What if I told you that the majority of the population is suffering from sunshine deficiency — otherwise known as vitamin D deficiency? Due to cold climates, gloomy days, pollution, and our indoor lifestyle, low vitamin D levels are rampant. No wonder it is one of the most commonly recommended supplements on the market.

What are the benefits of vitamin D? Can you be deficient if you are living in a sunny area? Should you take vitamin D supplements? These are just some of the questions I will answer in this article. Let’s get started.


Sunshine over flower field

What Is Vitamin D?

Did you know that it is not just a vitamin? It is actually a prohormone (1). Prohormones are substances that your body converts into hormones. Hormones serve as your body’s chemical messengers. They move through your bloodstream to various organs and tissues to support important processes, including growth and development, immune function, sexual function, reproduction, metabolism, and mood. As a prohormone, it supports these vital functions.

Vitamin D is fat-soluble, which means that it is absorbed with the help of fats and is stored in the liver and fatty tissues. It is also the only vitamin that your body is able to manufacture. When your body is exposed to the UV rays of the sun, it can create Vitamin D . With ALL your other vitamin needs, they must be obtained through diet and supplementation.

Sunshine is the best and main source of vitamin D. It’s no wonder it’s often called the ‘sunshine vitamin’. Besides sunshine, there are a few foods that contain vitamin D (more on that later!) and if you are like many of my patients, you may meet your needs through supplementation too, even if you live in sunny climates.


Sunshine over field

Low Vitamin D or Sunshine Deficiency?

Since sunshine is the primary source of VIT D production, you may not be surprised to hear that a lack of sun exposure can lead to deficiencies. Back in the day, our ancestors lived a mainly outdoor lifestyle in a non-polluted natural environment. Vitamin D deficiency was probably not common then. This is not the case today. Low vitamin D is one of the most common vitamin deficiencies (2, 3).

Many people live in places where sunshine is limited. If you live in California, Florida, or other states, you may be able to play outdoors in the sun year around. This is not the case everywhere. Cloudy, rainy, snowy, and gloomy weather leads to limited sun exposure. Not to mention, if it’s cold outside, you may be less likely to spend as much time outdoors. Even though Colorado is one of the sunniest states, due to the long winters and cold temperatures, you may be bundled up, not getting enough sun exposure.

Living in sunny and warm places doesn’t ensure adequate VIT D levels either. If you are hiding inside enjoying the air conditioning, you are missing out on the benefits of the sunshine. Living an indoor lifestyle, working from indoor offices, going to school indoors, and even socializing inside seriously limit your sunshine vitamin intake, regardless of the climate.

Living in a big city where tall buildings block the sun or living in an area with high outdoor pollution can also limit sun exposure. So does sunscreen.

To protect you from developing skin cancer and burning your skin, doctors tend to recommend using sunscreen all year around. While this may help to protect you from UV rays, sunblock may also decrease your body’s ability to make VIT D by up to 90% (4). Using SPF 30 sunscreen or higher may reduce your body’s ability to make vitamin D by 99%.

Yep, if you are using sunscreen, you may be missing out on the benefits of the sun. But then you are reducing your risk of sunburn, skin damage, and skin cancer. It’s a catch-22.

Other factors

Other factors that may increase your risk of low VIT D levels include (2):

  • Dark skin: People with darker skin have higher amounts of the pigment melanin in their skin, which may decrease their skin’s ability to create vitamin D from sunlight.
  • Age: The skin’s ability to synthesize Vit D decreases as you age, putting older adults at higher risk of vitamin D deficiency.
  • Health conditions that limit fat absorption: Since itis a fat-soluble vitamin, health conditions, including cystic fibrosis, liver disease, ulcerative colitis, Crohn’s disease, and celiac disease, may reduce the body’s ability to absorb VIT D and increase the risk of deficiencies. People with certain conditions may not be able to eat foods rich in vitamin D or may have difficulty absorbing it from vitamins.
  • Obesity: Obese individuals will need a much greater amount of vitamin D to meet their requirements. The usual recommendations tend to fall short in providing adequate vitamin D, increasing the risk of low vitamin D levels in obese individuals. Gastric bypass surgery may also complicate the situation. In this procedure, a part of the upper small intestine is bypassed. Since this is where vitamin D gets absorbed, those that receive a gastric bypass surgery are at an increased risk of vitamin D deficiency and need regular monitoring.
  • Breastfed infants: Though breast milk is the best food for babies, human breast milk is not the best source of vitamin D. Though sun exposure can certainly help, the American Academy of Pediatrics (AAP) doesn’t recommend that children under 6 months are exposed to direct sunlight. To improve levels, vitamin D supplementation is recommended in both breastfeeding mothers and babies.
  • Genetic mutations: Some vitamin D-related genes such as Vitamin D receptor (VDR) genes and others can impact vitamin D levels and increase risks of diseases associated with low vitamin D levels such as autoimmune conditions, cancer, and atopic diseases, like allergies, eczema and asthma.  Exactly HOW these gene mutations or variants impact vitamin D levels is still being researched (5, 6, 7, 8, 9).


Woman with vitamin D deficiency

Symptoms of Vitamin D Deficiency

Signs and symptoms of low levels may include:

  • Fatigue
  • Bone fragility and osteoporosis
  • Muscle weakness
  • Muscle twitching
  • Muscle pain
  • Joint stiffness
  • Poor sleep or insomnia
  • Trouble concentrating
  • Poor memory
  • Brain fog
  • Immune system problems
  • Depression, anxiety, and mood disturbances
  • Skin inflammation and skin health issues

Prolonged deficiency may increase the risk of:

  • Osteoporosis
  • Cardiovascular conditions
  • Autoimmune issues
  • Chronic pain, including fibromyalgia
  • Neurological conditions
  • Mental health issues, including depression and anxiety
  • Increased infections and slow recovery
  • Pregnancy complications
  • Cancer
  • Diabetes
  • Atopic disease: allergies, eczema, asthma


Pregnant woman doing yoga at lake during sunset.

Benefits of Vitamin D

There are just so many health benefits of Vitamin D!  It is truly amazing how many aspects of our health and our lives are impacted by this little molecule!   Let’s take a look at some of them!

Improved Immune Function

One of the most important is the role it plays in immune balance (10). Now the immune system is MUCH more complicated that we can cover in this blog, but it is divided into 2 main segments, the innate (what we are born with) and adaptive (what we develop over time) immune responses. It plays a role in both segments. And research shows that low vitamin D levels may increase your susceptibility to chronic infections. It may slow your recovery from illness, including the flu and COVID-19 (11, 12). This deficiency may also increase your risk of autoimmune conditions, including type 1 diabetes, rheumatoid arthritis (RA), multiple sclerosis (MS), inflammatory bowel diseases (IBDs), and lupus (13, 14). Low vitamin D levels may also increase the risk of allergies, eczema and asthma (15, 16, 17).

Enhanced Bone and Joint Health

Your bones and spine provide structure, support, and a framework for your body, just  like steel beams provide structure and support for a building Joints serve as hinges, akin to doors and windows, allowing certain parts to move safely! It works in synergy with vitamin K promoting bone and joint health and reducing the risk of weakness, fractures, and pain. Furthermore, it helps to reduce the risk of osteoporosis, osteopenia, osteoarthritis, cartilage loss, joint inflammation, and joint pain (18, 19).

Better Heart Health

As you may know, heart disease is the number one leading cause of death in the United States (20). Vitamin D deficiency may increase your risk of conditions related to the cardiovascular system, including high blood pressure, heart disease, heart failure, and stroke (18, 21). The good news is that optimizing your VIT D levels may help to reduce your risk of hypertension and cardiovascular disease.  And it is an easy fix!

Improved Cognitive Health

One of your most important organs, your brain, is like a computer processor, the central component of a computer. Your brain is the central unit of your body that processes information, executes key commands, and controls important functions. Neurodegenerative conditions, such as dementia and Alzheimer’s disease, can affect brain function, thinking, comprehension, language, memory, and behavior. It affects your ability to perform everyday tasks. Research suggests that vitamin D deficiency may increase the risk of dementia and Alzheimer’s disease and that vitamin D supplementation may lower the risk of cognitive decline (22).

Better Mental Health

Considering that vitamin D is so important for brain health, you may not be surprised to learn that it’s also critical for your mood and mental health. It may play a particularly important role in reducing the risk and improving anxiety and depression, two increasingly common mental health issues (23, 24). It is especially important during the darker winter months. Seasonal Affective Disorder (SAD) may not only be the result of darkness but also reduced vitamin D production. It can support serotonin synthesis, which also helps to boost your mood and depression (25).

Improved Sleep

It is also essential for good sleep and daily energy. Poor vitamin D levels may increase the risk of insomnia, obstructive sleep apnea, and other sleep issues (26, 27). Vitamin D supplementation may help to improve sleep and reduce fatigue. Supplementing with VIT D may also help to improve fatigue and symptoms in chronic fatigue syndrome (28).

Improved Hormonal Health and Fertility

Are you experiencing symptoms of hormonal imbalance? Vitamin D may be the answer you’ve been looking for — remember, it’s a prohormone! Low vitamin D levels have been linked to endometriosis and polycystic ovarian syndrome (PCOS) (29, 30). Supplementation may help to alleviate symptoms. Vitamin D may help to improve female fertility, pregnancy outcomes, and breastfeeding (31). Men shouldn’t ignore their VIT D levels either as it may support sperm production and motility (32).

Easier Weight Loss

As you learned earlier, people who are obese or overweight, need more vitamin D and are at a higher risk of not meeting their needs (33). Vitamin D alone, of course, won’t make you lose weight (unfortunately!). But research has shown that vitamin D supplementation combined with a healthy diet may support weight loss (34).

Reduced Risk of Cancer

According to the American Cancer Society, 1.9 million new cases of cancer are diagnosed and over 600,000 people die from cancer each year in the United States alone (35). Fortunately, it has shown anti-cancer and cancer-protective properties (36). It may help to inhibit cancer cell growth, support programmed cell death (apoptosis), and decrease the metastatic potential of cancer cells. Studies found that vitamin D deficiency may increase the risk of colon, ovarian, breast, prostate, and other forms of cancer. Higher levels of vitamin D, however, seem to reduce your risks and improve outcomes (37).


Healthy foods containing vitamin D

Food Sources of Vitamin D

Food is not the best source of vitamin D. However, there are some foods that can help to boost your VIT D levels a bit, including:

  • Cod liver oil
  • Fish, including carp fish, mackerel, eel, salmon, swordfish, whitefish, tuna, sardines, and rainbow trout
  • Pasture-raised eggs, especially egg yolk
  • Beef liver
  • Raw milk
  • Caviar
  • Mushrooms, including portobello and maitake
  • Fortified foods, such as cereals and orange juice*

*Note that I do not recommend fortified foods because they tend to be overly processed and full of added sugar, additives, and artificial ingredients.


Woman standing outside in sunshine

Getting Some Sunshine

What about sunshine? As long as the weather allows, I recommend spending time outside and getting some vitamin sun. Try to get at least 15 to 20 minutes a day of sun exposure 3 to 4 times a week. Avoid the midday sun to protect yourself from sunburn and sun damage.

Sunscreen is still important. However, I recommend avoiding commercially available sunblock products that are filled with chemicals, including oxybenzone, avobenzone, ecamsule (aka Mexoryl SX or terephthalylidene dicamphor sulfonic acid), salicylates, menthyl anthranilate, digalloyl trioleate (aka gallic acid or 3-gallate), cinnamates, and PABA esters. Sunscreen alone may not protect you from cancer, however, some of these chemicals may actually increase your risk of allergies, inflammation, cancer, and other health issues (38, 39).

Instead, I recommend using organic-made with natural ingredients, such as coconut oil, jojoba oil, shea butter, eucalyptus oil, and zinc oxide. When applied appropriately, zinc oxide may protect your skin from sun damage.  After getting the 15-20 minutes be sure to protect your skin!


Vitamin D laying on the table. Supplements.

Vitamin D Supplementation

Since protective clothing and sunscreen may reduce the VIT D benefits of the sun, you can’t outsmart supplementation. It’s even more important if you are leading an indoor lifestyle, living in colder or gloomier climates, or have low vitamin D levels.

VIT D supplements are available in two forms: VIT D2 and vitamin D3. Vitamin D2, also known as ergocalciferol or pre-vitamin D, is produced in plants and fungi. However, Vitamin D3, or cholecalciferol, is produced in animals and humans.

Vitamin D3 is more effective than vitamin D2. Though they can both be absorbed into your bloodstream, your liver metabolizes them differently. It metabolizes VIT D2 into 25-hydroxyvitamin D2 and vitamin D3 into 25-hydroxyvitamin D3. These two compounds are called calcifediol, which is the main form of VIT D circulating in your body. Since calcifediol is what gets stored in your body, doctors measure calcifediol levels when looking at your vitamin D status. Research has shown that vitamin D3 may be more effective at raising calcifediol levels in your blood (40, 41, 42).

My Recommendation

I recommend using a Vitamin D3 supplement  combined with vitamin K2. These two vitamins have a synergistic relationship. Together, VIT D3 and K2 promote calcium absorption for bone health without causing calcification (43, 44). Vitamin K2 also helps with normal blood clotting, muscle function, healthy bones, and heart health.

The recommended daily allowance for VIT D is 600 IU for most children and adults between ages 1 and 70, 800 IU for anyone over 70, and 400 IU for babies under 12 months (2). However, considering the benefits of VIT D and the increased risk of deficiencies, functional medicine practitioners tend to recommend a much higher dosage of 5000 IU or more.  And if people have risk factors for low VIT D, they may require higher doses.

I recommend using this Vitamin D3 5000 with 5000 IU (125 mcg) in one capsule. This supplement provides you with a hefty dose of this important nutrient, in our preferred form of vitamin D3.


Next Steps

If you want to improve your health, I welcome you to schedule a functional nutrition consultation with my nutritionist, Sarah. Visit our store for products.

And stay tuned for more information to help you uncover the root cause of your health issues, improve your nutrition, repair your body, and regain your health naturally.

You can schedule your consultation with Sarah here.