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The Sunshine Vitamin - Vitamin D

by Carly Neubert, BA, NC on November 04, 2020

There is no doubt that these times are trying for many of us. The question is, how does this affect your health? Whether you notice it or not, the stresses of everyday life have the ability to manifest themselves in your body and can influence your health, for the better or for the worse. One crucial vitamin to your body’s functioning is vitamin D. Many of us are vitamin D deficient, and this has a variety of impacts on our bone health and overall immune system.

If you’re curious about the purposes of vitamin D, how to overcome vitamin D deficiency, vitamin D2 vs D3, as well as appropriate dosage levels, this is the source for you.

What does vitamin D do?

Vitamin D is a fat-soluble vitamin that your body naturally makes when exposed to sunlight. Without spending time in the sun, your body won’t make vitamin D.

Without vitamin D you can suffer from all sorts of illnesses including SAD (Seasonal Affective disorder), bone fractures, and immune disorders. Seasonal Affective Disorder (SAD) plagues 5% of the US population. If you suffer from depression and your symptoms intensify during cloudy days or seasons, you are likely a victim of SAD.

Besides regulating mood, some of vitamin D’s important roles are: maintaining bone health and supporting your immune system. It helps your body absorb calcium in the gut, which keeps your phosphorus and calcium levels in check to promote effective bone mineralization. Because of its vital role in bone health, proper vitamin D levels prevent rickets in children and osteomalacia in adults. More recently medical professionals consider vitamin D to be a prohormone, as it also assists in your body’s metabolic functions. Due to its variety of applications, some vitamin D benefits include:

  1. Supports overall immune function
  2. Treatment for familial hypophosphatemia
  3. Treating hypophosphatemia associated with Fanconi syndrome
  4. Increasing calcium levels in people with hypoparathyroidism
  5. Managing low calcium levels (hypocalcemia) and prevents complications in people with Kidney Disease 

These are only a few of vitamin D’s applications in the medical and professional health fields. For more information regarding vitamin D’s health benefits, click here.

How can I increase my vitamin D levels?

An estimated 1 billion people worldwide are vitamin D deficient. In the US, a 2011 showed that at least 41% of adults are deficient in vitamin D. Some integrative practitioners report that 85%-90% of their patients are deficient in vitamin D. Before the landmark study in 2009, doctors and patients were afraid of vitamin D toxicity. In the past, vitamin D supplements usually contained 400 iu (mcg) of vitamin D. Nowadays, vitamin D supplements and prescription medications routinely contain 10,000-25,000 iu (mcg) of vitamin D3.

Because of the strong evidence associating vitamin D levels and proper bodily functioning, supplementation may be beneficial for adults and individuals who are experiencing (or want to prevent) vitamin D deficiency.

There are two main forms of vitamin D: vitamin D2 and vitamin D3. Vitamin D2 (ergocalciferol) is the human-made version of this vitamin. It can be added to foods and is also present in various plants, as well as fungi and yeasts. Vitamin D3 (cholecalciferol), on the other hand, is made in your skin and found in animal-based foods. Vitamin D2 is biologically inactive, meaning that it must be activated within your body to work properly.

Theoretically, your vitamin D levels can be increased through eating foods rich in vitamin D and getting adequate sun exposure. But our modern lifestyle is focused on living indoors. This robs us of important time in natural sunlight. Even when we go outside, most of us are lathered up in sunblock.  

In supplements, both forms of vitamin D are available, however, studies have shown that vitamin D3 is 87% more effective in raising and maintaining vitamin D levels. It only makes sense to take the form that is better and more easily absorbed---vitamin D3 is best used for supplementation and fortification. I only recommend vitamin D3 supplements. Most available multivitamins contain 400 IU (international units) of vitamin D, but high-dose vitamin D supplements are available to consumers as well.

Most of these supplements contain vitamin D3. Here is more information on raising your vitamin D levels and which dose will support your needs.

How is vitamin D absorbed by your body?

When you eat foods with vitamin D or take a supplement it is processed in your body via the aid of bile salts. It is then transported throughout your body by chylomicrons and taken up by your liver or additional storage tissues. Conditions such as celiac disease, cystic fibrosis, biliary obstruction, and chronic pancreatitis often disrupt your body’s absorption of vitamin D, along with patients taking medication that bind bile acids and individuals with obesity. 

Research has shown that vitamin D is most readily absorbed when taken with foods high in fat, thus taking vitamin D with a meal results in a 50% increase in blood levels of vitamin D. Proper vitamin D dosage varies based on the individual’s age, along with reproductive conditions such as pregnancy and lactation.

The recommended vitamin D dose for children up to 1-year-old is 400 IU, for ages 1-70 years 600 IU, and for people over 70 years old 800 IU. Pregnant and lactating women are recommended to take at least 600 IU/d of vitamin D. The table below is from the National Institutes for Health and provides an excellent visual aid for proper vitamin D dosages.

What happens when your vitamin D is low?

Vitamin D deficiency is currently the world’s most prevalent nutritional deficiency, affecting 20% to 80% of people in the United States, Canada, Mexico, Europe, the Middle East, and Asia. The parameters for determining vitamin D deficiency are as follows:

“Vitamin D deficiency is defined as a 25(OH)D level of 20 ng/mL or less, and vitamin D insufficiency as 21 – 29 ng/mL.” 

(Source: https://selfhacked.com/blog/vitamin-d-dosage-sources-deficiency-toxicity/)

This deficiency can be associated with a multitude of health problems, including cardiovascular disease, autoimmune disorders, and even cancer. Some of its symptoms include: fatigue, back/bone pain, weakness and aches, digestive issues, obesity, mood swings, and decreased immunity.

Likewise, many other factors can contribute to the emergence of vitamin D deficiency, such as low exposure to sunlight, gut disorders, liver/kidney disease, strict vegan diets, and certain medications. If you fall under any of these categories or often experience any of the symptoms mentioned in the paragraph above, you may be suffering from inadequate vitamin D.

Are there any foods that provide vitamin D?

As I mentioned earlier, some foods do contain vitamin D. Though it is possible to absorb vitamin D through these foods, they are rather few and far between. The best natural sources are fatty fish like salmon, tuna, and mackerel, along with fish liver oils. Vitamin D in these sources is most prevalent in the form of vitamin D3 (body ready form).

In addition to these natural sources, fortified foods make up the majority of vitamin D in the average American diet. Dairy products such as milk and yogurt, plant-based milk alternatives, and some breakfast cereals are often fortified with vitamin D as a result of a milk fortification program that was implemented in the U.S. in the 1930s.

While this may sound like a great system, most of the fortification is D2 (the inert form of vitamin D). Additionally, fortified foods usually have preservatives and sugar, not to mention loads of carbohydrates. Fortified food is not your best option for raising or maintaining healthy vitamin D levels. 

Below is a table from the National Institutes of Health, representing some of the most common food sources for vitamin D, as well as their associated vitamin D levels.

You have gained some insight into the valuable role that vitamin D plays in the daily function of the human body, as well as in the prevention of damaging, and even deadly, diseases. For a majority of the population, vitamin D supplements are necessary for optimal health and vitality.

If you would like a customized plan to increase your daily intake of what some have lovingly titled “the sunshine vitamin” schedule a consult with me, Carly Neubert, BA, NC.


Carly Neubert BA, NC


For additional recipes, biohacking tips and lifestyle hacks -- check out my other blog on my coaching site www.cleancoachcarly.com! I post weekly about nutrition and lifestyle topics, all backed by science. Happy Reading!


  1. https://pubmed.ncbi.nlm.nih.gov/20200983/
  2. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/
  3. https://selfhacked.com/blog/vitamin-d-dosage-sources-deficiency-toxicity/
  4. https://www.healthyhabitsliving.com/blogs/be-healthy/sad-reality-of-vitamin-d-deficiency
  5. https://www.uchicagomedicine.org/forefront/coronavirus-disease-covid-19/vitamin-d-deficiency-may-raise-risk-of-getting-covid19
  6. https://selfhacked.com/blog/35proven-health-benefits-vitamin-d-part-1/
  7. https://www.ncbi.nlm.nih.gov/books/NBK208880/