VITAMIN D

WHY YOU NEED VITAMIN D THIS WINTER




With the passing of the autumn equinox, there has been a sudden flurry of sightings of Pentictonites wearing boots and sweaters, and the smell of pumpkin spice lattes is in the air. 


This is a good time to consider why vitamin D supplementation is essential for everyone from now until late spring. 


While vitamin D is best known for its role in bone health and the prevention of osteoporosis, there are multiple other reasons why vitamin D is essential for optimal health. Low levels of Vitamin D are known to be associated with increased risk for colon cancer, breast cancer, prostate cancer and ovarian cancer. There are also links with multiple sclerosis, reduced muscle strength, muscle stiffness, higher LDL cholesterol and triglyceride levels, and macular degeneration. Vitamin D also affects cell growth in the body and has roles in neuromuscular and immune system function as well as helping to decrease inflammation.

The long Canadian winters mean we are naturally losing our vitamin D stores, making it easier to fall victim to colds and flu. This is because vitamin D is essential for activating the quick response part of our immune system which helps us deal with exposure to  new infectious agents. There are also studies that have shown that people get less wintertime respiratory infections with higher serum levels of vitamin D. 

Vitamin D3 (or cholecalciferol) is the naturally occurring form that is present in most supplements and is identical to the vitamin D3 made in your skin after being exposed to direct sunlight (UVB radiation). Food sources include fatty fish, beef liver and egg yolks but it is not possible to obtain sufficient vitamin D through diet alone. 

Vitamin D2 (ergocalciferol) is a synthetic form made from irradiated mushrooms. This is often preferred by vegetarians and vegans as vitamin D3 is usually obtained from the lanolin from sheep wool. The problem with vitamin D2 is that it is less effective in raising blood levels and is not effective for as long as vitamin D3.

In summer, we are able to make between 10 000 and 25 000 IU (international units) in half the time it takes for the skin to turn pink. This might be 15 minutes for a fair skinned person, and up to 2 hours for someone with dark skin and dark eyes. You do not need to tan or burn to get this benefit. However, during winter in the Okanagan (and indeed, all of Canada) - the angle of the sun is too great for most of the day, so UVB rays are blocked and it is not possible to make vitamin D in the skin. So, basically, if your shadow is longer than you are tall, you cannot make vitamin D!


Do you need to get tested and how much should you be taking?


The simple answers to these questions are - Yes! and “It depends..”

The Mayo Clinic recommends testing vitamin D levels - both to establish the need for vitamin D supplementation and to guide appropriate treatment. The main concern cited, is to avoid under-medication (not overdose). One of the reasons for this is that there are large variations between individual absorption with some people having a polymorphism (gene variation) which means they absorb far less than the general population. Being overweight and obese also decreases your available vitamin D as it is stored in adipose tissue (fat cells) and is therefore not available for use in the body.

Unfortunately across Canada,  at least 6 provinces, including BC, have stopped paying for vitamin D testing unless it is already known that the patient suffers from a vitamin D deficiency-related disease such as osteoporosis. Yes that’s right, you can’t be tested unless we already know you are probably deficient! 

Well, you can be tested, but in BC be ready to pay the $65 fee unless you are lucky enough to have your rheumatologist order it, then the test is free to the patient. The BCMA Guidelines recommend against routine testing or screening for vitamin D deficiency  and against testing levels during vitamin D supplementation. To educated physicians, this makes as much sense as guessing that one’s patient has a thyroid problem, then starting them on thyroid medication without checking their levels and also guessing at the starting dose.

The current reference range is 75 - 200nmol/L.  Having a “normal” level, as defined by the reference range, does not necessarily mean this is optimal for health or prevention of multiple diseases discussed. As far as supplementation goes, this remains controversial despite no cases of vitamin D toxicity ever being recorded even in people taking  40 000IU a day. Why then, are the medical authorities still recommending “routine doses” ranging from 400 -1000 IU?

As stated, individual needs vary hugely, with some people maintaining adequate levels at doses as low as 1000 IU daily and others needing 10 000IU or more per day. For people taking the higher doses, these can also be given weekly or monthly. Ideally, work with your doctor, check your levels every 3 months to establish your ideal dosing, and remember, even this will vary hugely from summer to the end of winter.

People with the highest levels of vitamin D are less likely to get cancer, dementia, heart disease, osteoporosis, autoimmune diseases including rheumatoid arthritis and multiple sclerosis, diabetes and certain eye conditions than people with the lowest levels. Isn't it sad that our health authorities choose to save the several hundred dollars it would cost per person to establish optimal vitamin D levels, but are then happy to spend hundreds of thousands to treat the cancer, dementia etc, that may have been preventable?