Vitamin D is a nutrient required by our bodies. It promotes the absorption of calcium and phosphorus (two minerals important for bone health) from the foods we eat. This vitamin is also important for a healthy immune system and muscle strength¹. You may know of vitamin D as the “sunshine vitamin” – this is because our bodies are capable of producing it when our skin is exposed to UVB rays from the sun. We can also obtain it from our diet².
The amount of the sunshine vitamin that you make depends on your skin colour and age – those with darker skin and the elderly make less from the sun. Time of year and location are also important factors¹. For example, during July in Boston, MA, someone with skin type I needs to spend 4 minutes under the sun at noon to get 1000 IU, whereas someone with skin type III needs to spend 7 minutes³. Exposing our skin to the sun puts us at risk of developing a sunburn, but the amount of time we can spend in the sun before this happens varies based on skin type, environmental setting, and the UV index. If the amount of time you need to spend in the sun to get enough vitamin D exceeds your safe sun time, sunshine isn’t your best bet. Sun Index
can help you monitor your safe sun time.
Like other nutrients, different groups of people need different amounts of vitamin D to stay healthy. For instance, infants under one year old need to consume 400 IU per day, whereas individuals over the age of 70 need to consume 800 IU per day, assuming they experience minimal sun exposure⁴.
Even though our bodies can make this vitamin naturally, overexposure to UVB rays puts us at risk of developing premature aging and skin cancer. The American Academy of Dermatology recommends that we get our vitamin D from dietary sources and/or supplements, rather than by exposing our skin to UVB rays⁵. Some dietary sources include swordfish, tuna, sockeye salmon, and vitamin D-fortified milk or orange juice. Getting enough from your diet can be a challenge, especially if you have certain food allergies or intolerances, or if you are vegetarian, ovo-vegetarian, or vegan⁴. Taking a supplement can help ensure that you reach the recommended intake every day.
- Johnson, L. E. (n.d.). Vitamin D. Retrieved July 8, 2016
- Linus Pauling Institute Micronutrient Information Centre. (2014). Vitamin D. Retrieved July 8, 2016
- Terushkin, V., Bender, A., Psaty, E. L., Engelsen, O., Wang, S. Q. and Halpern, A. C. (2010). Estimated equivalency of vitamin D production from natural sun exposure versus oral vitamin D supplementation across seasons at two US latitudes. Journal of the American Academy of Dermatology, 62(6):929.e1-9. Retrieved July 15, 2016
- National Institutes of Health. (2016). Vitamin D. Retrieved July 8, 2016
- American Academy of Dermatology and AAD Association. (2009). Position Statement on VITAMIN D. Retrieved July 8, 2016