Vitamin D: Getting Benefits from the Summer Sun

Summer is here and with it comes trips to the pool, the beach, and spending more time in the sun. We've been told for years that we need to apply sunscreen to protect our skin from the harmful rays of the sun. This is true, but we often take this too far, covering our bodies with sunscreen to such an extent that we don't get the benefits of vitamin D, which we receive primarily from sunshine.

Vitamin D deficiency is now so widespread that it is considered a pandemic. [1] Nearly everyone is deficient in vitamin D and needs to be taking steps to monitor and ensure that their vitamin D levels stay within the optimal range. The benefits of optimizing your vitamin D levels are worth spending a few minutes soaking in the sun or taking a vitamin D supplement if needed.

So, what are the benefits of vitamin D?

Bone Health

Vitamin D is crucial to bone health. Without vitamin D you only absorb 10-15% of the calcium you take in through your diet. In fact, vitamin D deficiency is a precursor for both osteopenia and osteoporosis and it increases your risk of bone fractures. [2] Vitamin D may be even more important than calcium for ensuring bone health, especially since Americans are more likely to be deficient in vitamin D than they are in calcium. [3]

Thyroid Health

You might be surprised to know that vitamin D is needed to ensure your thyroid functions properly. I work with clients to help them naturally balance their hormones, including their thyroid hormones.  Almost every client I've seen with thyroid problems has had a vitamin D deficiency. Studies have linked vitamin D deficiency with Hashimotos, which is the most common cause of hypothyroidism in the United States. [4]

Cancer Prevention

If you know anything about me, you know that I am passionate about cancer prevention. If you are too, then you'll be very interested in learning that there are over 60 studies linking vitamin D deficiency to increased cancer risk. [5] Recently I considered volunteering for one of these studies that was looking at whether higher levels of vitamin D would decrease breast cancer risk in women who were at high risk for the disease. I decided not to participate in the study because the control group was going to be given a dose of vitamin D that I felt was insufficient to maintain my health. Instead I did my own research on vitamin D and cancer to find out what was already known.  

One of the most interesting studies I found was a computer-based prediction model that shows that optimizing vitamin D and calcium levels could prevent 58,000 new cases of breast cancer and 49,000 new cases of colon cancer in the U.S. and Canada annually. Researchers in this prediction model suggest that vitamin D may be able to halt cancer's progress in the early stages. [6] Wow, that's certainly a motivator to get your vitamin D level checked and work towards keeping it in the optimum range!

Optimal Levels

Getting your vitamin D level checked is as simple as asking your doctor to include this in your next blood test. There are varying opinions on what the optimum levels for vitamin D are. Most lab results list normal ranges of vitamin D (25-OH, D3) from 30-100 ng/ml, but many experts suggest that the optimal range for vitamin D should be between 50-100 ng/ml. A vitamin D level of 50 ng/ml or higher is associated with a 50% lower risk of breast cancer and colorectal cancer. [7,8]  

Sun or Supplement?

Is sunshine enough to keep your vitamin D levels in the optimal range? It depends. There are a lot of factors that determine how much sun you need to produce adequate levels of vitamin D. The time of year, the angle of the sun, the color of your skin, and your proximity to the equator all contribute to how much vitamin D your skin is able to produce from the sun.  Plus there is the consideration of skin cancer that you don't want to ignore when determining how much sun exposure is enough before you should apply that sunscreen.

It’s best to test your vitamin D levels periodically. If you are close to the optimal range, you may be able to maintain these levels by ensuring a small amount of daily sun exposure. If your vitamin D levels are low, you may benefit from getting outdoors AND getting a boost with a vitamin D supplement. It’s always important to talk to your doctor before taking supplements, so schedule an appointment with your doctor for a vitamin D test, and in the mean time, get outside and get a bit of fresh air and sunshine!

References 

1. Am J Clin Nutr April 2008 vol. 87 no. 4 1080S-1086S  https://pubmed.ncbi.nlm.nih.gov/18400738/

2. N Engl J Med 2007;357:266-81  https://www.nejm.org/doi/full/10.1056/nejmra070553

3. Journal of the American Medical Association (2005;294:2336-41)  https://pubmed.ncbi.nlm.nih.gov/16278362/

4. Choi YM et al. Low Levels of Serum Vitamin D3 are Associated with Autoimmune Thyroid Disease in Pre-Menopausal Women. Thyroid, 2013.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3993051/

5. The Role of Vitamin D in Cancer Prevention, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1470481/

6. Vitamin D for Cancer Prevention: A Global Perspective, https://www.sciencedirect.com/science/article/abs/pii/S1047279709001057

7. Circulating 25-hydroxyvitamin D levels and survival in patients with colorectal cancer J Clin Oncol. Jun 20 2008: 2984-2991.  

8. Anticancer Research February 2011 vol. 31 no. 2 607-611