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Why You Should Think Twice about Taking Calcium Supplements

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These dairy products, bone-in fish, and leafy greens can eliminate the need for calcium supplements.
Eating foods rich in calcium, like dairy products, leafy greens, and bone-in fish, can help you avoid the risks of calcium supplements. iStock/piotr_malczyk

I’ve come to believe, through my experience treating hundreds of patients, that many of us benefit from supplementation even if we’re eating a nutrient-dense, whole-foods diet. Some nutrients are challenging to get through food alone due to challenges like declining soil quality, a growing toxic burden, an increase in digestive issues and chronic diseases that interfere with nutrient absorption, and several other factors that are now common in the modern world. The latest statistics suggest that most Americans don’t get enough of several essential vitamins and minerals, and low nutrient intake is associated with a higher risk of chronic disease and a shorter lifespan.

That said, there are some nutrients that we need to be careful with when supplementing. More is not always better, and the specific form of the nutrient in the supplement can make a big difference in how it impacts us. This doesn’t mean that we should never take these nutrients as supplements, but it does mean that we have to be smart about how we supplement with them.

Calcium supplements are a prime example of this.

Do Calcium Supplements Work?

Calcium has become extremely popular as a supplement, especially among aging women, in the hope that it will prevent fractures and protect against osteoporosis.

We’ve all seen the products on the market aimed at the “worried well,” such as Viactiv and Caltrate, suggesting that supplementing with calcium can help maintain bone health and prevent osteoporosis. Osteoporosis is a serious concern in women’s health, and it affects at least 10 percent of American women. (1) Yet the evidence that calcium supplementation strengthens the bones and teeth was never strong to begin with, and it has grown weaker with new research published in the past few years.

Are you taking a common supplement that may increase the risk of heart disease, stroke, and death? Read this article to find out. #bonehealth #heartdisease #nutritionalsupplements

A 2012 analysis found that consuming a high amount of calcium beyond recommended dietary guidelines, typically from supplementation, provided no benefit for hip or lumbar vertebral bone mineral density in older adults. (2) A 2007 study published in The American Journal of Clinical Nutrition found that calcium supplements don’t reduce fracture rates in postmenopausal women and may even increase the rate of hip fractures. (3)

Are Calcium Supplements Safe?

Beyond being ineffective for bone health, standard calcium supplements are associated with some pretty serious health risks.

Heart Disease Risk

Studies on the relationship between calcium and cardiovascular disease (CVD) suggest that dietary intake of calcium protects against heart disease, but supplemental calcium may increase the risk. A 2012 study of 24,000 men and women aged 35 to 64 years published in the British Medical Journal (BMJ) found that those who used calcium supplements had a 139 percent greater risk of heart attack during the 11-year study period, while intake of food calcium did not increase the risk. (4) A meta-analysis of studies involving more than 12,000 people also published in the BMJ found that calcium supplementation increases the risk of:

  • Heart attack by 31 percent
  • Stroke by 20 percent
  • Death from all causes by 9 percent (5)

An analysis involving 12,000 men published in JAMA Internal Medicine found that intakes of over 1,000 mg of supplemental calcium per day—from multivitamins or individual supplements—were associated with a 20 percent increase in the risk of death from CVD. (6) Researchers suspect that the increase of calcium in the blood that occurs after supplementation may facilitate the calcification of arteries, whereas calcium obtained from food is absorbed at slower rates and in smaller quantities than from supplements. (7) It is also suspected that extra calcium intake above one’s requirements is not absorbed by the bones, but is excreted in the urine, increasing the risk of calcium kidney stones. The excess calcium could also be circulated in the blood, where it might attach to atherosclerotic plaques in arteries or heart valves. (8)

Cancer, Kidney Stones, and Other Health Risks

The Office of Dietary Supplements at the National Institutes of Health has compiled a comprehensive review of the health risks associated with excess calcium, particularly from supplementation. (9)

For example, daily supplementation of calcium at 1,000 mg is associated with increased prostate cancer risk and an increase in kidney stones. (10)

Additionally, a recent Swedish study reported a 40 percent higher risk of death among women with high calcium intakes (1,400 mg and above), and a 157 percent higher risk of death if those women were taking a 500-mg calcium supplement daily. Those rates were compared to women with moderate daily calcium intakes between 600 and 1,000 mg. (11) A Consumer Lab analysis found that many of the calcium supplements they analyzed failed quality testing for reasons including lead contamination and mislabeled contents. (12)

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Other Forms of Calcium Supplementation

Even if you’re not popping a calcium pill every morning, that doesn’t mean you’re not consuming supplemental calcium. Many commonly consumed foods in the United States are fortified with supplemental forms of calcium, including:

  • Orange juice
  • Breakfast cereals
  • Non-dairy milk
  • Bread
  • Instant oatmeal
  • Graham crackers
  • Other staples of the Standard American Diet

While these foods are typically eliminated on a whole-foods or Paleo diet, it’s important to pay attention to whether some of your fridge staples, such as commercial almond, coconut, or other varieties of non-dairy milk, are fortified with calcium. You may be consuming more supplemental calcium than you realize.

In addition, many multivitamins contain high doses of cheap or inferior forms of calcium that are not well absorbed. This can lead to an accumulation of calcium in the soft tissues (where we don’t want it), which in turn contributes to the adverse effects discussed in this article.

Not all multivitamins are created equal. When I formulated Adapt Naturals Bio-Avail Multi, I included a minimal dose (50 mg) of calcium, which is only 4 percent of the total daily requirement. I also used di-calcium malate, a highly bioavailable form of calcium that is much better absorbed than calcium carbonate and other forms of calcium.
Bio-Avail Multi also contains meaningful doses of vitamins A, D, and K2, as well as magnesium. Each of these nutrients plays critical roles in calcium metabolism and bone health and may be even more important for improving bone health than increasing calcium intake—at least for some people.
Vitamin E is another important nutrient for bone health—but here, I’m referring to delta- and gamma-tocotrienols, a newly discovered form of vitamin E, rather than alpha-tocopherol, the more common form that is in most supplements. Tocotrienols have several positive effects on bone health: they decrease bone resorption, increase bone turnover rate, and improve osteoblast number, bone formation, mineral deposition, and bone microarchitecture. Adapt Naturals Bio-Avail E+ contains 300 mg of delta- and gamma-tocotrienols (with no tocopherols), sourced from the annatto plant. Taken together with Bio-Avail Multi, you can have confidence that you’re getting the nutrients you need for optimal bone health.  

The Safest Ways to Get Enough Calcium

If you’re concerned about keeping your bones healthy, you’re better off getting your calcium from food sources like:

  • Dairy products
  • Canned, bone-in fish (e.g., sardines, salmon, etc.)
  • Dark, leafy greens
  • Seeds (especially poppy and sesame)
  • Almonds

The Recommended Dietary Allowance (RDA) for calcium for adult men and women is 1,000 mg—or approximately three servings of dairy products or bone-in fish per day. Pregnant and lactating women, and adults 70 and older, need 1,200 mg per day.

It’s critical to understand that healthy bone formation also depends on other nutrients like vitamins A, D, and K2, and minerals like magnesium and silica, each of which plays a role in regulating calcium metabolism. Some research suggests that consuming optimal levels of these nutrients may reduce the amount of calcium you need each day, due to their synergistic effects. Regular weight-bearing exercise can also make a big difference for maintaining healthy bones. (13)

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406 Comments

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  1. I have seen good results using MRM’s Bone Maximizer III with calcium from MCHC , K2 (MK7), vitamin D, and other minerals.

  2. Thank you for this info. I will check my multi vitamin . My mother has always taken calcium and at 70 + years she had open heart to replace two heart valves, one being calcified (having calcium deposits on it??) I’ll be in touch.

  3. Dr. Kresser,
    Your knowledge and willingness to share is a blessing. I know you cannot respond to every comment, but my children are dairy/gluten intolerant and I just found out thru homeopathic testing she is allergic to other biggies in our diet as well–salmon and almond (our calcium sources.) Can you please help with any suggestions. I am stressed and frustrated at the thought of giving them adequate nutrition. Thank you so much.

  4. Dr. Kresser,
    I’ve been caring for my wife for 7 years now. She is on full time oxygen now. She has COPD, chronic emphysema. For 10 years she was taking “calcichew” which is 1000 iu of vitamin D3 + calcium per tablet. She has been taking 2 tablets a day. I had her vitamin D levels checked and they were deemed “insufficient” at 20 ng/ml. I believe that because she is house bound and takes regular courses of steroids this is why she had such low levels. I upped her intake of vitamin D and raised her levels to 65 ng/ml. She is very underweight at 85 pounds. That’s an increase of 4 pounds from 3 months ago. She drinks around 3 pints of milk a day through milky coffees or chocolate. My logic is that I’ve raised her vitamin D levels and she gets her calcium from her milk consumption, which is more effective than the calcichew tablets. She has no appetite and other than the milk, she eats very little. However she is getting very forgetful and her short term memory is suffering. I just wondered whether the excessive milk consumption could be a factor?

    • How is her sugar intake? I first heard the term from Dr. Mercola and Rosedale: Type 3 Diabetes. That’s what Alzheimers and other such dementia may largely be. As time has gone by, more and more a link between chronic high blood sugar and memory loss is being recognized. And I do believe it’s a causal link. So perhaps go a bit easy on the sugar? Also, coconut oil supplementation, perhaps 2 tablespoonfuls a day, have been purported by the Weston A. Price Foundation to be miraculously helpful for memory loss, even in late stages. Here is the article, I think that you will find the personal story in there to be of great interest:
      http://www.westonaprice.org/know-your-fats/land-of-oz-attack-on-coconut-oil

      Good luck to your wife, and God bless you for caring for her so passionately for all these years.

      • Craig, thank you for your suggestions and kind thoughts.
        I think the short term memory loss is due to her poor oxygen levels more than anything else. Yes she does have too much sugar and eats so little that I can’t get her to eat healthily. Sadly that seems to be the case with this disease. She’s deteriorated to the point that eating is just too much effort. At least her milk consumption keeps her having some nutrition, and she has gained some weight.
        Ironically I eat a grain free, minimal sugar anti inflammatory diet that I have developed to suit me since she became ill.
        I follow the WAPF website and take in what they say.
        I’ve tried to get her to eat coconut oil, as I do, but she won’t.

        I think that I’ll just have to accept that milk is better than no milk in her case. If there is a detrimental effect to her brain, then so be it. I just hoped Chris Kresser had a view on this.

        In the past when she has been on courses of steroids, she has had tweaks of pain in her spine. Bone loss is a known side effect. This hasn’t happened since she’s been on so much milk, probably 8 weeks of steroids in the past 26 weeks, so it may help in that way.

        I posted this here because of the article being a bout calcium supplements, and her previous long term use of calcichew tablets.

        • If she’s willing to drink milk, would she be willing to drink milk or yogurt based smoothies? You could maybe get more nutrients for her that way. Although probably not coconut oil, unless you’re careful. It tends to make really nasty clumps in cold liquids.

          Just a thought I had reading your post.

  5. I eat a 99% compliant autoimmune variant of the paleo diet. Ran a few days worth of my dietary intake through nutritiondata.self.com. I was getting only 25% of the RDI of calcium. I also had symptoms of calcium insufficiency such as annoying cramps in my feet at night. After years of fearing calcium supplements because of bad press in the paleo community I decided to give 500 mg a day a go. The problem resolved within days.

  6. Hi Chris,
    What about Calcium D Glucarate to help combat high beta glucuronidase activity? Would it be better to just supplement with probiotics? What could be the cause of high beta glucuronidase activity found in the stool?

  7. Gastric Bypass Relevancy?

    Because I had a gastric bypass three years ago, this info on calcium has me concerned.

    I’m supposed to take calcium citrate supplements because my rearranged plumbing makes it difficult to absorb dietary calcium (especially the non-citrate variety).

    Does anyone have updated calcium intake information pertaining to people in my situation?

    Thanks,

    –Kirk in MN

  8. I’m suprised that you would endorse dairy as an adequate dairy source. Especially from a paleo perspective. Cows milk is a wonderful source of calcium–for calves. Unfortunately, the calcium it contains doesn’t seem to be bioavailable to humans for a number of reasons. For more info on this check out http://saveourbones.com/osteoporosis-milk-myth/. I would also mention to your readers the herb horsetail which is full of silica and helpful for bone health.

    • There’s a lot of pseudoscience in that article. Full-fat dairy consumption is linked with several beneficial health outcomes, including a lower risk of cardiovascular disease, obesity, diabetes and metabolic syndrome. (http://link.springer.com/article/10.1007%2Fs00394-012-0418-1)

      Rapid genetic selection over the past 10,000 years have increased lactase persistence, the genetic mutation that allows us to digest lactose, to the point where 1/3 of the global population has it. In some Northern European countries, the percentage of people with lactase persistence is approaching 100%.

      Even for those that are lactose intolerant, simply choosing full-fat dairy that is low in lactose (like butter, milk and hard cheese) or fermenting milk to make yogurt or kefir eliminates the lactose problem. Casein intolerance/allergy is rare.

      This paper (http://www.jacn.org/content/19/suppl_2/119S.long), among many others, shows that calcium in milk is well-absorbed. In fact, calcium from milk is much better absorbed than calcium from green vegetables, because they contain oxalate, phytate, or both—which inhibit calcium absorption.

      • This is something also confirmed by RBTI practitioners as well as by Ron Schmid in his book The Untold Story of Milk. The dominant calcium compound of milk is calcium gluconate. It is the most easily digested calcium compound for those who have a weak digestion.

      • Hello Chris. You say that “casein intolerance/allergy is rare.” What has led you to think this? I know many people who have intense reactions to dairy, even if it’s raw, fermented dairy from healthy, grass-fed cows.

  9. Hi Chris. I just had extensive preventive blood work and hair testing done. I have a lot of heavy metal issues and the chiropractor suggested using a powdered Vitamin C with Ribose of 4,000mg twice a day while going through chelation to get rid of the metals in my body. What do think of the detoxing effects of Vitamin C and the recommended dosages? I have had fibromyalgia for 20 years and am hopeful that if I eat the right foods, detox my body, and take the right supplements I can reverse the condition. Any suggestions in that area?

  10. Once you’ve been diagnosed with osteoporosis, then what? I’m only in my early 50’s. After being diagnosed I declined all the scary treatments, weaned off acid-blocking meds that I suspect contributed to it (although the prescribing doctor denied it), and changed my diet to mostly Paleo. Will bio-identical estrogen (plus progesterone) help?

  11. My naturopath has recently suggested that I take a cal-mag powder at night. I’ve read a lot of information stating that both calcium and magnesium cannot be at the same level in the body, one must be higher than the other. So what is the point of taking the powder if the milligrams is the same for both? And is it doing more harm than good? I am new to eating Paleo, and so far have been really strict, so would it be more beneficial to me to start including a small amount of dairy back into my diet to ensure I get the nutrients I need from food instead of supplements? I haven’t been brave enough to try organ meats yet!

  12. What If You Have Had Two Kidney Transplants, And A Parathyroidectomy!!! My Little Sister Has The Same Disease As I Do… She To Has Had Two Kidney Transplants, But Has Here Parathyroid Glands… She Had 87% Bone Loss In Her Hip N 85% In The Lower Lumbar!!! I Take Over 2400mgs. Calcium Carbonate Trough Out The Day, And 1600mgs. Magnesium Split Up With The Calcium… I Take An Anti Rejection Drug, That Leaches The Mag. Out Of Your System (prograf)… I’m A Raw Paleo Person!!! I Noticed A Huge Increase In My Calcium Levels (complete blood tests once every month), As Soon As I Started Eating A Quart Of My Own Raw Milk Yogurt, And 3/4 Of A Quart Of Raw Milk Everyday… By The Way, The Dexa Scans Show NO Bone Lose For Me!!! Of Course I Am A Bodybuilder As Well… I Put So Much Stress On My Bone Structure, It Is Unbelievable… I Suppose It Is All This Torque On The Bones That Help Keep Em’ Strong!!! I Did Back Off The Calcium Carb. 600mgs… Maybe I Should Do More!!! I Walk A Fine Line My Friend… I Enjoy Your Facebook Comments…

    Thank You, Tom P.S. When I Had My Last Transplant, They Told Me I Had To Take Fosamax, Because Every Person That Had Been Transplanted For The Last Ten Years Got Osteoporosis… I Said, “Well, I Hate To Burst Your Bubble, But I Don’t Have It, And I Have No Parathyroids”… They Were Shocked… I Said, “You Can Hang On To You Fosamax” 😉

  13. Chris,
    What are your thoughts on calcium (dietary or any type of calcium supplementation) during pregnancy? I heard from a midwife that a woman can increase her bone density during pregnancy only (after the age of 18)? Any weight to that?

    • I’m also curious about calcium in pregnancy. I don’t do well with dairy. I eat leafy greens about 4 times per week, and sardines and canned salmon weekly. A midwife told me that the fetus will take calcium from the mother’s bones if there is not enough intake. How many mg should pregnant women get daily?

      • Women require 5-7 times more mineral than men do in their childbearing years and 80% of that amount is calcium (Biological Ionization As Applied to Human Nutrition, p.80).

  14. Dear Chris!
    My experience is, that only exercises can prevent osteoporosis, and not calcium intake. I am a 57 years old woman, and 10 years ago I had to face the problem, that I am loosing bone density, and I have osteopenia. Calcium intake didn’t help at all, just my joints become aching.
    Then I read, that as strong your muscles are, as strong are your bones too, and I did exercises or ran every day at least one hour. The consequence was that I gained 5% bones density within a year according the bones density test. So I never have taken calcium supplement since then.

    • I began reading this article because I have periodically had brief, severe hip pain which I suspected was due to supplemental calcium. Yours is the first I’ve read about “aching joints.”

      After taking only two rounds of supplemental calcium/vitamin d/magnesium, my right hip hurt so badly that I was completely able to sleep. Staying off the supplement for 24 hours has provided significant relief!

      I’m convinced that the supplement severely aggravated an already weak hip joint, causing it to become much worse.

      I am also concerned that Vitamin C might also have aggravated the situation and have ceased taking C supplements.

      Can’t tell you how much better I am able to sleep, and feel such relief in my hip!

  15. At the age of 40 I was diagnosed post menopausal and severe osteoporosis. I refused traditional biphosinates and took Bone Power a calcium boron supplement. In 2 years significant improvement to osteopenia and 4 years later borderline normal bone density. I felt this calcium reversed my osteoporosis. Once normal bone test I plan to reduce my dose but faithfully have taken 1250- 1500 daily…..

  16. This is so timely! I just had a Dr appt this morning and my blood Ca level was L…well…1.11 and the low-range cut-off is 1.12!! She didn’t even ask me about my diet and proceeded to write me a Rx for Ca-Mg. I just kept my mouth shut, thinking to myself “As if I’m taking this”.

    I don’t eat dairy and I don’t regularly consume bone broth, and umm..never sardines…but I eat lots of veggies and I just presumed I didn’t have to worry much about it. I’m 28, active…..just wondering if this “low calcium” is even something I need to worry about? Is blood Ca to be looked at differently than bone mineral density?

    My mom was diagnosed with osteoporosis, but she’s trying to heal that with diet & supplements (and not the Rx the same Dr gave her!)

    • Check my comment above to Helen. It took about a year for me to build up to wearing all twenty pounds of my first weighted vest. I lost the twenty pounds I had gained since my early forties in the first year. Now I’m 61 and feel fantastic since I started to build my bones using the weighted vest. I can stand for hours whereas previously, even in my 30’s my legs and entire body would ache constantly. I think the bone building revved up my metabolism thereby improving my overall health/strength. Lately, within the past two months I’ve started eating pale type diet and feel even better. My skin is improving as well. I haven’t taken any calcium for the last 4 years or so. Sometimes I drink milk. Since starting pale 2 months ago I try to eat broth every few days or so. I would caution against eating a lot of fish if you are pregnant not matter what the science says. My child was definitely affected by my overeating canned tuna. Maybe eat it once a week, but science is always changing their conclusions and you may regret eating the fish. I know I do!!! Other than that I think Chris’ advice is great!

  17. I take magnesium glycinate but if I take a decent dose (anything above 300-400mg daily) for a while I start getting nocturnal calf muscle cramps and twitching. The only thing that stops this is Lifestream Natural Calcium powder. I don’t like taking calcium because of all the anti-calcium stuff I’ve read but when I put my paleo-ish diet into FitDay I see that I don’t get enough calcium. I’m hoping that the form I’m taking is food-like enough to be ok. It’s produced from a certified organic sea vegetable called Lithothamnium calcareum and “demonstrates advanced bioavailability. Lifestream Natural Calcium contains 32-34% elemental calcium and other important co-factor minerals including boron, magnesium, zinc, copper, iodine and sulphur.”

    • Had the same experience. Greater than 300mg/day of magnesium glycinate caused late night calf cramps. Taking about 200mg/day calcium bisglysinate resolved. Looking at the study Chris Kresser quoted wrt salmon bones showed rough 1/4 of the content absorbed from cod bones, salmon bones, and calcium oxide. Considering spinach’s oxalates only lets 5-6% of it’s calcium be absorbed, it could be that the magnesium glycinate’s good absorption unbalanced the extra/intra cellular Ca/Mg ratio. Some of the crucifers (e.g. broccoli) have about 50% of their calcium absorbed.

      • Exact same thing happens with me. “Too much” magnesium, and I get strong cramps and/or muscle twitching in my lower legs and feet, which are only resolved with calcium supplementation.

        And this review showed that even that the supposedly”evil” calcium carbonate was absorbed just fine even in patients with low stomach acid.

        http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2621390/

    • Ray Peat notes that calcium deposits are due to a calcium deficiency, NOT excess. Makes sense too, when one considers if vitamin D and calcium intake are too low, then calcium will be pulled from the bones…causing bone spurs, calcifications, etc..

    • There is so much pro-magnesium, anti-calcium propaganda to be had these days. We are told – and I believed – that all we have to do is take Mg by food or supps and it would somehow send the Ca to where it is needed, assuming we are also taking Vitamin D3.

      Some of us do need Calcium, it is that simple. I was taking only 200-400 mg of Magnesium every day, staggering it, and I kept getting mild cramps in my legs in the morning. I finally figured out it is Ca that I need. I take 2 – 200mg Ca Citrate pills a day and it is working. I also make sure I take Vitamin K2 & D of course.

      • Propaganda? Wow, it’s sad that facts have now been relegated to such nonsense. The fact remains, we do need calcium, magnesium, Vit. K2, D3, boron, etc. for bone and body health but we need it in forms that can be properly assimilated which may be what you’re health concern may be all about. Some forms of calcium, magnesium, etc. are poor and at times even neurotoxic in the body. Magnesium operates as a natural ‘relaxant’ and calcium as a natural ‘contraction’ in the body and if in the improper form or quantity will not work properly and cause issues; cramping being one. If one is not getting enough magnesium, then the calcium builds up in the joints, blood vessels, etc., so before you lay your complaint on ‘lack’ of calcium, you ought to look at the forms you’re taking and make sure you’re getting the proper ratio. We were taking 2:1 calcium to magnesium but found it woefully problematic and now are much healthier with a 1:1 or 1:2 ratio of Ca-Mg.

  18. Hi Chris,

    Thanks so much for your work.

    My kids (ages 5 and 8) are dairy-intolerant and get no dairy. Getting dietary sources of calcium into kids is hard, although I try! I give them chewable supplements of 500 mg twice per day (total 1000 mg) since they are in the process of growing bones. Should I stop giving it to them? Cut back?

    We eat mostly paleo plus rice. They are okay eaters, not great.

  19. I’ve been asking myself this very question. I KNOW that while on a strict Paleo diet my calcium intake is low and I do eat/drink bone broth, but not every day. So, how should a strict Paleo person get enough calcium without dairy if they don’t eat 2 servings of fish and bone broth every day?!

    What we women do if we are also pregnant and breastfeeding while on Paleo (no dairy)?

      • Eating a lot of canned fish though will mean higher intakes of potentially oxidized PUFA. Will it not?

        • Yes, it’ll be oxidized, but I’m just wondering how much compared to just cooking salmon fillets? I wonder if routine consumption of canned salmon could eventually cause issues, but I’m just guessing balancing it out with anti-oxidants from other foods would be fine.

      • I think you’re missing the point; Lauren asked about pregnancy and Paleo. Most women are told to limit seafood consumption to two meals a week during pregnancy. What would you advise in this case?

  20. What about whole-food based calcium supplements, which contain algae etc rather than calcium carbonate/ citrate?