The Sunshine Vitamin

The sunshine vitamin is an appropriate nickname for this unique nutrient, as it is the vitamin that comes from the sun. In fact, it is the only essential vitamin that we can get from a non-food source. There is no other nutrient that binds us so intimately with our environment, so there is much to marvel about the sunshine vitamin. 

In this post, we will explore the sunshine vitamin, revealing its mysterious shape-shifting properties, why we need it, and how you can get it. 

First, let’s get to know the sunshine vitamin by its given name. 

What is The Sunshine Vitamin?

The sunshine vitamin is the vitamin that we get from sunlight exposure, otherwise known as Vitamin D. 

We will share with you some of the amazing health benefits of vitamin D in a minute. First, lets take a closer look at why Vitamin D owns-up to its nickname of the sunshine vitamin.

Let There Be Sunlight

Sunlight is the ultimate reminder of the cyclic nature of life, of the divine providence that created and maintains all life on Earth. “Let there be light!” And all it encompasses. 

In our hurried modern lives, most of us take sunlight for granted: the sun always rises. But for a long time past, the sun was worshipped as a god for its life-giving power.

Sunlight Vitamin D

Humans have long associated the sun with survival at the most basic level. But also as an important symbol of vitality, the bounty of nature, and the delicate balance between sunlight and survival. 

In modernity, however, we have lost some of those intimate connections between sunshine and our livelihoods. Luckily, we are not without ample reminders, if we take the time to appreciate them. 

The life-giving energy we get from the sun is reflected all around us. But there is also a quiet, constant, and deep connection we have with the sun that is less obvious. 

Sunlight is essential to our natural ability to create Vitamin D. The human body has adapted the ability to capture a narrow spectrum of the sun’s vast array of energy in our skin and turn it into vitamin D. 

From the rays gifted to us by the sun, we can make more vitamin D than we will ever need. 

Where Does Vitamin D Come From?

Energy from the sun gives life to all living things one way or the other. We consume the sun’s energy through all of our food. But we are not exempt from needing some direct sunshine ourselves. 

To say that the sunshine vitamin – vitamin D, comes from the sun is only telling part of the story. Vitamin D that exists in nature – beyond the confines of our own skin, results from plants and other animals converting sunlight into energy. 

Grasses on land and plankton in the sea produce vitamin D as part of the energy cycle that sustains them. When other animals feed on grass, hay, plankton, shrimp, etc. the vitamin D builds-up in the fatty tissues of those animals. We will get to how that works later. 

benefits of sunlight


So the vitamin D we need might come from eating those animals that have large stores of vitamin D. This is what is called dietary vitamin D. But the sunshine vitamin got its name from the other origin of vitamin D: our own ability to turn sunlight into vitamin D. 

Let’s take a closer look at how this amazing nutrient works.

What is Vitamin D?

Vitamin D is an essential vitamin, which means we need to get it from our environment in order to survive. It is also a fat-soluble vitamin, which means it can dissolve and be stored in fats. This is why most of our dietary intake of vitamin D comes from eating certain animals that are high in fat.

These two qualities are part of what make vitamin D so unique. But also why it can be difficult for us to get enough vitamin D.

We absorb vitamin D along with animal fats we consume in our diet. So we can get some vitamin D from our diet and can even store the extra vitamin D in our own fat deposits and in our liver. 

fish vitamin d

The problem is that vitamin D is found in very few foods (see our list below.) So unless you eat a diet heavy in fatty fish, you are likely not getting enough vitamin D through your diet alone.

 Luckily we have adapted to create our own Vitamin D supply. Provided we get enough sunshine. Thus, “the sunshine vitamin.” 

In fact, because our bodies can produce vitamin D, it is technically classified as a prohormone, specifically a secosteriod – or a subclass of steroid noted for their “broken” chemical structures. So you may sometimes see vitamin D referred to as a hormone.

But Vitamin D is also a vitamin, which means we can get some – or (arguably) all, of our needs through our diet. For most people, the dual approach of sun-produced vitamin D and dietary vitamin D is the best option. We will get into that later on. 

Next, let’s look at why the sunshine vitamin is so important to our health.

The Health Benefits of Vitamin D

The health benefits of vitamin D are numerous. Researchers are continuing to discover more ways in which vitamin D is involved in essential functions. Vitamin D is known to play a role in both preserving and promoting good health in areas such as: growth, cognitive function, immune health, healing, aging, bone health, anti-cancer, cardiovascular health, and even mood. 

Our Incomplete List of The Health Benefits of Vitamin D

Because the consensus among healthcare professionals is that most people do not get enough vitamin D (see below), the health benefits of vitamin D are really best viewed from the perspective of preventing or alleviating a deficiency. 

Why Do We Need Vitamin D?

Vitamin D is one of 13 essential vitamins; we cannot survive without it. 

We need enough vitamin D to maintain overall health, but adequate levels of vitamin D is also associated with the prevention of many diseases such as cancer, heart disease, stroke, diabetes, and autoimmune disorders. In order to appreciate the importance of vitamin D, let’s look into what it does for our health.

What Does Vitamin D Do?

Without enough vitamin D, our bodies can’t properly absorb calcium because Vitamin D helps promote calcium absorption in the gut. 

Vitamin D reduces risk of Osteoporosis

Vitamin D- Reduced Risk of Osteoporosis

Vitamin D also helps maintains healthy levels of calcium and phosphate in the bloodstream, which promotes normal mineralization of bone. Calcium is also an important part of neuromuscular activity, so low blood calcium levels can result in serious complications.

Vitamin D is necessary for bone growth and healing. If vitamin D levels are too low, bones fail to hold their shape and structure and can become brittle or even misshapen. 

Vitamin D also has many other roles in the body, including: cell growth, immune functioning, anti-inflammation responses, and neuromuscular activity. 

Vitamin D Deficiency

A vitamin D deficiency is one of the most common nutrient deficiencies. 

In children, a vitamin D deficiency causes rickets. In older adults it can cause osteoporosis, a serious condition in which bones can no longer keep up the replacement of dying bone tissue and the bones become weak and brittle. 

Research consistently shows that we are not getting enough vitamin D, be it from sunshine or from food. 

For example, the Center for Disease Control (CDC) in their National Health and Nutritional Survey found that only 23% of Americans tested had the recommended blood serum level of vitamin D. In the previous survey, just 10 years prior, 45% of those tested had adequate levels of vitamin D. 

Though some in the research field have challenge the methodology of this kind of research, the trend of decreasing vitamin D levels may indicate that the American diet and modern lifestyle are increasingly working against our ability to get enough vitamin D.

Note: there are ongoing debates as to the amount of vitamin D we need, how it is measured, and what constitutes a “deficiency.” The National Institute of Health, for example, maintains a much lower threshold than the CDC. 

In terms of dietary vitamin D intake levels, the various research bodies are much more in agreement: most Americans are not consuming enough dietary vitamin D. 

A 2014 survey by the CDC indicated that 81% of children (2 to 8 years) were not consuming enough vitamin D. By adulthood that number jumps to 95%! 

Our ability to manufacture vitamin D out of sunlight exposure – and how this process happens, is really what makes this nutrient so special. Let’s dig in.

How Do We Make Vitamin D from Sunlight?

In order to produce vitamin D, your skin must be exposed to the sun. Much like plants can convert sunlight into energy from carbon dioxide and water (photosynthesis), we produce vitamin D through a photochemical reaction in our bodies. Here is how it works.

photosynthesis vitamin d

Plants use their leaves for photosynthesis

Cells in your skin layers contain a type of cholesterol, called 7-dehydrocholesterol or provitamin D3, which is reactive to sunlight. The ultraviolet-B (or UVB) rays in sunlight cause the provitamin D3 to convert to previtamin D3, which in turn spontaneously converts into the prohormone calcitrol. 

This process is called photolysis and it all takes place in the outer layers of your skin called the epidermis.

Vitamin D we produce from sunlight – as well as what we consume in food and supplements, all must undergo further processing in order to become active, also known as bioavailability. This means the hormone-type structure of vitamin D needs to be converted into a form that your body can use directly.

So once the prohormone of vitamin D is produced in the skin, it binds with special proteins in the fluid surrounding your skin cells. This protein then carries it to the liver and kidneys where it is converted into two different active forms and distributed throughout the body.

Similarly, when vitamin D3 is taken as a supplement, it is absorbed in your intestine. From there, it is collected by the same binding protein that’s in your skin and taken to the liver where it is converted to its bioactive form.

How Much Vitamin D Do I Need?

The question of how much vitamin D is enough is tricky. There is no clear and simple answer. There are, however, guidelines that give you an idea of what you might need in terms of dietary intake.

But there is also ongoing debate among researchers and medical practitioners in a variety of fields as to how much is enough. 

While the recommended amounts can vary wildly (many think the guidelines are way too low), the general consensus is that most people are not getting enough vitamin D, regardless of where each health agency may draw the line. 

We will get to why we aren’t getting enough vitamin D in a minute. First, lets look at some official recommendations for vitamin D intake. According to the National Institute of Health (USA) and the Food & Nutrition Board, these are target amounts of vitamin D, by age.

Life StageRecommended Amount
Birth to 12 months400 IU
Children 1-13 years600 IU
Teens 14-18 years600 IU
Adults 19-70 years600 IU
Adults 71 years and older800 IU
Pregnant and breastfeeding women600 IU

These guidelines are generally for those who are looking to take a vitamin D supplement in addition to their dietary vitamin D intake. But this post is about the sunshine vitamin, so let’s look at why getting sunshine is the best way to make sure you are getting enough vitamin D.

Vitamin Supplement vs The Sunshine Vitamin

Our bodies are designed to produce vitamin D from sunlight in the form of vitamin D3. Vitamin D3 from sunshine is the most natural way to get the vitamin D you need. Here is why.

vitamin d supplements

Vitamin d supplements

While supplements can be a fine way to make sure you are getting a base level of nutrients, including vitamin D, they can never replace the nutrients you get from natural sources like whole fruits and vegetables and grass-fed meats. 

In the case of vitamin D, the type of vitamin D your body produces from sunlight is the best, most biologically active form. With that in mind, let’s look at the two types of Vitamin D.

Vitamin D2 vs Vitamin D3

There are two types of vitamin D supplements widely available. Vitamin D2, or ergocalciferol, which is the type found in most multivitamins, supplements, and food additives; and vitamin D3, or cholecalciferol, the natural form found in animals.

Vitamin D2 is synthesized from yeast or other plant matter. Unfortunately, the body does not utilize the D2 form so your body has to convert it into D3. There is a lot of debate as to the efficiency of this conversion. 

Your body can convert some D2 into D3, but many researchers believe this process is limited and so the dosage-to-absorption ratio may be quite low. 

Further, some researchers believe that D2 may even interfere with the natural production of D3, which is counterproductive to maintaining healthy overall vitamin D levels.

Because of the synthetic form and additional processing required of D2 it is not the best supplement form. But it is less expensive and more widely available than its counterpart, D3.

Vitamin D3, or cholecalciferol, is the naturally occurring form found in animals. It is derived from either fish oils, such as salmon or sardine, or from sheep lanolin – a substance produced by glands in sheep’s skin. 

Because D3 is the form readily utilized by the body, much more of it will be absorbed, and you will receive more of the vitamin D benefits. 

Both supplement types have the disadvantage of being processed. This means there are likely some binding agents or carrier other oils that can go rancid. Plus, you have to remember to take them!

The health benefits of vitamin D are largely based on the benefits of getting natural, free, and easy vitamin D from sunlight. Let’s look at why this is true.

The Sunshine Vitamin: The Best Source of Vitamin D

Naturally produced vitamin D from sun exposure is the best, most readily available form of vitamin D. Dietary vitamin D is good too – and you get the other benefits of the healthy fats found in fish. But fatty fish is not a typical American meal. And we are clearly not getting the dietary vitamin D we need. 

Herring vitamin d

Herring is high in vitamin D

For the cost conscious: vitamin D from sunlight is FREE. Plus, you body can produce almost unlimited amounts of this form of vitamin D without any toxicity concerns as with many vitamin D supplements. 

Your body knows how much vitamin D it needs. So when you produce more of the sunshine vitamin than you need, it simply stores the extra. And finally, with the sunshine vitamin there is no possibility of toxic build-up as there is with vitamin D2.

Why Aren’t We Getting Enough Vitamin D?

The challenge of getting enough vitamin D is threefold. 

First, it is difficult to measure how much we are getting from food and sunlight.

Second, because vitamin D is found only in a few types of foods (primarily fatty fish) – and our modern diet is consistently lacking in those foods, most people are just not able to consume enough through diet alone. 

And finally, we are just not getting sunshine like we used to get.

Have we always struggled to get enough vitamin D? Perhaps. But there are definitely some environmental and behavioral changes over the last 50 years that are worth noting. In short, our relationship with the sun has changed quite a bit. Lets look at how and why.

We Don’t Spend Time Outside

Over the past several decades, the amount of time people spend outside has been declining. A 2001 study by the Environmental Protection Agency (EPA) found that the American adults surveyed spent 93% of their time indoors and only 7% of their days outside. 

More people work in offices and spend time commuting by car than ever before. Our increasingly indoor-centric and sedentary lifestyle means less time to get the sun exposure we need. Greater urbanization has also likely played a role in keeping people inside.

Children are also spending less time outside. The decline in unstructured play and less recess and physical education time during school hours has cut into the amount of time that kids spend outside. A higher level of engagement with screen-based technologies also means kids are spending less time outside. 

See our post on What is a Digital Detox? about how you and your kids can reduce screen time.

A British study recently found that the children surveyed spent around 4 hours per week outside – less than half the amount their parents did at the same age. And far less than the two hours per day that is guaranteed to those in prison!

We Don’t Eat Fish

Foods that contain high levels of vitamin D, like fatty fish, are not a regular part of the modern American diet. The shift from fresh foods to prepared and processed foods has also squeezed out a lot of the foods naturally higher in vitamin D.  

maties vitamin d3



Recent research on heavy metals and other toxins has also likely helped gradually reduce fish consumption since 1997. Even though Americans still consume around 16 pounds of fish products per year, this is not much when compared to the 175 pounds of flour and cereal products.

Long Sleeves & Sunscreen

Call it the cancer paradox. We have become much more aware of the potential damaging affects the sun can have on our skin. As a result, the preventative measures like sunscreen, hats, long-sleeves, and generally just staying out of the sun has changed a lot about how we behave. 

Skin cancer is a serious threat to our health. So it makes sense to take precautions. There is no doubt that radiation from the sun is associated with skin cancer – and other less critical, but still serious damage. 

But the near obsession with preventing sun exposure just might be limiting our ability to produce the vitamin D we need. The paradox of sun damage versus sun exposure for vitamin D can be particularly tricky to manage in the case of children.

sunlight and vitamin d3

Luckily, the sunshine vitamin is not a greedy partner. You do not need to lie the sun all day to get a healthy dose of vitamin D. There is a sweet spot. Hopefully we will help you find yours. And as Hildegard would advise: it’s about moderation. 

What is the Right Amount of Sun for Health?

There is no “one size fits all” when it comes to sun exposure. Just as there is no simple answer to “is the sun good for you?” 

Many different factors, both individual and environmental, determine how much sunshine is healthy. You need to find a solution that works for you. Hopefully these tips on how much sun you need to get vitamin D can help. 

A Little Sun Goes a Long Way

Whether you are already frolicking in the summer sun or waiting in your winter sweater for the sun to come out, getting a daily dose of sun is a great way to stay healthy year-round. 

You don’t need to completely redesign your daily routine to enjoy the health benefits of vitamin D. Most of the vitamin D benefits from sunshine exposure come as a result of very little sun exposure.

Remember, you should never expose your skin to sunlight until you become sunburned. A general rule when it comes to capturing the vitamin from the sun is to expose your skin for about half as long as it takes for your skin to begin to turn slightly pink. 

Sun exposure on your arms and lower legs for 10-15 minutes in the middle of the day, two or three times per week should be enough for the average person to produce the vitamin D they need.

When in doubt, just remember that a little sun goes a long way in getting the health benefits of vitamin D. Moderation in duration and frequency of exposure are key.

sun and vitamin d

Here are some factors that will also help you determine how much sun exposure is healthy for you.

  • Time of Day
  • Your Age
  • Your Skin Color/Tone
  • Skin Exposure
  • Geography/Latitude
  • Elevation
  • Season/Time of Year

Time of Day

The optimal window for sunlight exposure for vitamin D benefits is between 11AM and 3PM. If you are in this window, you will need the least amount of time exposed. 

Your Age

The older we get, the less efficient our bodies are at making vitamin D from sunshine. By the time you are 65 or older, your body produces only about 25% of the vitamin D as when you were in your 20’s with the same amount of sun exposure. So generally, the older you are the longer you may need to stay exposed. 

Skin Color/Tone

People with naturally darker skin are less efficient at converting sunlight into vitamin D. This is for roughly the same reason they are less likely to burn. The amount of melanin in skin affects how much of the ultraviolet radiation enters your skin. The darker your skin, the longer you will need to be exposed.

Skin Exposure

The more skin you have exposed, the shorter you need to be exposed. It is a simple matter of surface area. The average skin exposure times assumes both arms and lower legs being exposed. So anything less than that will require more time in the sun.


The further from the equator you live, the longer you will need to be exposed. The sun’s rays are most direct at the equator and diffuse as they extend north and south. 


Elevation is something to consider if you live somewhere like Denver or Mexico City. Generally, the higher the elevation the more exposed you are to the sun’s rays. So if you live at high elevation you will need less time in the sun than when at sea level.

Season/Time of Year

Much like geography/latitude, the further from the equator you are the less likely that you will get ANY vitamin D from sunshine in the winter months. 

In fact, if you live north of 37 degrees latitude (roughly 2/3 of the USA) you will not be able to get vitamin D from sun exposure from around October or November through March. This is because the sunlight is at too low of an angle to provide the UV radiation necessary for vitamin D production.

Foods High in Vitamin D

The sunshine vitamin can’t do it on its own. You still need to eat foods high in vitamin D. So if it’s the middle of winter, or you just can’t find the sun, you can add these foods to our list of winter foods to stay healthy all winter.

fish source vitamin d

Most foods high in Vitamin D are varieties of fatty fish. In fact, the only natural vegetable source of vitamin D is mushrooms. Here are some foods high in vitamin D and their approximate vitamin D content, per 100g (3.5 ounces):

  • Salmon (150-1,000 IU)
  • Halibut (400-700 IU)
  • Sardines (250-350 IU)
  • Mackerel (300-500 IU)
  • Herring (1,200 – 1,600 IU)
  • Oysters (300-400 IU)
  • Egg Yolks (100-1,000)*
  • Mushrooms (1,200-2,000 IU)**

*Some egg producers offer eggs produced by chickens fed a diet high in vitamin D, resulting in some vitamin-D enriched eggs up to 2,000 IU

**Only natural plant source of vitamin D

Sources: USDA 

Many processed or cultivated foods are also enriched during production to include supplemental vitamin D. Foods high in added Vitamin D2, include:

  • Milk (Dairy, Soy & Nut)
  • Cereal & Processed Grains
  • Orange Juice

Final Thoughts on The Sunshine Vitamin

Let’s review a couple of things to keep in mind when getting your sunshine vitamin.

Many factors affect the skin’s ability to produce vitamin D. It is important to know where you fit relative to the factors that influence how much time in the sun you need. 

Most dermatologists recommend avoiding the sun altogether and using sunscreen on skin when exposed to the sun. They recommend getting vitamin D from food and supplements rather than taking any risk of potential sun damage. 

Other health professionals believe that vitamin D is so important – and most people are not getting enough, that a moderate amount of sun is worth it.

There are other factors like being pregnant, overweight, or chronic illness that may also affect your vitamin D needs. 

It is always best to discuss your particular health situation with your medical practitioner before taking any supplements or making significant lifestyle changes.

Happy Sunshine!


Additional Sources:

  • Journal of Exposure Analysis and Environmental Epidemiology volume11:231–252 (2001) National Human Activity Pattern Survey (2001/2011)
  • National Institute of Health, Office of Dietary Supplements
  • Harvard University, Harvard Medical School “Benefits of Moderate Sun Exposure”; “Time for More Vitamin D”
  • Gangwar AK, et al. Role of vitamin-D in the prevention and treatment of Alzheimer’s disease. Indian Journal of Physiology and Pharmacology. 2015;59:94.
  • Yin Y, et al. Nutrient biomarkers and vascular risk factors in subtypes of mild cognitive impairment: A cross-sectional study. 2015;19:39.
  • Wood JM, et al. Vitamin D and neurocognitive disorder due to Alzheimer’s disease: A review of the literature. Annals of Clinical Psychiatry. 2015;27:206.
  • American Academy of Dermatology
  • American Cancer Association
  • “Sunshine is good medicine. The health benefits of ultraviolet-B induced vitamin D production.” Journal of Cosmetic Dermatology, 2003 Apr;2(2):86-98. 

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