The current recommendations to give large doses of vitamin D supplements to every man, his dog and his canary are misguided and potentially damaging. In the first part of this series i’m going to explore why this is the case, paying particular attention to the relationships between vitamin D, calcium and magnesium.
The recommendations are based on the observation that many people have low plasma vitamin D. Ostensibly, this couldn’t be more logical. The thinking goes like this: ‘Low plasma vitamin D is associated with a higher risk of disease. Increasing plasma vitamin D to the same levels as those found in healthy people should alleviate that risk. Vitamin D deficiency is caused by inadequate exposure to sunlight, so supplementation is the best way to correct this.’
Unfortunately, there are several dangerous suppositions inherent to this argument.
Firstly, it is an assumption that that low Vitamin D levels are a causative, rather than correlative, factor in disease. Moreover, the belief that disease risk can be reduced by raising the low levels in unhealthy people (with supplements) to match those of healthy ones, fails to consider the possibility that the levels were low for a reason. If they are low for a reason (they are!) then forcibly manipulating a symptom without treating the cause could make matters worse.
Secondly, there are seven micronutrients needed to synthesise vitamin D, as well a sunlight. These are B2, B6, C, E, magnesium, zinc & boron. A deficiency in any of these could contribute to low levels. Supplementing vitamin D without ensuring these nutrients are replete could cause other problems (it does!).
By why would the body deliberately suppress the level of such an important nutrient/hormone? Could it be trying to protect itself?
To answer these questions adequately, we need we need to understand the role vitamin D in the body. Primarily, it is responsible for increasing the amount calcium in the blood. It does this in three ways: It increases the absorption of calcium from food in the intestinal tract. It causes the kidneys to retain calcium. It stimulates the production of osteoclasts which dissolve bone, thereby freeing calcium into circulation. 
It is extremely common to see elevated calcium of a Hair Tissue Mineral Analysis (HTMA). In fact, probably 90% of all cases will present with this pattern. When calcium is high on a hair test, it tells us that the body’s calcium metabolism is disrupted. This usually means that there is some form of calcification happening in the body, especially when combined with a low magnesium level. This is not good. Calcification is associated with virtually every major disease. Fortunately the situation is fairly easy to correct.
Since vitamin D increases plasma calcium, could the body have intended to keep the level low to protect itself from exacerbating any preexisting calcification? I think so.
Another factor contributing to the tendency to calcify is magnesium deficiency. Magnesium is needed to keep calcium in solution; without it calcium precipitates. It also acts as a calcium channel blocker, protecting cells from excess calcium.  The two minerals need to be in balance; magnesium is the yin to calcium’s yang.
The more pronounced a deficiency is, relative to calcium, the more extreme the calcification will be. If the body is deficient in magnesium, it might keep vitamin D low to avoid increasing the calcium to magnesium ratio further. If this is true we should expect magnesium levels to be closely correlated with vitamin D. This is exactly what has been observed. 
It is interesting to note that the active ingredient in Quintox – a rat poison – is Cholecalciferol. Presumably Quintox works by causing an extreme disturbance in calcium metabolism, ultimately resulting in death. Cholecalciferol is Vitamin D3. Vitamin D3 is what is used in vitamin D supplements. Before you panic, remember that you aren’t a rat and that the relative dose is incomparable to any dose likely to be taken via supplementation (although some protocols challenge this assertion). The example does, however, reveal something important about the underlying mechanism of action.
An equally important piece of the puzzle is the fact that magnesium is required for the synthesis of vitamin D. If we’re deficient in magnesium we won’t be able to produce as much: There is a natural, rate-limiting, protective mechanism built into the process. Even without much magnesium we should still be okay, as we won’t produce enough vitamin D to sufficiently increase the plasma calcium to cause damage… Unless we take a supplement!
By understanding the relationship between these nutrients, we can begin to grasp how supplementing vitamin D can be counterproductive: It overrides our bodies regulatory systems; by forcibly elevating the vitamin D level we skew the calcium to magnesium ratio, making ourselves vulnerable to the risks of calcification. In the presence of a magnesium deficiency the situation becomes more extreme. By taking vitamin D in response to a low plasma level without first addressing why it was low, we exacerbate the conditions our body has, so ingeniously, sought to protect us from.
In the next part of the article we’ll look further into the problems with vitamin D supplements, considering its relationships with other nutrients and hormones. We’ll also look at the effects of vitamin D supplementation on an HTMA.
If you have any questions i’d love to hear from you.