| LINDSEY WILSON

Vitamin D - One Nutrient, Many Jobs

All vitamins are crucial to having properly functioning organs. We all know that vitamin C helps your immune system, vitamin E assists with cell repair, and vitamin A is for eye health. There’s a whole catalogue of B vitamins that help with everything from brain functions to energy production.

Each vitamin contributes to multiple causes within your body’s  network of systems. But there’s one vitamin that seems to do it all. Vitamin D.

What’s So Special About Vitamin D?

Why are so many kids' cereals fortified with vitamin D? We’ve all heard of orange juices targeted toward children with vitamin D mentioned in the brand name. Even kid’s yogurt packets advertise their product with vitamin D fortification. The push to get kids to consume more of this nutrient is due to the shocking statistic that nearly half (41.6%) of the U.S. population is deficient in vitamin D

This condition is linked to many health issues that can really mess up your quality of life. In western diets, whole foods are less present and are being replaced with processed foods. On top of that, there are many factors keeping everyone indoors more often than out. Because of this, getting enough sun exposure and dietary vitamin D has never been more important.

The Sunshine Vitamin

When your skin is exposed to the sun, it produces Vitamin D. This is a natural occurrence if you’re exposed to UVB rays frequently enough. But the amount of D produced by sun exposure isn’t enough to satisfy your bodily functions. Your best bet is consuming it through your diet.

Vitamin D is a fat-soluble vitamin. That means it dissolves in oil and fat and your body stores it for a long time. This function is one of the many superb ways that your body looks out for you. If you are unable to get your hands on this vitamin for a few days, you’ll have plenty stored in the bank so that your bodily functions can still carry on. 

That being said, you should still aim to ingest the daily recommended amount of vitamin D so that you can go through life feeling great, day in and day out. 
The two main dietary forms of vitamin D are D2 and D3. Vitamin D2 is  found in a few plants, mushrooms, and yeasts. Vitamin D3 is found in some animal foods such as fish and eggs (the yolks, specifically). D3 is more likely to raise your vitamin D blood levels than D2, so it’s good to include both sources in your diet.

What Does Vitamin D Do Inside Your Body?

Let’s get scientific for a moment to discover what happens to vitamin D while it travels throughout your body.

The first stop: your liver. Here the vitamin is converted to calcidiol so that your body can store it. Think of this as putting away your groceries until you’re ready to pull them out and use them.

The next stop: your kidneys. This is where the vitamin is activated and converted into calcitriol. This is where you pull out your groceries and start preparing or cooking with them. Calcitriol is the steroid-hormone version of vitamin D - the same version that's produced when your skin is exposed to the sun.

Now that the vitamin D is active in your body, and can bond with the Vitamin D Receptor (VDR) which exists in every single one of your cells. That means your cells can start absorbing minerals like calcium and phosphorus from your gut, and you’re on your way to fortified bones!

Signs of Vitamin D Deficiency

The biggest impact of low vitamin D stores is compromised bone composition. This is when your body isn’t getting the amount of vitamin D that it needs to absorb an appropriate amount of calcium. On average, you can only absorb about 10-15% of the calcium you need compared to 30-40% with proper stores of vitamin D

But it’s not only about your bones. Scientists are accumulating more and more evidence that many of your body’s tissues contain vitamin D receptors: your heart, blood vessels, prostate, endocrine glands, and muscular tissue. That means that vitamin D contributes to multiple aspects of your overall health. 

Your body might be vitamin D deficient if you’re diagnosed with one or more of the following health conditions.

  • Rickets - bone disease more common in children in developing countries 
  • Osteomalacia - soft bones 
  • Osteoporosis - can lead to spinal deformities 
  • Fractures in older adults - caused by the body pulling calcium from the bones to support other bodily functions 
  • Heart disease - Heart attack survivors are more at risk because of an association between post-heart attack deficiencies
  • Diabetes - vitamin D helps with glucose metabolization
  • Dementia - low vitamin D is linked to mental health issues
  • Autoimmune diseases - for example, Multiple sclerosis 

Immunity Booster

Vitamin D is also responsible for directly interacting with cells that fight infections. Studies show a link between low vitamin D levels and respiratory tract infections including the cold, pneumonia, and bronchitis. Keeping a good balance of vitamin D circulating through your body means a healthier life with fewer illnesses.

Fatigue Fighter

American culture often champions those of us who work until we drop. Fortunately, we’re seeing a shift in that mindset and are now setting boundaries for ourselves and learning to say ‘no’ more often. But maybe you’ve evolved your work-life balance by building in good rest periods and getting your eight hours of sleep, and you’re still exhausted throughout the day. Vitamin D might be the culprit. 


Many studies demonstrate that low vitamin D blood levels can cause fatigue severe enough to have a negative impact on your life in a significant way. 

Helps With Depression

Research is limited in this arena, but the fact still remains: mental health disorders are associated with vitamin D deficiencies. The research that does exist points to the connection between vitamin D and multiple neurological functions including the production of dopamine. 

One study showed an improvement in depressive symptoms in patients who increased their vitamin D levels with supplements. Another resulted in a wide sampling of adults being less inclined to depressive symptoms and traits if their vitamin D blood levels read high.

The Best Food Sources for Vitamin D

According to the National Institutes of Health, the following are the foods most rich in vitamin D with their percentages of the daily recommended intake included. 

  • 1 tablespoon of cod liver oil - 170%
  • 3 oz of cooked trout - 81%
  • 3 oz of cooked salmon - 71%
  • ½ cup of raw white mushrooms - 46%
  • 1 large whole egg - 6%
  • 3 oz of tuna in water - 5%
  • 1 sardine, canned in oil - 4%

Other foods include:

  • Beef liver
  • Portabella mushrooms
  • Fortified milks - including oat, almond, and soy
  • Fortified orange juice
  • Fortified yogurt

Fortify Your Body

With whole foods boasting dense nutrient profiles. Organic fruits and vegetables and grass-fed and finished animals are the best way to be sure you’re consuming plenty of vitamins and minerals. When you do everything you can assist your body in functioning properly, you get to experience life at a high quality. Eat well, live well.