Calcium Supplementation to Help Prevent Bone Loss

Calcium is essential for optimal bone health throughout your life. Although diet is the best way to get calcium, supplements may be required if your diet falls short. Before you consider calcium supplements, be sure you understand how much calcium you need, the pros and cons of calcium supplements, and which type of supplement to choose.

With respect to calcium supplements, the four most commonly available sources are listed below. As one can see, the percentage of each that can be assimilated by the digestive system and incorporated into the bone is highly variable. Moreover, while insufficient calcium intake is a serious problem, recent research indicates an overload of calcium caused by drinking too much milk, along with taking calcium supplements or antacids, can cause a host of serious side effects. These include: hypercalcemia, (a shift in the body's acid/base balance towards alkaline), calcinosis and nephrocalcinosis, (calcium deposits in the tissues and kidneys), kidney stones, plaque in the arteries, and an increased risk of heart attack, stroke, and kidney disease.

• Calcium carbonate 40 percent elemental calcium

• Calcium citrate 21 percent elemental calcium

• Calcium gluconate 9 percent elemental calcium

• Calcium lactate 13 percent elemental calcium

The recommended daily allowance (RDA) of calcium for an adult, published by the Food and Nutrition Board (FNB) at the Institute of Medicine of the National Academies, is 1000–1200 mg (1200 mg for age 70 and older) and based on the latest research, it is best to get as much calcium as possible from natural food sources while minimizing supplemental calcium - especially calcium carbonate. Interestingly, the number the RDA is based on, (the number that really matters), is how much calcium you absorb, not how much you eat. The average adult needs 300-400 mg of calcium that can be readily metabolized and used to satisfy the body’s calcium requirements.

The following is the very short list of high calcium food items that have been tested for bioavailability. Note: Minor sources have been omitted from this list, as well as fortified foods (such as calcium fortified orange juice, calcium set tofu, calcium fortified soy beverage, etc.), as they include nothing more than the basic food item with supplemental calcium added.

Food Serving Size Calcium absorbed per serving

Collard greens 1 cup cooked 173 mg

Canned salmon (6 oz with bones) 6-ounce serving 114 mg

Turnip greens 1 cup cooked 102 mg

Milk, Lactaid, yogurt 1 cup 96 mg

Cheese (hard such as cheddar) 1 ½ oz 97 mg

Sardines (with bones) 1 can (3.75oz) 95 mg

Bok choi 1 cup cooked 69 mg

Broccoli 1 cup cooked 57 mg

Kale 1 cup cooked 46 mg

Mineral water 20oz bottle 41 mg

Mustard greens 1 cup cooked 42 mg

Chinese spinach ½ cup 29 mg

Almonds 1/4 cup 22 mg

Beans (white) 4 oz 25 mg

Beans (pinto) 4 oz 15 mg

Beans (red) 4 oz 10 mg

Whole wheat bread 1 slice 17 mg

A glance at this list makes it immediately apparent that without milk and/or milk products it is very difficult to meet the daily requirement for bioavailable calcium without relying heavily on supplements. This, however, is complicated by the fact that approximately 25% of Americans are lactose intolerant. Fortunately, Lactaid can be substituted for milk, lactose free yogurt is readily available, and many lactose intolerant people can eat small portions of hard cheeses without a problem. The reason being that most of the lactose in cheese is converted to lactic acid when the milk and/or cream is cultured, and more drains off with the whey during the aging process.

Another little known fact is that green leafy vegetables, which are very rich in calcium, often contain phytates and/or oxylates. These “antinutrients” bind to the calcium in the cells of the plant and block bioavailability. A good example is spinach, which contains 115mg of calcium per ½ cup, but provides only 6mg that can be metabolized and used to meet the body’s calcium requirements. Furthermore, when these foods are included with a meal, the phytates and oxylates they contain bind with the calcium in other food items you eat and block its absorption as well.

Vegetables high in oxylates include: carrots, spinach, okra, kale, chard, beet greens, rhubarb, collard greens, broccoli rabe, turnip greens, and Brussels sprouts. From the above chart, however, it is obvious that collard greens and turnip greens are so high in calcium that the negative impact of the oxylates on other food items is more than offset by their high bioavailable calcium content.

Foods high in phytates include: whole grains, nuts, seeds, beans, and legumes; with beans being the biggest concern. Fortunately, the phytates in whole wheat bread are removed during leavening, so this staple remains both a healthy food and a good source of calcium.

Lastly, it has been shown that vitamin D3, magnesium, and vitamin K2 work either synergistically with calcium, or contribute to its absorption.

Based on the aforementioned research, eating a nutritious diet, plus the following suggested supplementation should help prevent osteoporosis and maintain strong healthy bones, nerves, and muscles.

cup of milk or yogurt, (either regular or lactose free) 96 mg

2 ounces of low fat hard cheese 129 mg

1 can of sardines, 1 serving salmon, or a third portion of dairy 95 mg

400mg of calcium citrate (21% elemental calcium) 84 mg

Total 404 mg

Significantly, once the daily calcium requirement has been met, (with the above suggestion, or any variation), antinutrient containing green vegetables, which taste good, contain beneficial fiber, vitamins, minerals, and disease fighting phytochemicals can be enjoyed with meals.

Lastly, it is recommended that from 1500 - 2000 mg vitamin D3, 200 mcg vitamin K2, and 500mg Magnesium be taken daily to augment the activity and/or absorption of calcium.

26 Replies

  • Thank you Admiral06, I'm sure it will be of use to the newcomers. And for us old-timers, it doesn't hurt to be reminded now and again!

  • Thanks polkadotcom, I wanted to refer to my previous post, but unfortunately I could not find it in the archives. Two of my practitioners are now passing this document along to patients.

  • Very informative, Admiral06!

    I have read, although I can't now find the reference, that calcium hydroxyapatite may be more easily absorbed by people on prednisone. The supplement is made from New Zealand cattle guaranteed to be KJD free. In fact I just found a reference that hydroxyapatite may be contraindicated for people on corticosteroids, so who knows? It's the kind I've been taking for the past fourteen months or so. Before that I took calcium citrate. Bone density measurably improved.

  • When I researched this form of calcium while developing my personal supplementation plan, I found that tiny crystals of hydroxyapatite sometimes form in or around joints and cause inflammation of joints tendons and ligaments. This has been referred to as hydroxyapatite crystal disease. Atlhough hydroxyapatite supplements have not been directly linked to this disease, it has been considered a possibility. I chose instead to get my calcium from natural foods with small supplements of calcium citrate.

  • Hydroxyapatite is what our bones are made of. I think the possibility of these crystals forming is another reason to take Vitamin K2, so the calcium goes to the right place!

    "The main component of bone is bone matrix, which is a mixture of a fibrous protein called collagen and carbonated hydroxyapatite, an inorganic compound mostly made of calcium and phosphate. The combination of fibrous collagen and crystallized calcium makes bones hard and rigid and adds tensile strength."

  • HeronNS, I get almost all of my calcium from foods and take calcium citrate supplements only when away from home. Several credible sources have found calcium from foods to be better and safer than any available form of supplementation.

    The Ossein Hydroxyapatite form seems very interesting, but the trials that have been conducted compared it against calcium carbonate which has less bone preserving effect than the citrate form. In these trials it provided a 1% advantage over the carbonate salt which is a significant difference.

    The reason for a calcium and vitamin D regimen and its limitations are as follows:

    Steroid therapy decreases intestinal calcium absorption and increases renal calcium excretion. This can lead to a calcium deficiency which is a major risk for bone loss. Supplementation with calcium and vitamin D can prevent this potential problem, but is “generally” not enough to prevent bone loss and fractures when the steroid dose is over approximately 7.5 mg for 3 months or longer.

    Unfortunately, “generally” was not quantified, but based on unique and unidentified metabolic factors, some fortunate individuals enjoy a good clinical response from supplementation alone.


    Interestingly, calcium and vitamin D given for 2 years significantly prevented bone loss at the lumbar spine and forearm, but thinning continued at the at the neck of the femur (near the ball of the hip socket) and the incidence of fractures was not significantly changed. When the dose fell below 6 mg, however, bone mass increased in the lumbar spine and trochanter, but the neck of the femur remained unchanged.

    In summary, taking supplements is a necessary first line measure to prevent osteoporosis, and while it has measurable benefits that can't be ignored, neither calcium hydroxyapatite nor any other form has been scientifically proven to prevent fractures.

  • Thank you Heron & Admiral for the nutritional info. I am interested in having a diet to satisfy what my body needs to help maintain good health and help PMR. While I eat broccoli, kale, & chard because they are 'good' for me, I am now aware of calcium absorption and antinutrients! Very complicated. And I need to factor in I take Calcichew with D3. Not sure which type of calcium this provides but I will have a look. I know K2 is 'good' for calcium absorption - we eat in Gouda where cows have been grass fed. So much info to absorb, but fascinating!

  • Spinach has never been a good source of micronutrients, in spite of Popeye. And I think the jury is out on kale. We eat a lot of kale and broccoli.

  • Apparently the Popeye spinach myth happened because someone got the decimal point in the wrong place!

  • Thank you so much for this. I was in hospital in the fall for septicemia and they noticed my calcium was quite high so d/c'd my Rocaltrol (Calcitriol) that I had been on by prescription since my PMR diagnosis 2 years earlier (GCA since last fall).. I've just been taking plain Vit D drops. I use a food diary app and was very surprised to find I am always low in calcium intake even though I am a big milk and dairy lover. So this morning my daughter is going to pick me up some calcium and I didn't know what kind so thank you. I have kidney problems which is maybe why my calcium was high but I think I've been off it long enough. I also stopped my biphosphonate after reading up on it so have been worried about my bones. Edited:...I am having great difficulty with nausea, hence being unable to eat and losing you have a recommendation for my particular case? Thank you.


  • If you can exercise (weight bearing, like walking) that will help your bones as much as calcium intake. You also need the other micronutrients Admiral listed. If you take extra calcium there may also be a need to get extra magnesium so those two elements don't go out of balance. Vitamin K2 (not K1) is often lacking in our diet and should be supplemented. If you take Vitamin K2 the calcium should go into the bones where it belongs and not stay floating around in your bloodstream ready to settle into organs and onto the walls of blood vessels where we don't want it.

  • Thank you, unfortunately re the exercise I'm pretty well in bed right now.....but will follow your recommendations for Vit K2....I have a friend trained in alternative health and will check about the magnesium much to be aware of.....


  • I got curious so I googled exercises while bedridden and there is a bunch of stuff one can do, depending, of course, on one's condition. :)

  • I was given a sheet from physio of exercises to do in bed, but with this kind of weakness I can't even manage them....and I know all too well how much weaker you get the less you daughter, bless her, thinks I just have to try harder but all of us know it's not that easy....I remember telling my mother that as her cancer took over, mum you just have to try harder, and she just smiled at me....I now understand....thanks very much HeronNS😊


  • Maybe this will help. When I was immobilized with a broken leg I was advised to simply tighten and release my muscles, particularly in the broken limb which was not allowed to bear weight for over a month. I was told this would help maintain at least some level of fitness so once the bone was knitted I'd be literally a step ahead for being able to walk again, or do physio. It also helped to pass the time. Purely isometric, just clenching and unclenching muscles.

    This is pretty basic - one of the exercises is just to exercise the hand Another requires another person to provide resistance.

  • Thanks so much for this 😊 exercise I was given was to tighten the 'butt' muscles, and it's amazing how much strength it takes.....but I know I have spurred me on, thanks again

  • I assume you do know WHY you have a nausea problem?

  • No, I don't....?

  • Then maybe it should be investigated??? To be sure it isn't due to something else. One or two people have said nausea was part of the GCA before diagnosis - but being on pred improved it. Having PMR or GCA does not stop you having other problems.

  • Thank you PMRpro....I've been investigated thoroughly in the past and left 'only' with a diagnosis of colonic inertia, which can be a challenge, but the nausea seems to come at fairly regular intervals, not obviously related to anything, lasting weeks to months, unresponsive to even the strongest antiemetics....I doubt it's the GCA/PMR if I left that impression, but as I said I've never felt well since diagnosis.....I often wonder how many do well as they probably wouldn't feel the need to seek out a support group, I know I didn't with the rheumy said something last visit (wish I could remember what lol....duh, Pred brain.....anyway....) that spurred me on to do know how awful this disease is to live with?! which he quietly said....yes, I do know.....I felt some sort of validation at least....sorry for the ramble......


  • No, you didn't create that impression. What I meant was that, although there are people who have suffered nausea due to GCA, it is the exception and I'd be concerned there might be another cause.

    I wonder if he's had PMR or a family member has had it. Because my experience is that most rheumies DON'T have any idea how bad it can be - and a lot believe that once you are taking pred you are totally back to normal. I know that because they have told me so! And when you explain what it can do and how little pred does for some aspects they are VERY surprised.

    I think I can fairly say I feel pretty well - but I do realise I am lucky. I certainly didn't feel well with PMR for 5 years without pred! And I had 9 months on methyl prednisolone where I felt awful - nothing but adverse effects and it did nothing for the PMR even at 20mg. The Lodotra I am on now has been a minor miracle but it isn't available to most patients on the forums (I don't live in the UK).

  • Yes, I wondered the exact same thing, whether he had someone close to him with the disease or dealing with Prednisone even....when I read patient reviews on him there came across often the feeling that he could put himself in their shoes

    I sailed through PMR the first time with never a thought to the disease.....probably would have thought people were exaggerating if they complained....who knew?!

    I'm glad you've found something to help you feel well....I need to hear that there is the possibility.....carry on 😊

  • Hi doralouise, I too suffered from nausea and loss of appetite for the first 2 months after diagnosis. When this passed, I regained a couple of pounds, but the problem has recently returned. I describe PMR as a rollercoaster ride with more downs than ups.

  • Thanks for your input....last time this happened I lost 15 lbs which is always ok with the Pred weight increase, this time 11 so far....have no idea change in meds or tapering.....I doubt I've had more than a handful of days feeling ok let alone well in the last year or more since the GCA PMR was a walk in the park compared to's no life at all.....


  • Sorry to hear of your discomfort Doralouise. I have bounced back and forth between feeling lousy and feeling great. For me trembling (now gone) was the worst side effect.

    I am 6'1" and was 201 lbs when the PMR started......I am now at 180. Unfortunately I lost quite a bit of muscle in addition to my pot. I am quite active once again, but don't feel as though I am getting stronger.

    Compared to others, I have no complaints.

  • I have had the trembling at different times but not now....never knew if that was the disease or the Prednisone.....I'm glad to hear you have no complaints 😊....I look forward to being able to report that....


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