Calcium Supplements – You’re barking up the Wrong Tree 

It’s not uncommon for people to be supplementing with large doses of calcium, based on seemingly low calcium levels in blood work.  

But what does low Calcium really mean?

Pathology testing can reveal quite a lot of information about a person’s biochemistry, but sometimes it requires initiation into the inner circle before the true esoteric meaning can be revealed.

Calcium is one of these nutrients where “all is not what it seems”.  We all know calcium is imperative for bone density, which is why we’re told to drink our milk (cough), to keep our bones healthy right through into old age.  Must have something in my throat, sorry about that.  If calcium were so important here, then you would think it would make sense to evaluate blood calcium levels to see where we stand?  If we’re low we can increase foods like tofu, sardines, tahini, greens, etc.[1][2]  If calcium levels are good then you have nothing to worry about, and should bounce nicely if you trip over a curb.

The thing about calcium is that we should never be low.  The balance of calcium works by a gentle symbiotic tug of war between parathyroid hormone (PTH), released by the parathyroid gland, and calcitonin, which is released by the parafollicular cells of the thyroid gland.  Each acts as the regulator of the other, and both are involved in maintaining skeletal and plasma calcium levels.[3]

When we have too little calcium in the blood stream, parathyroid hormone is released, which causes calcium from the bones to be mobilised and released into the blood stream.  And when calcium is high, like after big plate full of sardines (mmmm), calcitonin is released, which helps us absorb it and deposit the excess calcium into the bone matrix.

 

As you can see, blood calcium levels should be nicely balanced at all times.

So then why do we see levels fluctuate??

Lets have a closer look at these key hormones involved in the regulation of Calcium balance.

 

Calcitonin

As we’ve seen, calcitonin is secreted in the presence of calcium, but also in the presence of gastric acid (created by gastrin and pentagastrin).  Any medication that decreases gastric acid can alter the release calcitonin and interfere with calcium homoeostasis.  These include commonly perscribed; Histamine-2-antagonists, such as Zantac, Cimetidine & Tazac; and Proton Pump Inhibitors (PPIs) like Omeprazole, Nexium, and Rabeprazole.  In 2014, Nexium was the 9^th most commonly prescribed medication in Australia.[4] There is supporting evidence that prolonged use of these medications may impact bone density and increase risk of bone fracture.[5][6]  They will also cause many other nutritional deficiencies.

Parathyroid Hormone (PTH)

PTH is regulated by the presence of calcium, but also Magnesium.  Very low magnesium levels can cause a block in the function of PTH, which will cause a drop in serum calcium values.[7]  Clinically I see this as a huge driver for low calcium levels, and use it as a marker for magnesium status.

We all know the importance of magnesium.  Every supplement company sells 1 or more forms of magnesium, every Tom, Dick, and Harry has put themselves on it, we swallow it, drink it, bath in it, and even rub it on our skin.  It’s a wonder we don’t roll it up and smoke it!

 

If Magnesium is so important, why don’t we test for it?

The problem with measuring serum magnesium levels directly is that it’s very inaccurate. Only 1% of magnesium is found in the blood!![8][9] The rest is found inside the cells and in the interstitial fluid (fluid surrounding cells).  A person would have to be severely depleted for it to show any relevance in blood testing.

Calcium is maintained within a fairly narrow range of 2.2 to 2.7mmol/L, with the ultimate goal being 2.4mmol/L.[10] If you see levels less than this in your own results (and you’re all keeping copies of your results, right?), then increase the amount of magnesium you’re smoking, uh I mean consuming, because Magnesium is the likely culprit!

In  my professional opinion, it’s always best to work with a trained practitioner who can provide you with more insight than can be squeezed into a short article.  Very high and very low calcium can be an indicator of more sinister issues, and should not be ignored

Summary

• If you want to test for calcium, you’re best to measure Vitamin D, beta Cross Laps, parathyroid hormone, phosphate, ALP, osteocalcin, female reproductive hormones, testosterone, or request a DEXA scan.
• You can get plenty of calcium from foods like tofu, sardines, tahini, greens etc.
• PPI’s and H2-antagonoist will deplete calcium, and many other nutrients.
• Serum calcium levels should always be in range (2.4mmol/L is ideal).
• Parathyroid hormone draws calcium from skeletal bones when needed, and is regulated by magnesium.
• Calcitonin deposits calcium back into skeletal bone, and is triggered by gastric acid.
• Low Calcium is an indicator of low Magnesium
• Smoking magnesium probably isn’t a good idea

If you need a keener eye to go through your apparently “normal” blood results, appointments can be made by jumping on the dog and bone.  Skype sessions are also available.