One of the leading nutrients on the forefront of scientific research is vitamin D. Also called the sunshine vitamin, vitamin D is important for immune system support, blood sugar health, and energy.   A deficiency in this essential micronutrient is unknowingly plaguing millions of people worldwide. In order to avoid a vitamin D deficiency, you must take conscious, proactive steps to combat the factors that affect absorption. Vitamin D supplementation is the ideal method for reducing deficiency risk, especially in the winter. Sunlight is also a simple and natural approach for balancing vitamin D levels.
Things That Affect Vitamin D
Factors that affect vitamin D absorption are sometimes easy to overcome; however, as you will read in the following post, factors such as skin color and air quality are far less controllable. Here are some things you should be aware of if you are concerned with keeping your vitamin D levels in check:
The use of sunscreen has been touted as a healthy method for preventing sunburn, skin cancer, and excessive aging of the skin. While this may be true, sunscreen can actually increase the risk for cancer because of its strong blocking action against vitamin D.  Sunscreen typically blocks UVB rays, the rays responsible for activating the production of vitamin D. If you plan on going outside for a long period of time, allow your skin to soak up the rays without sunscreen for at least 15-20 minutes. Then, apply an organic sunscreen to all exposed areas.
Body fat absorbs more vitamin D and acts as a storage center for the nutrient. Having a healthy body fat percentage can be helpful for ensuring adequate vitamin D levels all year round, regardless of whether you are supplementing or not.  Obesity, however, tends to correlate with lower vitamin D status, prompting many health officials to believe that being overweight increases the risk for deficiency. A healthy weight loss plan may reduce the likelihood of vitamin D deficiency, along with other health conditions.
3. Skin Color
Melanin, the substance that gives skin its pigment, competes for UVB to produce vitamin D. That means the more melanin you have (or the darker your skin color), the greater chance you will suffer from deficiency.  Dark-skinned people need more time in the sun, or more International Units (IUs) of vitamin D from supplements, to raise vitamin D blood levels into a healthy range.
4. Air Quality
Organic particles from the burning of wood, fossil fuels, and other materials are scattered in outdoor air and are absorbing UVB. This makes it difficult to achieve proper vitamin D absorption from sunlight alone. Living in an urban environment with air that is heavily polluted also presents issues for vitamin D production.  If this is your situation, it may be advised to supplement with vitamin D while having your doctor monitor your vitamin D status.
During the winter, UVB light exerts less impact on the earth’s surface. This is especially true the further away you get from the equator. Supplementation is often warranted during the winter to ensure healthy levels no matter how far from the equator you are. The short daylight hours combined with the wearing of long sleeves and pants also limits exposure to vitamin D-producing rays.
One Final Thought
In order to know whether or not you need to supplement with vitamin D, you must have your blood levels checked by your doctor. Ask for a 25 hydroxyvitamin D test to determine your status. Your doctor should be able to advise the appropriate supplementation amount needed for reaching a healthy level. The Vitamin D Council recommends a healthy vitamin D level of 40-80 ng/mL.
What do you do to handle your vitamin D levels? Do you supplement? We’d love to hear your thoughts about this crucial nutrient!
- Cynthia Aranow, MD. Vitamin D and the Immune System. J Investig Med. Aug 2011; 59(6); 881-886. doi: 10.231/JIM.0b013e31821b8755.
- George PS, Pearson ER, Witham MD. Effect of vitamin D supplementation on glyaemic control and insulin resistance: a systematic review and meta-analysis. Diabet Med. 2012 Aug;29(8):e142-50. doi: 10.1111/j.1464-5491.2012.03672.x.
- Debska O, Kaminska-Winclorek G, Spiewak R. Does sunscreen use influence the level of vitamin D in the body? Pol Merkur Lekarski. 2013 Jun;34(204):368-70.
- Arunabh S, Pollack S, Yeh J, Aloia JF. Body fat content and 25-hydroxyvitamin D levels in healthy women. J Clin Endocrinol Metab. 2003 Jan;88(1):157-61.
- Shoenfeld N, Amital H, Shoenfeld Y. The effect of melanism and vitamin D synthesis on the incidence of autoimmune disease. Nat Clin Pract Rheumatol. 2008 Feb;5(2):99-105. doi: 10.1038/ncprheum0989.
- Hosseinpanah F, Pour SH, Helbatollahi M, et al. The effects of air pollution on vitamin D status in healthy women: a cross sectional study. BMC Public Health. 2010 Aug 29;10:519. doi: 10.1186/1471-2458-10-519.
†Results may vary. Information and statements made are for education purposes and are not intended to replace the advice of your doctor. If you have a severe medical condition or health concern, see your physician.