Some confusion over Vit D and Calcium supps - Thyroid UK

Thyroid UK
101,241 members115,498 posts

Some confusion over Vit D and Calcium supps

So got my Vit D results back just now. It is apparently 'Adequate' which is better than I thought it might be! I've done some reading round on this site and elsewhere but am still not entirely clear. Should I supplement with extra D3 in the light of these results? I got my Calcium results yesterday which showed:

Calcium 2.35 mmol/L (2.200 - 2.600)

Corrected Calcium 2.32 mmol/L (2.200 - 2.600)

Albumin 41.7 g/L (34.00 - 50.00)

Currently I already take a Calcium/Magnesium/D3 supp (didn't take them for about 3 days prior to the test), have done so on and off for very many years. I do so primarily because I was never a milk drinker from early childhood, and am a vegetarian. My main calcium source now would be cheese and yoghurt. If I leave off my Ca supplement, after around 1 week I'll start getting excruciating lower leg cramps at night, so I don't want to discontinue it! Clearly I must need it?

My current supplements give me: Calcium: 1500 mg, Magnesium: 188 mg, Vit D3: 7.5 microg, Vit K: 38 microg.

I admit to being quite surprised that Calcium supplementation isn't recommended (but then I am rather out of the loop!), but looking at my results I don't appear to be over-medicated.

You can see my other test results in my previous post for B12, folate, ferritin (which all came in on the low side), and thyroid (shows Hashi antibodies).

My current symptoms are: very brittle nails, hair loss on legs/lower arms, fatigue (always crash after lunch and need a couple of hours sleep). This is consistent with hypothyroid and I feel I've had this coming on for several years at least, but like many have dismissed some of the symptoms as 'stress', 'depression' etc.

I'm trying to get off gluten completely at the moment, but it's a 'work in progress' !

10 Replies

7.5 mcg of vitamin D3 is equivalent to 300 iU.

Just as a comparison, to get my own vitamin D3 from about 60 nmol/L up to about 100 I needed 3000 IU of vitamin D3 per day. Some people with lower levels will need a lot more. Clutter for example, took 40,000 iU per day (prescribed) for a while.

Vitamin D supplementation increases the body's absorption of calcium, and this is why calcium is rarely recommended on this forum, if the dose of vitamin D is high enough.

Because of the extra absorption of calcium, it is essential to take vitamin K2 in addition to the vitamin D to direct that calcium into the bones and teeth. Magnesium supplementation is also essential (avoid magnesium oxide it is not worth the money).

If you were to take more vitamin D3, and it raised your absorption of calcium from your diet, I have no idea whether you would need to take your calcium supplement as well. You would need to test to keep tabs on what your calcium levels were doing, and then decide for yourself.


I should also have mentioned - I need 2000 iU of vitamin D daily just to maintain my level at roughly 100 nmol/L. And again, some people need far more.

1 like

Hmmm yes, I am thinking I'd definitely need to monitor my Calcium closely. I do actually take 2 Calcium supplements, the numbers above are the combined total, so I could at a pinch ditch one and so lower it and see how that goes. I've ordered quite a bunch of vitamins, sub-lingual B12, Jarrow's B complex, K2, Iron Bisglycinate. Already have Vit C at home. Thanks for those articles, will give them a good read. :)


I don't understand what's going on with me, but while supplementing vitamin D3 my low serum calcium dropped further, and rose when I stopped supplementing.


I'm afraid I have no idea why that might have happened, sorry. :(


Does this article give you any clues? Sadly, the author doesn't mention magnesium which I think is a big oversight.


Thanks, the mentions of cortisol and vitamin D receptors are of interest.

I've had endocrine hypertension tests for pheochromocytoma, Conn's syndrome, and now Cushing's syndrome (still awaiting the results, after several weeks), and low calcium can feature, so it was unfair of me to link supplementing D3 with lower calcium.

According to Inflammation Therapy, infections can mess up the vitamin D receptors, but their treatment protocol isn't readily available in the UK.


My personal opinion is, you don't need the calcium, but you do need the D3, K2 and magnesium. The cramps are probably from low magnesium. Excess magnesium is excreted, excess calcium isn't.

If you are eating cheese and yoghurt, you are probably getting plenty of calcium, plus a lot of fruit and veggies contain calcium.

Calcium supplements, on the other hand, are not a good idea.


As an aside, when I chipped a bit of my elbow bone in a fall a few years ago my Doc wanted to give me a bone scan, which I would have been happy to have except with my crook back I couldn't travel to the next town to have it, so I ended up not. She said 'we might need to give you Calcium supplements' which I recall made me snort at the time as I already took them and quite honestly didn't believe a chipped elbow indicated I might have osteoporosis!


After doing a bit of reading round re Magnesium I've decided for now to take the conservative route. I'll not take any D3 supplement for the moment, I'll put my current Ca/Mg supplement on hold and get some Magnesium Chelate or Citrate instead. I'll be taking K2 as planned. Then in a few months I can test my blood Calcium again and see if there's any difference, also obviously keep an eye on any leg cramps. As I also get back spasms from time to time perhaps the added Magnesium will knock those on the head. After all I can always add the Ca supps back again if this plan doesn't work.


You may also like...