How Much Vitamin D Do You Get From The Summer Sun?

By Teresa Wagner, RD, LD
August 17, 2021

vitamind-sun.jpgI know, I know we’ve been harping on the vitamin D thing since COVID began over a year ago. Let me ask, have you had your levels checked at your latest doctor’s appointment?  Do you get enough vitamin D from the sun or diet? Have you started taking vitamin D3? Well, this is your lucky season if you haven’t taken proactive steps to ensure your vitamin D levels are optimal! While there are a few different reference ranges for vitamin D, the recommendation of 50-80ng/dL seems to be the sweet spot and the level that most of my clients say they feel their best.

 

ng/dL

Deficient

< 15

Insufficient

15-30

Minimum Target

30

*Therapeutic

40-70

Upper Limit

100

Excessive

> 100

            *The Vitamin D Council recommends a level of 50-80ng/dL year-round. (1)

What causes vitamin D deficiency?

There are a few factors that may interfere with your ability to get your levels to optimal.

  • Living in Minnesota (or if you live anywhere north of Atlanta and 33.7 latitude!) – We just don’t get enough sun, in fact even on sunny spring and fall days the sun’s angle isn’t high enough for your skin to absorb the UVB rays.
  • Dark skin – The darker the skin the higher the melanin.  Melanin works as a natural sunscreen which is great for the prevention of skin cancer and wrinkles, not so great for the production of vitamin D.
  • Obesity – Vitamin D is a fat-soluble vitamin and is happy to stick around in your fat cells rather than circulate around your body doing its various jobs. (2)
  • Age – As we age it becomes more of a challenge for the body to convert vitamin D into its most usable form.

How much vitamin D can you actually get from the sun?

With all these variables in place it can be difficult to say how much sun a person needs in order to make adequate amounts.  A young, light-skinned, lean person will make vitamin D more readily than an older, dark-skinned, overweight person.  Light-skinned people can usually tolerate 10-20 minutes basking in the sun while dark-skinned folks could handle 90-120 minutes. 

The other variable is your attire! To give you an idea of some numbers and ranges, using the timing we just mentioned above, here are some estimates for getting adequate D from the sun on a clear, sunny Minnesota day (45° latitude) between May and September, 10:00am-2:00pm, no sunscreen with the goal of around 2000 IU per day (3):

  • 70% skin exposure (swimsuit only) 1400-2800 IU
  • 46% skin exposure (shorts and t-shirt) 800-1600IU
  • 5-12% skin exposure (hands and face) 100-200 IU

Please don’t try to make up for less skin exposure with more time in the sun. At this amount of time, a person is not likely to become burned.  The goal is exposure to UVB rays, so if your skin turns pink that’s a sign of too much sun for that area of skin and can lead to skin cancer with overexposure. 

Could you get too much vitamin D?

While the possibility of Vitamin D toxicity is relatively low from sun exposure, we can have levels too high if we continuously supplement.  The best way to protect yourself from vitamin D toxicity is to have your blood levels tested and supplement according to those numbers.  Early spring is the best time of year for vitamin D testing due to several months of low/no sun exposure.

Another way to protect yourself from vitamin D toxicity is to eat foods with the other fat soluble vitamins (real food for the win yet again!).  The body does a wonderful job of protecting itself when the right nutrients are on board. The fat-soluble vitamins A, D, E and K are great at keeping each other in check.  Foods rich in these vitamins tend to be in higher fat foods, like beef liver, natto, salmon, herring, nuts, seeds and avocado. Leafy greens, orange and red colored vegetables and fruits, and some mushrooms are sources as well.

After all this how to get vitamin D, here are a few reasons why:

  • Immune Function – Vitamin D triggers an anti-microbial response that fights off pathogenic foreign invaders, aka things that can make you sick.
  • Strong Bones and Teeth – Vitamin D works in tandem with calcium and vitamin K2. Vitamin D plays a crucial role in the absorption of calcium into the intestines and blood.  Vitamin K2 then takes the calcium from there and deposits it into the bones and teeth. (4)
  • Prevention of Heart Disease – If vitamins D and K2 are low, excess calcium may not be absorbed into the bones and can end up accumulating in your arteries leading to blockages. (4)
  • Mood – Vitamin D activates genes that regulate the release of our feel-good chemicals, serotonin and dopamine.  The vitamin D receptors in the brain are located in the same regions associated with depression. (5)
  • Cancer Prevention - adequate amounts of vitamin D could be associated with a lower risk of colon, breast, prostate and ovarian cancers. (6)

Would you benefit from supplementing vitamin D3?

If you are like much of the population where exposure to direct sunlight is either not possible most days of the week or you have been advised to stay out of the sun, supplementing with 2,000-5,000 IUs of vitamin D3 during the summer months may be beneficial to you.  More recently I have been recommending my clients take a D3K2 supplement in place of their usual D3.  K2, like D3, is difficult to get from your diet unlike its sister vitamin, K1, found abundantly in green vegetables.  Benefits to taking K2 with your vitamin D3 are for bone and cardiovascular health as discussed earlier.

Our sister company, NutriKey, has a Vitamin D3 1000, Vitamin D3 5000, and a Vitamin D3 with K2 to make it easy for you to get the dose juuuuust right for what your individual body needs. There’s even a D3 with K2 in a liquid form making it easy to tailor your dose and for the kiddos! 

The summer is a great time to get FREE vitamin D so go outside and soak it up when you can (using some caution based on the guidelines above). When you can’t, take some supplemental D3 to keep your levels in the optimal range.  Your body will thank you for it!

For more information, check out these resources:

Resources:

  1. Guilliams, Thomas (2011) Technical Report: Target Serum Levels and Optimal Dosing of Vitamin D. Point Institute
  2. Vranić, Luka et al. “Vitamin D Deficiency: Consequence or Cause of Obesity?.” Medicina (Kaunas, Lithuania) vol. 55,9 541. 28 Aug. 2019, doi:10.3390/medicina55090541
  3. Webb, A.R. and O. Engelsen (2006) Calculated Ultraviolet Exposure Levels for a Healthy Vitamin D Status. Photochemistry and Photobiology. 82(6), 1697-1703.
  4. Maresz K. Proper Calcium Use: Vitamin K2 as a Promoter of Bone and Cardiovascular Health. Integr Med (Encinitas). 2015 Feb;14(1):34-9. PMID: 26770129; PMCID: PMC4566462.
  5. Greenblatt, J. "Psychological Consequences of Vitamin D Deficiency." Psychology Today (2011). 
  6. Garland, Cedric F et al. “The role of vitamin D in cancer prevention.” American journal of public health vol. 96,2 (2006): 252-61. doi:10.2105/AJPH.2004.045260

About the author

Teresa is a licensed dietitian at Nutritional Weight & Wellness. As a mother of three children and avid runner, Teresa knows that good nutrition is essential for energy and well-being. She also sees first-hand the impact food choices have on her children’s behavior, moods and happiness. Teresa is a registered and licensed dietitian through the Minnesota Board of Nutrition and Dietetics. She received her B.S. in dietetics from the University of Wisconsin-Stout and completed her dietetic internship at Indiana University School of Health and Rehabilitation Sciences. She worked as a clinical dietitian for the Richard L. Roudebush VA Medical Center in Indianapolis.

View all posts by Teresa Wagner, RD, LD

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