It’s a vitamin … it’s a … hormone?!
Vitamin D is one of the fat soluble vitamins (the others being vitamins A, E and K). This means that our body can actually store it.
It also acts like a hormone (a special chemical messenger) in the body!
Why is vitamin D important?
Vitamin D is probably most well known for its function in improving calcium absorption in the gut and helping regulate the amount of calcium and phosphate in the blood for optimal bone health.
To read more about calcium on a plant based diet, click here.
In addition to these things, vitamin D plays an important role in your balance and muscle movement, immune function, cell growth and regulating inflammation. Research has also been done linking vitamin D’s role in preventing and managing certain cancers, heart disease, diabetes, multiple sclerosis (MS) and rheumatoid arthritis (RA).
How much vitamin D do we need?
The amount of vitamin D needed per day and the ideal level of vitamin D in your blood for optimal health is still up for debate. Depending on who you talk to, you may get a different answer.
Many experts recommend 1000-2000 IU per day, particularly in the winter months (October to March), when our bodies are less efficient at making vitamin D from the sun, no matter how much you bask in its rays!
Where do we get vitamin D?
One of the greatest things about this vitamin is that we can make it on our own through sun exposure!
As mentioned above, how well your body does this is affected by the time of the year. In Canada, we are not making adequate vitamin D from sun exposure through the months of October to March.
During the summer months, all it takes is 10-15 minutes on the face and arms or legs to make your vitamin D. Darker skinned individuals need longer in the sun, more like 20-30 minutes.
Factors that influence your ability to make vitamin D
- Your age
- The older you get, the less efficient your body is at producing vitamin D.
- Skin colour
- Darker skinned individuals are less efficient producers compared to lighter skinned individuals. This is why if you have darker skin, you need to be in the sun longer to produce the same amount of vitamin D.
- Wearing sunscreen, although sun safe, prevents your skin from making vitamin D.
- Air pollution
- Smog decreases the strength of the suns rays.
Food Sources of vitamin D
Vitamin D is found naturally in very few foods. Most of these foods are animal sources like egg yolks, fish, liver and fortified dairy.
The most commonly fortified plant based beverages are orange juice and store bought dairy alternatives. For plant based dairy alternatives, vitamin D2 is the form of vitamin D used for fortification.
Vitamin D2 versus D3
Vitamin D2 has historically been the only ‘vegan friendly’ vitamin D. It is derived from plants.
Vitamin D3 is derived from animal sources (lanolin , which is wool). But, D3 can also be made by lichen, a plant-based organism.
Vitamin D3 has long been promoted as the form of vitamin D most efficient at raising blood levels and preventing deficiency.
We now have research that shows vitamin D3 raises blood levels of vitamin D more effectively when given in large doses compared to vitamin D2, BUT, the two seem to be pretty equal at doing the job when given at doses less than 4000 IU per day.
Plant derived vitamin D3 is now readily available!
To supplement or not to supplement
My recommendation is that plant-based or not, you will benefit from supplementing with vitamin D (1000-2000 IU) daily, particularly in the months of October to late March.
If you have questions about starting a vitamin D supplement, talk with your primary care provider or dietitian!