Do you find yourself feeling depressed during the long and dark winter season? Have you ever noticed why your mood is generally better on sunny days? The explanation behind this is relatively simple. If you were to step outside in the middle of July at 10 AM with no sunscreen for 15 minutes, you would be able to produce roughly 1000 IU of vitamin D3 (this will vary depending on your skin pigment, weight, age). Under ideal conditions, the human body is capable of producing upwards of 10000 IU from about half an hour in the sun. Now consider this: the minimum daily recommended dose is 600 IU and the Vitamin D Council suggests that 50 ng/ml (a measurement of the amount of serum vitamin D in the body) is the minimum acceptable level. Despite this, the Food and Nutrition Board notes that 97 percent of Americans have a vitamin D level that falls into the range of 20—30 ng/ ml and a study by Stats Canada indicates that most Canadians are also deficient in D3, especially during the winter. Here are some common risks linked to low vitamin D levels:
- Insulin resistance and poor blood sugar regulation
- Poor immune function
- Poor cardiovascular health
- Decreased muscular mass, strength and power development
Although vitamin D3 toxicity is possible, it is impossible to attain from sun exposure alone. In fact, a healthy person would have to take upwards of 50000 IU per day, every day for several months. Though it is possible to get adequate levels of vitamin D3 from sunlight exposure alone, this can be difficult or impossible, depending on the season and your geographical location. Despite the fact that vitamin D is fat soluble, meaning your body can store extra amounts of it, we simply are not getting enough! In my opinion, it is not only safe but ideal for a relatively healthy person to be getting at least 5000 IU of D3.
Here are some effective ways to increase your D3 levels:
- Sun exposure
- Cod liver oil
- Organ meats
Vitamin D deficiency is potentially deadly yet it is extremely common. Have your blood work done to be sure. Make sure to go outside and get lots of direct sun exposure when it is possible, supplement when it is not and improve your health drastically!
Salehpour, A., et al. A 12-Week Double-Blind Randomized Clinical Trial of Vitamin D3 Supplementation on Body Fat Mass in Healthy Overweight and Obese Women. Nutrition Journal. 2012. 11, 78.
Carrillo, A., et al. Impact of Vitamin D Supplementation During Resistance Training Intervention on Body Composition, Muscle Function, and Glucose Tolerance in Overweight and Obese Adults. Clinical Nutrition. 2012. Published Ahead of Print.
Rock, C., Emond, J., et al. Weight Loss is Associated with Increased Serum 25(OH) D in Overweight or Obese Women. Obesity. 2012. Published Ahead of Print.
Lamendola, C., Arial, D., et al. Relations Between Obesity, Insulin Resistance, and Vitamin D. American Journal of Clinical Nutrition. 2012. Published Ahead of Print.
Von Essen, M., Kongsbak, M., Schjerling, P., Olgaard, K., Odum, N., Geisler, C. Vitamin D controls T cell antigen receptor signaling and activation of human T cells. Nature Immunology. 2010. 11, 344–349.
Vijay, G., Milone, C., Cody, M., McCarty, F., Want, Y. Serum vitamin D concentrations are related to depression in young adult US population: the Third National Health and Nutrition Examination Survey.International Archives of Medicine. 3(1), 29.
Chen, G., Kim, S., King, A., Zhao, L., Simpson, R., Christensen, P. CYP24A1 Is an independent prognostic marker of survival in patients with lung adenocarcinoma. Clinical Cancer Research. 2011. 17(4), 817-26.
Holick, MF. High prevalence of vitamin D inadequacy and implications for health. Mayo Clinic Proceedings. 2006. 81(3), 353-73.
Ward, K., Das, G., Berry, J., Roberts, S., Rawer, R., Adams, J., Mughal, A. Vitamin D status and muscle function in post-menarchal adolescent girls. The Journal of Clinical Endocrinology and Metabolism. 2009. 94(2), 559-563.