Tuesday, February 4, 2014

Got Sunshine? A Primer on Vitamin D

There is barely any sunshine to be had around here. And when it is sunny, it's too cold to go outside anyway. If, like me, you are in a climate that is woefully absent of the sun's rays, you might need a vitamin D supplement.

"It's been over half a decade since the Canadian Cancer Society put vitamin D on everyone's minds by increasing their recommendation to 1,000 IU per day during the low-sun winter months," says registered nutritionist Emily Kennedy. "Yet many people still don't know enough about this hormone-like vitamin."

How much vitamin D do I need?

The National Osteoporosis Foundation recommends that adults under age 50 get 400 to 800 IU of vitamin D every day and that those 50 and older get 800 to 1,000 IU of vitamin D every day. 

"But your doctor or naturopath may recommend more depending on your blood levels," says Kennedy. "Look for a naturopath who has a nutritionist on staff to assist with meal planning and lifestyle tips to make dietary changes easier."

Why is it so important to have Vitamin D, especially in winter?

Chemically known as cholecalciferol, vitamin D has been linked to lower rates of heart disease, diabetes, MS, osteoporosis, rickets in children, skin inflammation (ie. psoriasis), depression and other mood disorders – especially seasonal affective disorder, aka SAD.

"If you're a vegan, you're at low risk for heart disease and diabetes, but you may be at greater risk for osteoporosis and mood disorders if you're not careful about your food choices and supplementation," says Kennedy. "Seasonal affective disorder has a well-researched link to vitamin D and UV light exposure levels. It can also be a result of a the nutrient-devoid Standard American Diet, another SAD state to be in."

Why is sunshine my friend?

"Just from being in the sun, your body can produce 10,000 to 25,000 IU of vitamin D in just a little under the time it takes for your skin to turn pink," says Kennedy. She notes that just how much vitamin D your body produces from sun exposure depends on the time of day, where you live and the pigmentation of your skin. "Very fair-skinned people need about 15 minutes, but a dark-skinned person may need a couple of hours to get maximum synthesis."

The time of day is a factor too. "The shorter your shadow is, the more vitamin D you can make from sun exposure," says Kennedy. "Try to get out in midday when the sun is high in the sky, and expose a large area of your skin, such as your back, rather than a small area such as your face or arms."

But what if it isn't bikini weather where you're at? Well, you can get vitamin D from foods. According to the Canadian Nutrient File, the top 5 foods for vitamin D are burbot (loche fish) liver, Artic char with skin, halibut (Greenland), carp and cod liver oil. Yum. "Next in line is eel," points out Kennedy. "See a trend? Not commonly consumed foods, even for the most nutrition-conscious, and not a single vegan option. This is why supplementation is so important."

What form of vitamin D should I take?

"Vitamin D3 is the most common and best form of vitamin D to take," says Kennedy. "It is made by exposing a certain type of cholesterol to UV rays (just like the natural process in our skin). Other forms of vitamin D, like D2, come from mushrooms and are not that well absorbed." If you are vegetarian or vegan, look for a vegan vitamin D caplet, as many supplements contain lanolin or fish oil.

What should my specific level of supplementation be?

Everyone's requirement for vitamin D is a little different depending on age, skin pigmentation, level of sun exposure and health status. "It is possible to overdo vitamin D and upset the balance of other fat-soluble vitamins like vitamin K," says Kennedy.  "Seek the advice of a health practitioner who can evaluate your diet and health history, look for signs of deficiency or order blood work."

Emily Kennedy, MSc RHN, is a registered nutritionist who works at medical and naturopathic clinics in the North York and Thornhill, Ontario areas. She is a part-time vegan, full-time personal health coach. Learn to eat intelligently. www.emilykennedy.ca


  1. Great Post! Many People need more Vitamin D ,especially in the Winter Time :)


    1. Now I just have to remember to keep taking it! :)

  2. Love this! I have to take tons of supplements to make up for my variety of allergies-- vitamin
    D is a must & now I'll be on the look out for D3 specifically!!

    1. I used to take lots of supplements but I got tired of it. Now I just take B12 and D. For the moment anyhow. ;)

  3. Please don't hate me but I was just thinking (literally when I woke up) that I needed to get outside in the sun today for some vitamin D. We've been graced with it this week however I don't know how long it will last.

    1. I don't hate you Wendy, but I certainly would like to visit you right now. In fact, the picture I used above was taken in Florida. We have another snow day here. School buses cancelled, the whole bit...sigh.

  4. Great post! I do take vitamin D year round - but have wondered how much I SHOULD be taking.. Thanks for the info :)

    1. Thank you! I take a little bit more than my doctor recommends. I'm impatient like that. ;)