Often referred to as the “sunshine” vitamin, our body can actually produce vitamin D from ultraviolet-B (UVB) radiation hitting our skin from the sun’s rays. However, results from studies have shown that Canadians are at a higher risk of deficiency, especially in the winter, as shorter days and less time spent outside during peak sun hours, significantly decrease our body’s natural production. 32% of Canadians were shown to have levels below 50 nmol/L, a cut off known to be associated with higher risk of impaired bone growth and osteoporosis. Vitamin D is best known for keeping our bones healthy, but also has a critical role in almost every single area of our health, and integral to regulation of over 2000 genes within our body. Deficiency can have significant negative impact on mood, hormone production, immune function, bone health, autoimmune illness and blood sugar management.. the list goes on and on! Wondering what your vitamin D status is and if you’re getting enough? Let’s shine some light on the basics:
Recommended Dietary Allowance (RDA)
RDA’s have been established by Health Canada for many different vitamins and nutrients, and by definition is the average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%-98%) healthy people. Requirements vary among different age groups, and whether you are pregnant or breastfeeding.
Infants (0-12 months): 400 IU
Children & adults (1-70 years): 600 IU
Adults (>70 years): 800 IU
Pregnancy/Lactation: 600 IU
Factors influencing absorption:
Some factors may predispose you to be at a greater risk for vitamin D (beyond that of just living in the great white north!):
- Higher BMI
- Limited sun exposure
- living above 37° north or lower than 37° south of the equator
- indoor occupation
- full-coverage clothing, hats and sunscreen use
- Darker skin pigment
- Non-supplement users
- Dairy free or non-fish eaters
- Intestinal disorders limiting absorption of fat
- Kidney or liver disease reducing conversion of vitamin D to its active form
- Certain medication (steroids, laxatives, cholesterol-lowering drugs
Can I get enough through food & sun?
Even though our body has the ability to produce its own vitamin D, actual sun-induced vitamin D synthesis widely varies from person-to-person, and is hugely influenced by season, time of day, latitude, altitude, air pollution, skin pigmentation, sunscreen use and aging. Taking into account all these factors, there is no specific length of time or skin exposure recommendation that will be right for everyone. In addition, although vitamin D is vital to our health, we also want to balance our need for this VIP vitamin, and what increased sun exposure means for our skin health. Excessive exposure to UVA and UVB radiation can increase risk for skin cancers, and also accelerate appearance of wrinkles and premature aging.
Consumption of vitamin D rich foods can help make a dent in our RDA’s, but even with a diet full of oily fish, eggs and fortified foods (dairy products, alternative milks, orange juices & cereals) – it still often isn’t enough! Most people require vitamin D supplementation to meet even the basic RDA for their age group, and depending on individual health status, may actually require much higher dosing to reach sufficient blood levels of vitamin D.
Test, don’t guess!
Vitamin D serum levels measured in nmol/L (tested through blood) is the standard for assessing whether values are considered sufficient.
Levels considered adequate for healthy bones for most people: 50nmol/L and above. Approximately 68% of Canadians meet this value, with the largest portion of this percentage being children aged 3-5 years old.
Levels considered deficient: less than 30nmol/L. This encompasses about 10% of Canadians, with deficiency being more prominent in winter months.
Wondering where your levels measure up, and if you are getting enough to support your most optimal health? The safest and most accurate way is to test your individual levels through blood. As with any supplementation, there is risk linked with both taking too little, and too much. Vitamin D toxicity can occur with overdosing (there definitely can be too much of a good thing!), and can result in long-term kidney and bone damage. As always, talk to your Naturopathic Doctor before starting any new supplement to figure out the ideal dosing for you and your unique health history.
Naturopathic Doctor
