30 Oct Vitamin D: Are you getting enough?
Let me start by answering the title of this article with a resounding “PROBABLY NOT!”
Vitamin D is probably my favorite supplement. It is inexpensive, can be taken in many different ways (I’m partial to the liquids myself), and it has a library’s worth of clinical benefits (see links to peer reviewed articles documenting the relationship between vitamin D levels and:
Cardiovascular disease https://www.ncbi.nlm.nih.gov/pubmed/25634511
Fracture prevention https://www.ncbi.nlm.nih.gov/pubmed/15886381
Restless leg syndrome https://www.ncbi.nlm.nih.gov/pubmed/25148866
I could go on but you get the point.
It is important to note that most of the research on Vitamin D observes only an association, and not a causation between Vitamin D levels and various health outcomes, however, one clear trend emerges: Higher levels of vitamin D in the body are associated with better health outcomes across several domains, and lower levels are associated with worse outcomes.
Vitamin D is actually a hormone. Most vitamins work as co-factors in energy metabolism, meaning they bind to, and thereby activate, an enzyme that then breaks down substrates (food, mostly), and allows your body to harvest fuel from that substrate. In contrast, hormones are cellular messengers. They tell cells in other tissues and organs to behave a certain way, for example, to secrete more insulin, or to uptake more calcium. By virtue of being a hormone, Vitamin D does more in the body than a vitamin. This is part of why it gets so much attention.
Often called the sunshine vitamin, Vitamin D is more difficult to get than many other vitamins, say Vitamin C, readily available in citrus, or Vitamin B12, found in some meats and many leafy greens. Fatty fish and eggs supply some Vitamin D, and dairy foods are usually fortified with Vitamin D. It is estimated that 10 minutes of direct sunlight exposure also provides adequate Vitamin D, however concerns about sun exposure and skin cancer must also be taken into account.
Vitamin D is one of the fat soluble vitamins: A, D, E, K. Since these vitamins get stored in fat cells, there is a concern of toxicity when taking Vitamin D supplements, and while we should be cognizant of this fact, fears of toxicity should not outweigh the numerous benefits of having adequate levels of Vitamin D.
So, how do you know if you’re getting enough?
The best thing to do is to ask your Doctor. Vitamin D lab tests are not covered under OHIP, but cost about $30, depending on what lab you go to. Serum levels below 75 nmol/L are recognized as insufficient.
In having many conversations with clients about Vitamin D over the years, a commonly held belief is that if one drinks a reasonable quantity of milk, plus gets outside in the sun some, that vitamin D maintenance will take care of itself. In fact, I used to think the same. However, after years of seeing the test results of clients’ Vitamin D levels, I observed something amazing.
Out of more than 500 tests of Vitamin D levels, the only people who’s vitamin D levels were above the threshold of insufficiency were those taking a supplement.
To put that another way, if you live in Toronto or a city with a similar amount of sunshine, I and you don’t take a vitamin D supplement, it is almost certain that you will be in a state of vitamin D insufficiency.
Currently, Health Canada recommends 600 IU (international units) for children and adults ages 9-70, with 4000 IU being the upper recommended limit and 10000 IU the absolute upper safe limit (https://www.ncbi.nlm.nih.gov/pubmed/17209171) . Most supplements contain 1000 IU per dose, whether a dose is a drop, capsule, or tablet. Clients I have worked with seem to do well with doses between 1000 – 4000 IU daily, seasonally adjusted so that they are taking more in the winter months and less in the summer months. After a few months of supplementation, we expect levels to climb above 100 nmol / L and for the individual to experience increases in energy and sleep quality, as well as other more difficult to measure outcomes, like reduced risk of osteoporosis. Hypervitaminosis D is defined as having serum levels higher than 160 nmol/ L (https://www.ncbi.nlm.nih.gov/pubmed/26995293)
It seems that as long as you stay within Health Canada’s recommended guidelines that you can optimize your Vitamin D levels while mitigating the risk of risk of toxicity.
If you have never taken a Vitamin D supplement before, now is a great time to start, as we head towards the dark winter months. Vitamin D3, the active form, is the most researched and most readily available at any health food store. Look to spend about $30 on the supplement you choose. Liquids are the most economical, with many high end liquid products supplying close to a years supply at the $30 price point.