This is actually a very pertinent question and one I have asked many times. Why are some many patient’s vitamin D levels very low despite good sun exposure. I may have the answer.
When researchers first discovered that levels of vitamin D deficiency were darn near ubiquitous in our population, the initial thoughts ranged from particulate matter in the air blocking UVB light penetration to heavy use of sunscreen.
None of the ideas seemed to fit completely. Sure, the average person lathers up with SPF 300 to walk to the car, but what about my patient who swam outside on a high school swimming team and still had a vitamin D level of 17 (optimal range 60-100) at the END of season here in Arizona?
Then I came across this particular study. While it is a rat study, the concepts put forth could answer the question for at least half of the population.
Yup. Makes sense given that upwards of 50% of the population are on this trajectory, and the numbers are likely much higher.
Here’s how it works:
- The diabetic spectrum, even in its early stages, is very damaging to the kidneys.
- Studies have shown that, in Type 2 diabetic rats, there is a significant loss of vitamin D and vitamin D binding protein (a protein in the blood that holds vitamin D while it floats through the bloodstream) in the urine due to kidney damage.
- This study confirms that the same problems exist in Type 1 diabetes as well.
Makes for some very interesting fodder, wouldn’t you say? And, if this holds true in humans (and I can’t see any reason to believe that it wouldn’t) certainly goes a very long way towards explaining why so much of the population has low vitamin D levels.
It also helps to explain why so many patients have a hard time boosting their vitamin D levels despite high levels of supplementation.
Here’s some further musings…
Some have suggested that low vitamin D levels are not the problem, but rather, the body lowers the level of vitamin D in response to a disease state such as cancer. Because of this, for someone with chronic disease, they should do everything possible to almost eradicate vitamin D in their blood. I firmly disagree with this hypothesis and treatment approach, even having one patient who went through the protocol and got VERY ill from it.
But what if low vitamin D is just yet another marker of physiology gone haywire as our bodies move towards diabetes?
It would not be the first time that we have looked at a single marker (like cholesterol) and thought that low levels, by themselves, were important, rather than looking at the big picture.
This also means that all the doctors out there diligently checking vitamin D and recommending supplementation but not addressing other aspects of lifestyle (like living an anti-diabetic lifestyle) are, once again, missing the boat entirely.
An additional interesting note to this study. The researchers also looked at whether the addition of resistant starch (think fiber—or you can read a previous blog article on the topic by clicking here) could affect the loss of vitamin D through the kidneys.
Wonderfully, the resistant starch virtually eliminated all the vitamin D lost through the kidneys. Given that the resistant starch in a higher fiber diet would go a long way towards avoiding or managing diabetes, it meshes nicely with the findings in this study. Higher fiber, more anti-diabetic diet = higher vitamin D levels. Not a bad outcome, regardless of how you look at it.
So, from now on, I know that, in those patients whose vitamin D levels just won’t budge despite strong supplementation, increasing the fiber in the diet and an overall anti-diabetic diet (my personal recommendations can be found in my free eBook by clicking here) will be strongly recommended.