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Calcium and bone health – form matters

I was inspired to write a post about calcium and bone health after a comment from a client who happens to be a geologist.  When I mentioned that calcium carbonate is not the ideal form of calcium to supplement with, she replied, ‘that’s limestone’. 

Calcium carbonate is the most common form of calcium in supplements such as Adcal and the form of calcium added to plant milks.  So you’re basically supplementing with rocks, which is very different from the form of calcium naturally found in food!

Too little calcium or vitamin D contribute to osteopenia and osteoporosis, which are both conditions where there is too little mineral in the bone. Osteopenia is a more moderate form of the disease; osteoporosis is more severe.  Many nutrients play a role in bone health and calcium and vitamin D are certainly not the only ones, but in this post, I’m going to concentrate mostly on calcium. 

Calcium requirements vary slightly depending where in the world you are, but in the UK calcium requirements for men and women are 700 mg a day and increase to 1000 mg a day if have osteoporosis. 

What’s wrong with the way many people are advised to supplement with calcium?

  • The supplement, Adcal, is frequently prescribed which is a supplement that contains a high dose of calcium carbonate and not very much vitamin D – most people would benefit from more vitamin D and less calcium.  Calcium carbonate is a poorly absorbed form of calcium and has been shown to cause calcification of the arteries.  So, instead of the calcium going into the bones it’s deposited in the arteries.  Calcium carbonate can also be constipating for some.
  • Little to no consideration is given to the calcium content in the diet.  A calcium supplement should supplement what you’re not able to obtain via food.  Therefore, if you’re consuming three servings of dairy foods a day (for example, 1 cup of milk, 2 slices of hard cheese and 200g of yoghurt) there certainly isn’t a need to take a high dose of calcium. 
  • Vitamin D isn’t routinely tested or monitored and for many the amount of vitamin D in Adcal is not sufficient. Vitamin D is needed to deposit the calcium where it belongs, in bones and teeth. 

What do we advise:

  • Preferably supplement with a form of calcium known as calcium hydroxyapatite, which is the form of calcium in bones and bone meal.
  • Take supplemental calcium in two smaller doses, instead of one large dose a day. 
  • Assess the calcium content of your diet and then decide how much supplemental calcium you require.
  • If possible, try to get adequate calcium via food by including some of the following foods in your diet; milk and fermented dairy products (e.g. yogurt, kefir, cheese), leafy greens, broccoli, Brussel sprouts, almonds, chia seeds, canned fish with edible bones.
  • If you don’t consume dairy products ideally choose unfortified plant milks and supplement with calcium hydroxyapatite.
  • Test and retest your vitamin D to find the optimal amount of vitamin D that you need to supplement with at different times of the year.
  • Pay attention to your intake of other nutrients beneficial for bone health such as vitamin K1 and K2, and magnesium.
  • And lastly, don’t forget about the importance of resistance exercise for bone health.