people have pseudo-deficiencies in D, K and Magnesium.  Without them your body won’t have the ability to make use of the calcium it has.  So the relevant question is, what effect does calcium have when you account for these other nutrients?


With that being said, what should our feelings rightfully be about taking tablet-ed seashells every morning?

Buckle up kids, it’s going to be a wild ride![amd-zlrecipe-recipe:9]

What Makes Calcium Work

As noted before, calcium has to work with other nutrients in the body in order to make its way into your bones.  If it doesn’t it really is just chalk!

Like everything else in your body, the calcium pathway is modified in some way by just about everything else.   But D, K, Magnesium and Phosphorus play an especially important role in shaping calcium’s role in your body.

Vitamin D – The Little Steroid That Could

There is no element of calcium metabolism that isn’t shaped by vitamin D.  From when it enters your stomach, circulates through your bloodstream, goes into your bones, and gets filtered out through your kidneys…….it’s all shaped by the Big D.


Your body has to have adequate levels of vitamin D to absorb calcium!  

Calcium absorption with calcium is very sensitive and does a lot with a little.  Without D it practically turns off.

That’s because your body absorbs calcium in two ways – one active, the other passive.

The active way needs vitamin D, is very sensitive, and its gas tank is filled up quickly.   The passive method of absorption is “dumb” – it just allows calcium to diffuse across your intestine and never shuts off.

The vitamin D channel absorbs close to 100% of the calcium you digest up to about 200 mg, and 80% up to 300 mg.  After that it turns off.  Any calcium above this amount is absorbed through the passive process, where the absorption rate falls off a cliff to 5-10%.

For this reason someone who’s saturated with vitamin D will absorb twice as much calcium as someone who’s vitamin D gas tank is running on empty.

If a study uses someone with low levels of vitamin D, pumping them full of calcium salt by the kilo won’t have an effect because it’s all being absorbed through your body’s passive digestive process………and paying a buck for every 5 cents of calcium it gets.

Talking about the effects of calcium without mention of your vitamin D levels has no meaning.

Okay, so what’s the vitamin D status of Average Joe?

Healthy levels of vitamin D are 50 ng/L and above.  The “best” levels might be closer to 80 ng/L (these are  the levels attained by life guards and people who live close to the equator).  Most people have vitamin D levels around 15-25 ng/L.  At this level calcium absorption is seriously impaired.

Well, obviously a calcium supplement won’t do any good if your body can’t use it!

In the meta-analysis linked to above, the total results did not show any correlation between calcium intake and bone density, but there was a significant impact when calcium was taken with vitamin D.  See here also.

Vitamin K – Just Say No To Calcium In Your Arteries!

Calcium eventually makes its way into your arteries if it doesn’t go into your bones.  That’s not good.  People with high levels of arterial calcification are 10x more likely to suffer from a heart attack than people that don’t.

This is why high levels of calcium intake can lead to increased risk for coronary heart disease.  Your body uses vitamin K to modify a protein called MGP that prevents calcium from building up in your veins and chokin’ off your ticker.  When mice are bred without MGP their arteries turn to chalk and die in 8 weeks.  Ouch!

A similar, albeit less dramatic effect has been observed in humans who have inadequate amounts of vitamin K.   (It would just be mean to deliberately kill people, so we do clinical studies instead).  People with calcified arteries that dose with a well absorbed form of vitamin K (mk-7) see a significant reduction in arterial calcification.

The study linked to in Chris Kresser’s article does not control for vitamin K levels.

As I’ve written before, there’s good reason to believe people have inadequate levels of vitamin K.  Current RDA’s are based on levels of activated blood clotting proteins. This doesn’t account for vitamin K’s role in slow turnover tissue like bone and enamel.

In studies with mice you can regularly feed them inadequate levels of vitamin K but still have their blood work turn out normal because it’s being leeched from bone and teeth.

Not surprisingly, vitamin K also improves bone mineral density, especially when taken with vitamin D.

When I read about the dangers of calcium supplementation, I wonder to myself if it’s secretly a proxy for inadequate levels of vitamin K.

Magnesium – It Keeps Calcium In Its Place

Inside your bone calcium complexes with phosphate to create shiny  crystals.  The outside of them are plated with magnesium.

Magnesium is easily removed during the food production process and most people have a pseudo-deficiency.

In addition to helping your bone crystals, magnesium blocks calcium from going to places it shouldn’t.  Magnesium likes to rest inside your cells, calcium on the outside.  If you’re deficient in magnesium, calcium will drift in, preventing it from settling in your bone.

Magnesium is also a co-factor for a hormone called PTH, which is important for regulating bone formation and very sensitive to nutrient levels.

Mice that are starved of magnesium develop pretty severe osteoporosis.  Magnesium taken with calcium has a better effect on bone density than calcium alone…..that shouldn’t be a surprise.


Calcium leaves your intestine complexed to phosphorus, and bone itself is made up of calcium-phosphorus crystals (aka, hydroxyapatite).

Unlike the first three nutrients listed, you don’t need to supplement with phosphorus.


It’s abundant in the diet already, and easily absorbed at practically any amount.  Any food high in protein will have a lot of phosphorus, and your body readily absorbs 60-70% of the phosphorus you eat, regardless of the amount.

Important?  Yes.  Something you ought to worry about?  No.

Necessary? Probably Not…….Unless You’re Old

If you have adequate levels of D, K and Mg you don’t need a calcium supplement.  You’re better off with 500 mg of daily calcium and adequate amounts of these three than taking 1,000 mg and living with the pseudo-deficiencies most people have in them.

But most of the “dangers” or ineffectiveness of calcium supplements are actually a byproduct of not using them in conjunction with these nutrients.  When you correct for their presence the benefits of calcium supplements seem legitimate, albeit modest.

So am I going to drop $12 for a bottle of calcium citrate?  Nope.  I’ll make sure I crisp in the NYC smog for my vitamin D (where I’m currently located), eat lots of greens (for my Mg), and eat my weekly helping of liver (vitamin K).

But if grandma Newman wanders whether or not she ought to keep using hers, I’ll give her my blessings, so long as she takes them the right way.


Long, Samantha, et. al. “Role of Cellular Magnesium in Health and Human Disease”

Rock, E, et. al. “Dietary magnesium deficiency in rats enhances free radical production in skeletal muscle.”

Bischoff-Ferrari, et. al. “Calcium intake and hip fracture risk in men and women: a meta-analysis of prospective cohort studies and randomized controlled trials”

Li, Kuanrong, et. al.  “Associations of dietary calcium intake and calcium supplementation with myocardial infarction and stroke risk and overall cardiovascular mortality in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition study”

Bruce W. Hollis “Circulating 25-Hydroxyvitamin D Levels Indicative of Vitamin D Sufficiency: Implications for Establishing a New Effective Dietary Intake Recommendation for Vitamin D”

Rock, E, et. al. “Dietary magnesium deficiency in rats enhances free radical production in skeletal muscle.”

Chatroue, Martin, et. al. “Role of vitamin K-dependent proteins in the arterial vessel wall”

Schurgers, Leon, et. al. “Matrix Gla-protein: The calcification inhibitor in need of vitamin K”

Calcium and Magnesium in Public Drinking Water – Public Health Significance

19 thoughts on “How To Take Calcium So It Goes Into Your Bones, Not Your Arteries”

  1. Okay, so if you need all those and not that much calcium wouldn’t it just make sense to take them and leave calcium alone?

    I don’t get your point about the article.

    I personally take NOW Foods magnesium and can usually tell when I’ve skipped it for a while. I get low energy levels if I skip it for a while


    1. Ray,

      I basically agree that calcium pills are not necessary for the majority of people, and given the makeup of most people’s diets, D, K and magnesium are much more useful.

      But my point was that calcium supplementation, in addition to these three nutrients, has a positive effect independently when taken with them.


  2. The supplement industry, like most other industries, is a total sham that exists only to prey on gullible consumers and manipulate their own delusions about mind and body for a shady profit.

    I find them, including the many pedaled on this blog, to be utterly worthless and not deserving of people’s money.


      1. I’m not a grump. I just understand what’s valuable and what’s a marketing con. Studies done on the composition of dietary supplements repeatedly show that most of them are degraded, and clinical trials routinely show their effects are either modest or non-existent.

        You’re wasting your money.


      2. Well I’ve been taking magnesium and fish oil for 3 years now and have seen my LDL and blood pressure go down during that time, to the point that I’m almost off medication.

        When I don’t take them I feel lethargic and my numbers tick up. Is that an accident? Just because you don’t like them doesn’t mean they don’t go good for others.


      3. Good for you and your magnesium pills. I’m sure they make you feel better, but the truth is that it’s most likely placebo and nothing more.


  3. My mother takes calcium and vitamin D in addition to glucosamine/MSM and kava extract for stress. She says it helps her and thinks it helps her move around. She was diagnosed with osteoporosis 5 years ago and has been losing bone mineral density for years now.

    I’m going to look into vitamin K too.

    Does anyone know of any good brands?


    1. I hate to be the one to break the news, but you and your mother might want to reconsider how to spend her hard earned retirement dollars on something other than sawdust capsules that are likely doing no good at all. I recommend something that’ll have a more immediate effect, like a good massage.

      At least if you get one of those you can tell right away whether or not it’s worth a damn.


      1. Well I’m sorry but I’m going to trust my ND that I’ve been working with for 5 years more than a stranger on the internet like you.

        Maybe you should get a massage, it might calm you down.


  4. The RDA’s for minerals are all overrated. All minerals have an active transport process that’s very sensitive and gets saturated quickly. With a nutrient dense diet your body can make full use of it and doesn’t have much of a need for the passive transport.

    The problem is that most people have micronutrient deficiencies of some sort that prohibits them from making use of it so they have to use the passive transport process to get the levels they need, which jacks the RDA’s way up.

    If you’re healthy you only need 1/2 of what they recommend.


  5. If you get a magnesium supplement, be sure you get a good one made from the highly bioavailable magnesium chloride. Most magnesium supplements you get in stores are made from magnesium oxide which is almost completely worthless. Don’t fall for it!


  6. My blood calcium is fine yet I have osteoporosis. That makes sense that blood calcium would be in the normal range while it’s sucking the life out of my bones.


  7. 1.Yes you can have blood Calcium tested and the result is normal, even though the calcium in your blood came there by taking it from your bones.
    2. An affordable scan called DEXA will show if your bones are becoming less dense. In Australia, where I am, this scan is recommended after age 70 for males. I had mine done early at age 65, after a fracture made me suspicious. My suspicion was “rewarded” – I have osteoporosis at an advanced level so that fracture is likely.
    3. I use the D,K, Mg trio of supplements and will have series scans to see if there is improvement. The amount of improvement is not so important as the trend toward increase in bone density. Small improvements can be quantified.
    4. Weight bearing exercises are also shown to increase bone density independent of supplements.
    5. But I cannot understand why people don’t have the scan in their 40’s even if only to get a baseline. My scan was much too late.
    6. Now I am really challenged by the pending threat of fractures, but remain very active with good posture. I walk ten kms a day, and do weights and stretches. My calcium supplement is about half of the RDA, but there is abundant Calcium in my food.
    7. My fractures did heal, despite my porous bones.
    8. Supplements are part of being positive.
    9. There is no percentage in being relaxed and vitamin deficient.


  8. Dear readers…

    It’s vitamin K2, not K1. People can live on maccas and still get enough K1. K2 comes from fermented vegetables esp. natto (fermented soy beans). Natto is the highest form of mk7. Liver, esp. goose liver is high in mk4. Mk4 is a lesser quality form of vitamin K2.

    Calcium combines with vitamin D and will float around the blood stream. Vitamin K2 transports calcium (that is binded with vitamin D), to either send it to the bones, remove it from arteries or produce apoptosis. There are 3, K2 dependent proteins. I forget their names. 1 takes it to the bones. Another removes it from the arteries and the third produces apoptosis. Apoptosis is where this (K2-triggered) protein travels through the body looking for deformed, damaged or mutated cells. This protein either repairs the cell or destroys and breaks down the cell and removes it from the body. Mutated cells such as cancer.

    If you live close to the equator, ten minutes of sunlight, on half of your face, per day is an adequate amount of vitamin D.

    Animal protein sucks calcium from the bones to neutralize the acid (sulphur and phosphorus), before it passes through the liver. The kidneys combine this calcium (sucked from your skeleton) with the acid (from animal protein such as liver) to neutralize the acid before it reaches the liver. Any left over calcium in the kidneys can cause stones…calcium stones…kidney stones.

    Dairy products are animal proteins and you can lose up to 60% of the calcium consumed when you consume these.

    Pro biotics are from the soil. Pre biotics are from plant foods. The lower gut forms lactobacillus from pre biotics. Or you can ingest lactobacillus in the form of MK7 (fermented plants) or eat unpoisoned healthy soil. MK4 works but not as well. MK4 is from high cholesterol animal products such as liver, especially goose liver, and from living cheese such as brie. Yoghurt is not a good form of pro biotic. The quantities and qualities are too unreliable. Good quality capsules are best.with at least 25000 bacteria. Refrigerated capsules tend to be more reliable.

    The main point of contention here is that the human body was not designed to eat animals…period. If you are a proper vegan (ie. you eat an organic whole plant foods diet)…you do not need to read this article.

    You get calcium and every nutrients from whole plant foods. You get vitamin D from the sun (or supplementation if needed). You get pre biotics from plant foods. You get pro biotics from the organic soil on your organic foods, the way nature intended…or you can supplement with capsules (ask a pharmacist which ones).

    The biggest thing is don’t eat ANY animal protein! If you do…no more than 5% according to every study done on this.

    Watch ‘Forks Over Knives’ and tune into ‘The Real Truth About Health’ conference on google search.

    Dr Colin Campbell. Dr Caldwell Esselstyn. Dr Joel Furhman. Dr Hans Dhiel. Dr Brian Clements. Dr Pam Popper. Brenda Davis RD and 75 other world renowned doctors all with peer reviewed work on the one website.

    You can also google the studies that are being done with vitamin K2


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