Chronic Illness Wellbeing
How to Improve Vitamin D Deficiency
August 5, 2019

Previously, I’ve explored what role vitamin D deficiency plays in the development and progression of autoimmune conditions, and with just how important vitamin D is in maintaining optimal immune health, it seemed like a good idea to share about how to improve vitamin D deficiency and if you’re not yet deficient, how to increase your vitamin D levels and reduce your chances for developing a deficiency in the first place.

Why Vitamin D is Important

It’s probably useful to again explain what exactly vitamin D is and why it is so important to your overall health. Vitamin D is a prohormone belonging to a category of fat-soluble vitamins. It is referred to as the ‘sunshine vitamin’ because the primary source of vitamin D is from bare skin being exposed to the sun.

As a fat-soluble vitamin, vitamin D is stored in the liver and fatty tissues in the body. When you are exposed to the sun, UV-B rays hit your skin and convert a naturally occurring skin cholesterol, 7-dehydrocholesterol, into pre-vitamin D, and then into usable vitamin D3. (1

Vitamin D plays a crucial role in the body and vitamin D deficiency has been linked to a number of diseases in the body, including:

  • bone disease
  • cancers
  • cardiovascular disease
  • autoimmune conditions, like multiple sclerosis, rheumatoid arthritis, and type 1 diabetes mellitus (2)

How to Supplement and Ensure You Have Enough Vitamin D

According to the most recent data available, nearly 42% of the U.S. population is deficient in vitamin D. (3) Due to a number of factors, including higher rates of obesity, poor diet, and more sedentary lifestyles with minimal outdoor time, it is estimated by many that that figure could actually be much higher. 

While you could have a blood test performed to determine if you are deficient in vitamin D, may be an even better approach is to simply intentionally manage how much vitamin D you’re getting through sun exposure and dietary sources, and supplement as needed. So let’s go through the ways you can make lifestyle changes to manage or increase your levels of vitamin D.

We’ll take a 3-step approach to help you assess where you’re at, where you want to be, and how you can get there.


The absolute best way to get more vitamin D is to spend more time in the sun. There are a number of factors that impact the amount of sun exposure each individual will need to get adequate vitamin D. 

These factors include:

  • skin pigmentation (a general rule is that darker skin tones require longer sun exposure because darker skin provides more protection to the sun’s rays)
  • age
  • sunscreen use
  • season
  • latitude
  • time of day (2)

Aside from each individual’s natural abilities to convert UV-B rays into vitamin D, the latitude of where you live plays a significant role in whether the sun exposure you can get in various seasons will be adequate enough for your body to produce sufficient amounts of vitamin D. In the U.S., many of the northern states have inadequate sunlight during fall, winter and spring to supply the body with enough vitamin D. 

To get a good idea of how the seasons and the region where you live affects your ability to make enough vitamin D through sun exposure, take a look at the colorful maps used in this article, where you can review a map of proposed vitamin D synthesis in the U.S. for every month throughout the year. (4)

So how much sun exposure is enough? Well, the advice varies as it always does, and with so many different factors at play, everybody is going to have different needs. I’ll offer up what one nutritional scientist suggested in their research word-for-word. 

“Sensible sun exposure (usually 5-10 min of exposure of the arms and legs or the hands, arms, and face, 2 or 3 times per week) and increased dietary and supplemental vitamin D intakes are reasonable approaches to guarantee vitamin D sufficiency.” (2)

Since that’s a fairly simple goal, shoot for that, and then intentionally increase that sun exposure time or the number of days you get out into the sun, particularly if you have a darker skin tone or you live in a northern latitude where sufficient sun exposure is limited in many seasons. Also remember that it’s important to expose bare skin without sun protection on, as your body needs to absorb the UV-B rays that it will then use to produce vitamin D. 

Go get out into the sun for a walk around the neighborhood, tend to your garden, or even wash the dog, with the intention of exposing your skin for some good old vitamin D. Stay conscious of the time or set the timer on your phone, and if you plan to be out in the sun for a longer stretch, bring along the sunblock and apply it after you’ve let some of those rays get in and do their job!


If sun exposure is not good for you for any reason, like you’re on medication that makes your skin sensitive to the sun, you are susceptible to burning, your geographic location is less than optimal, or you’ve been advised to stay out of the sun for any other reason, put the focus on food!

You might be surprised to learn that food sources of vitamin D are actually quite limited and include:

  • fatty fish (like wild-caught salmon, mackerel and tuna)
  • cod liver oil
  • egg yolks
  • liver
  • fermented cheeses, yogurt, and kefir
  • fortified breakfast cereals, milk, and soy products
  • mushrooms

If you are on a keto diet or another restrictive healing diet, try to increase the diet-approved foods that provide some natural vitamin D, like fatty fish and high-quality eggs. If you are vegan or vegetarian, you can DIY vitamin D enriched mushrooms to pack them full of vitamin D. (5

When managing vitamin D levels through diet, you’re going to want to keep track of how much vitamin D you are able to get in each day, and depending on your individual needs based on your age, ability to get sun exposure and skin tone, if you are not getting between 600 to 1,000 IU’s per day, move on to step 3. 


The final step in trying to increase the vitamin D levels in your body is to use a high-quality supplement to make up any shortcomings you have. On days when you have not been able to get adequate sun exposure and your diet did not include foods rich in vitamin D, it’s a great option to take a high-quality supplement. 

There are many supplements on the market, and not all are created equal. When supplementing vitamin D, you first have to know that there are two options, vitamin D2, derived from plants, and vitamin D3, derived from animals. Since vitamin D3, also called cholecalciferol, is the more bioavailable of the two forms, it is an optimal choice for supplementation. But, if you’re leading a plant-based life, there are still good vitamin D2 supplements for you, as well as lichen-derived sources of D3. 

Here are a couple of good supplement options:

If you believe your body is having a difficult time digesting fats, due to gallbladder or liver disease, your vitamin D levels would likely benefit from trying to heal your gut lining and working with a knowledgeable nutrition consultant might be the best way to figure out the right plan for you.

To sum it all up, now is the perfect time to take stock of what your vitamin D intake looks like and take the steps to intentionally increase your levels through a mix of getting out for a breath of fresh air in the bright sunshine, focusing on vitamin D rich foods, and supplementing with a quality supplement on an as-needed basis.


1. Holick M, Chen T, Lu Z, Sauter E. Vitamin D and skin physiology: a D-lightful story. J Bone Miner Res. 2007 Dec;22 Suppl 2:V28-33.

2. Holick M. Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease. Am J Clin Nutr. 2004 Dec;80(6 Suppl):1678S-88S.

3. Parva N, Tadepalli S, Singh P, Qian A, Joshi R, Kandala H, et al. Prevalence of Vitamin D Deficiency and Associated Risk Factors in the US Population (2011-2012). Cureus. 2018 Jun;10(6):e2741.

4. Dr. Joseph Mercola. Vitamin D Resource Page [Internet]. [cited 5th June 2019]. Available from:

5. Kalaras M, Beelman R. Vitamin D2 Enrichment In Fresh Mushrooms Using Pulsed UV Light . Penn State University, Department of Food Science. HAL Project# MU07018. 2009 April 30. 


About author

Heather Cooan

Heather is a marketing executive turned functional nutrition consultant and educator. Heather advocates for informed consent, bodily autonomy, and healthcare authorship. She speaks and writes on nutrition and lifestyle design interventions for health recovery. Heather successfully recovered her health from vulvar cancer, Hashimoto's, and lichen sclerosus. She reversed estrogen dominance, insulin resistance, arteriosclerosis, and fatty liver utilizing a food-as-medicine and integrated clinical treatment approach. Heather is a certified Functional Diagnostic Nutrition® Practitioner, Nutrition Therapy Practitioner, and is earning her Oncology Nutrition Consulting Certification. Heather successfully recovered her health from vulvar cancer, Hashimoto's, and lichen sclerosus. She reversed estrogen dominance, insulin resistance, arteriosclerosis, and fatty liver utilizing a food-as-medicine and integrated clinical treatment approach. Heather is a certified Functional Diagnostic Nutrition® Practitioner and Nutrition Therapy Practitioner.

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