How much Vitamin D do you need?
That depends, as usual, on a whole lot of things. I’m taking 5000IU/ day myself; I’ll tell you later how I came up with this number, which included a consult with a physician.
I've read a crap load (that's a lot) of data on vitamin D lately. A couple hundred pages. So here is not everything, but nearly everything you need to know about vitamin D today..
A caller on the Richard Cloutier Reports show CJOB radio (CJOB.com) March 23, 2010, where I was a guest talking about a Stats Can report on the health of Canadians, asked the question, “what about the Inuit? They have been living in total darkness half the year for generations. How do they get vitamin D?” It’s a great question.
The traditional Inuit diet had lot’s of seal and whale blubber, seal liver, bird eggs, fish eggs, arctic char, and other marine life that is high in vitamin D. However since the Inuit diet has become more westernized we now see vitamin D deficiencies in the Inuit.
This leads me to letting you know that we can, in the most technical sense, get enough vitamin D from foods we eat, if we eat whale blubber, seal liver.. (and all the above) in sufficient quantities. What.. no whale blubber at the corner store?
OK so probably not so realistic to get enough enough vitamin D in the winter from the foods that are readily available and normally consumed by most Canadians. I don’t like the idea of swallowing a pill in the place of food. After all I’m the guy who has said for decades that unless you have a specific medical condition, there are pretty much no circumstances where you can’t get all the vitamins and minerals you need from a healthy diet.
In fact studies show us that we absorb and utilize nutrients from whole unprocessed foods far better than popping pills.
I do advocate taking vitamin D pills in the winter for northern latitude, or equally distant from the equator southern dwellers.
Did I sell out? I’m not driving my dream Tesla Roadster yet, so no, I have nothing to gain personally from encouraging Canadians to take vitamin D supplements in the winter. Well I do have something to gain.. gratification. Call me a sap if you will, but it makes me feel to good to know I have influenced someone to do something to improve their health.
This isn’t a food versus pills dilemma. We get the vast majority of our vitamin D from sun exposure, not food. That is how our biological need for vitamin D is met. Winter = inadequately intense sunshine to stimulate vitamin D production. This is a pills versus sunshine dilemma. We could all move close to the equator during the Canadian winter, but who want's to do that? I've got a tongue-in-cheek picture around here somewhere..
I don’t get caught up thinking I could be getting my 5000IU of D from food because currently that is unrealistic. I know it isn’t lack of poor nutrition, it is lack of sunshine that prompts the need for D supplementation; this is a critical difference between the reasoning for popping D pills versus say, C pills. I can easily get enough vitamin C from diet. That’s easier than falling off a log.. which I have done. And it was pretty easy. It didn’t benefit my health though..
If you ask a registered dietician for an “official” recommendation for vitamin D they are bound by professional standards to tell you only what Dietitians of Canada and Health Canada say. That’s not necessarily a bad thing.. we need strong standards that are proven through a rigorous scientific process.
But what to do when the scientific community is the midst of change and the new recommendations are not yet confirmed “officially”, but the published research and the medical consensus is clearly different than the current recommendation?
Anytime you have a government behemoth trying to act on something current, “current” doesn’t seem to be part of what they do. To Health Canada’s and Stats Can’s credit recommending dietary intakes of vital nutrients is not something you want to rush, but when in the midst of change waiting for bureaucracy to conclude it can be trying. My experience in reading reports released to the public from Health Canada regarding diet and exercise is they seem to never hit the mark. They have great data, I know because I’ve sifted through pages and pages of it, all available for any Canadian on their web site.
They end up making poor results seem ok. It’s a lowest common denominator philosophy that I just don’t get. In the case of vitamin D, this hasn’t changed, by looking at the recent Stats Canada release of the largest study in Canada in over 30 years (called the Canadian Health Measures Survey) on the status of the health of Canadians, including vitamin D status. Stats Can is often afflicted by the same lowest common denominator virus.. maybe Health Canada sneezed on them.
Here are the results: Vitamin D status of Canadians, 2007 to 2009
- “Deficiency” by 1997 standards is blood plasma having lesser than 27.5 nmol/L of vitamin D. Go this low and you most likely will develop osteomalacia (softening of the bones. Also called rickets in children). An estimated 4% of Canadians are below 27.5 nmoL/l- that’s good news
- “Adequate bone health” at least 37.5 nmol/L. Almost 90% of Canadians met this standard. Good news again, but there is a definite “but”.
- “Optimal health” 75 nmol/L - 65% of the population is below this level. Euphemistically, Stats Can reports this as “35% of the population had levels above 75 nmol/L”
This looks great! So much for the all reports on Canadians not getting enough vitamin D. Only 4% of the population is “deficient” so don’t by vitamin D pills, you don’t need them.
Or do you?
Just to be thorough I checked my calendar and sure enough it isn’t 1997 anymore. A moment please.. calculator.. hey! What? That was 13 years ago! I wonder if anyone has published a paper on vitamin D since 1997. A little tongue in cheekyness there. Hope you don’t mind.
Indeed, yes. Lot’s of studies. In fact much of what we are beginning to understand now about vitamin D was simply not known in 1997. No, Stats Can is not in the dark about the new data, in fact they reference it and give lot’s of detail on the joint US -Canada committee currently tasked with sorting this all out.. it just wasn’t sorted when this data was released on March 23, 2010.
Health Canada and pretty much any Registered Dietician will say that you might need up to 600 IU of vitamin D per day depending on your age, body mass, dietary intake of vitamin D, medications you’re on, and summer sunlight exposure. Health Canada does fully disclose that until new recommendations are made they can only fall back on the old recommendations. OK. Good enough for them, not good enough for me.
Which brings me to my 5000IU per day dosage in the winter. The research shows there’s not really any chance of toxicity at 5000IU per day. Consider this; 20 minutes in the sunshine in summer and your body will make 20,000 IU. Studies show you would need to take 30,000 to 40,000 IU per day for months to achieve toxic levels.
So 5000IU isn’t going to hurt me. Will it help me? I don’t know yet. I’m waiting for my vitamin D results to come back, which by the way takes longer than a Winnipeg winter.
Apparently the labs in Canada that do vitamin D testing are so backed up it could take up to one year to get your results back. Hmm. Seems to be a bit of a rush on the bank there. Public panic? Or are doctors doing do-diligence and testing vitamin D levels in their patients because of the widely reported vitamin D deficiencies in the Canadian population?
Some reports suggest that it could take 3000 to 5000 IU/day to raise vitamin D levels high enough (starting from sub optimal levels) to see maximum benefit in terms of overall health, which in the case of vitamin is:
- Cancer prevention
- Decreased blood pressure
- Reduced risk of cardiovascular disease
- Optimal absorption and use of calcium
- Muscle strength and exercise tolerance
- Balance and coordination (reduces risk of slip and fall in seniors)
- Optimal sleep quality
- Prevention and possible treatment of MS, and more.
What has been discovered is that there are vitamin D receptors in nearly every system of the body, thus vitamin D’s influence on all the above.
This isn’t only about bone health, it’s about our overall health. That’s why saying that 90% of Canadians have adequate vitamin D levels with todays knowledge doesn’t make any sense. Adequate for bone health, yes. But to optimally absorb and regulate calcium vitamin D levels are suggested to be around 80 nmol/L. Cancer prevention and other health outcomes may be better affected by up to 120 nmol/L of vitamin D in our blood. Considering this, nearly all Canadians are deficient in the winter.
- Cancer Canada says adults should take 1000IU per day.
- Osteoporosis Canada says adults should take 800IU per day.
- The Canadian Pediatric Society says pregnant woman should consider 2000 nmol/L/ day.
- You should have your physician test your vitamin D levels. Ask for the 25-hyrdoxyvitamin D test.
- Vitamin D levels are the lowest in March for most Canadians
- A BC study revealed that up to 97% of Canadians become vitamin D deficient in the winter
New information on which new vitamin D level recommendations will be influenced by:
Blood levels of vitamin D and health outcomes:
- 80 nmol/L for optimal absorption and regulation of calcium
- 90 to 124 nmol/L for cancer prevention
- 75 to 95 nmol/L of vitamin D is where parathyroid production is maximally suppressed. Too much parathyroid production (hyperparathyroidism, which is linked to osteoporosis, kidney stones, hypercalcemia (increased calcium levels).
Many studies have shown Canadians to have sub optimal vitamin D levels, with the lowest levels occurring in the late winter or early spring as it takes a winter to work through our vitamin D stores we built up in the summer months. Don’t read that the wrong way, it’s not as though we have enough to last through the winter, we still blow through about 5000IU per day of vitamin D as the big D does all that it does and by the time spring rolls around we’ve already been deficient for a few months, reaching our lowest levels just before we start spending more time outdoors and making our own D.
A note on this, You could stand outside naked in the middle of winter in Canada on a sunny day and you still would not make your own vitamin D. The tilt of the earth changes the angle of the sun and the UV rays we need are filtered out by the atmosphere, at least filtered enough so it doesn’t do us any good.
On the note of filtering rays, any window does the same thing, so does most clothing, and most sunscreen. Clouds filter as well, but not enough to stop vitamin D production (in summer).
Vitamin D counsel does a good job of summarizing all the study references and explaining details about vitamin D. the Vitamin D Society
So that’s why I’m on 5000IU per day. Nearly all Canadians are deficient in the winter: it was winter when I started taking D; 3000 to 5000IU is need to raise levels from deficiency to at least 80 to 90 nmol/L- optimal levels for calcium regulation and cancer prevention, and there is no harm at 5000IU per day. I started with 2000IU on my own accord, then talked to my doctor about whether I needed more. Based on my needs the doc said do 5000IU per day, then we’ll look at my vitamin D test results and re-adjust supplementation accordingly. Needs will vary with age, gender, body mass, medical conditions, and of course actual vitamin D status.