Sunshine and Vitamin D: Exploring Vitamin D Deficiency and Supplementation
By: Grace Valentine

Image by: @seantookthese
With summer officially here, we are all dreaming of beach days and getting our dose of sunshine and vitamin D.
Vitamin D gets its namesake mainly because it can be absorbed through the skin when exposed to sunlight and converted in the kidney to a usable form in the body. Most people think that simply going outside will give them enough Vitamin D to meet their needs, but evidence shows that is not the case for many.
A study in Nutrition Journal found that 48% of Americans are deficient in Vitamin D. This deficiency holds, even in sunshine states like Florida and California. Vitamin D comes from UVB, which is time, season and latitude dependent. This type of ray can represent less than 5% of total sunshine.
Research shows that getting enough Vitamin D may help prevent or decrease the severity of respiratory infections, like seasonal cold and flu. With infection rates of COVID-19 spiking again, preparing our immune system with appropriate levels of Vitamin D intake is critical.
For those who can convert Vitamin D to Vitamin D3 through sun exposure, time outside can be enough. Regular exposure by walking or exercising outside for a few minutes every day is a great way to get some sunshine and vitamin D. Location and season play a role.
For those whose bodies cannot convert sunshine to vitamin D or simply live in a less than sunny climate, vitamin D intake through supplementation may be necessary to optimize immunity. When it comes to vitamins, how much, and what type are personal decisions.
Vitamin D Deficiency
Symptoms of Vitamin D Deficiency:
- Fatigue
- Muscle weakness and pain
- Hair Loss
- Decreased structural integrity of bone
- Disordered parathyroid function
- Lung infections and immune system disorders
- Depression
A deficiency in vitamin D can cause one to experience fatigue, pain in muscles or bones, impaired wound healing, hair loss, malaise, and even depression. In children, inadequate levels of vitamin D can lead to rickets, but most often present as muscle soreness or pain. In adults, diagnosis is not as obvious. However, physicians can easily test for vitamin D deficiency with a blood sample or, if necessary, they may request an x-ray to look for structural abnormalities in the bone.
Though there is a link between sunshine and vitamin D, sunlight will likely not be adequate. This is particularly true among those who lack the enzyme to convert Vitamin D from the sun into the usable form in the body. Vitamin D naturally occurs in some food sources, including salmon, egg yolk, and fortified cereals. However, most Americans show consistently low levels of Vitamin D, likely due to lack of variety in their diets. Fortunately, this is easily remedied by supplementation.
A recent Finnish study found that Vitamin D supplementation can reduce the risk of respiratory tract infections by 50% in those who are deficient and by 10% in those with adequate levels of Vitamin D. This finding is especially important when faced with a pandemic like COVID19 that effects the respiratory system.
Dr. Rhoda Patrick trained at UCSD and Children’s Hospital Oakland Research Institute and is the founder of Found My Fitness.
Seasonal Blues
Many people in the Northeast struggle with seasonal depression due to inadequate sunshine and vitamin D. Supplementation with vitamin D can help reduce the risk of development or severity of depression in some cases. The importance of vitamin D supplementation in geographic regions with low sun exposure is so critical that legislators in Alaska have even advocated for supplementation to help their residents regulate seasonal depression.
Evidence supports that even those who live in primarily sunny climates can still suffer from depression due to deficiency. Check out this podcast from experts at Johns Hopkins. They navigate vitamin D complexities and discuss when vitamin D supplementation is appropriate and what levels of vitamin D are most advantageous.
Benefits of Supplementation
It’s been proven that sunshine and vitamin D are important, it’s best not to count on sunlight for all your vitamin D needs.
Optimizing vitamin D levels through appropriate supplementation improves metabolic regulation across all body systems, protecting against and treating many conditions. Benefits include:
- Improved kidney function
- Improved muscular repair
- Improved immune function
- Improved deposition of bone
- Regulation of diabetic dysmetabolim
- Improved heart health
- Optimal parathyroid regulation
- Decreased blood pressure
- Decreased risk of certain cancers
Nutrient Dependencies
Deficiency is complex and therefore cannot be chalked up to lack of sunshine and vitamin D.There are several key minerals along with vitamin D that are interdependent. Calcium and phosphorus round out the trifecta, as they are critical to appropriate skeletal and muscle repair.
There several other key minerals that play an important role in the initiation of biological processes dependent on vitamin D. Magnesium assists in the activation of Vitamin D, which is necessary for the body to utilize and process vitamin D. Zinc works in concert with Vitamin D to improve immune function and prevent illness. Deficiency in any of these key nutrients is associated with skeletal abnormalities, cardiovascular disease, metabolic syndrome, and reduced immune function.
Magnesium
Enzymes that convert vitamin D in the liver and kidneys to its usable form are magnesium-dependent. Magnesium is the trigger point for all subsequent processes in the parathyroid, gut, kidneys, liver, and skeletal systems. Without appropriate levels of magnesium, vitamin D conversion and the subsequent metabolic processes are inhibited, leading to symptoms of metabolic dysregulation.
Calcium
Vitamin D and calcium work in concert to increase absorption at the gut and maintain appropriate metabolic regulation. As vitamin D bioavailability increases, metabolism of calcium is triggered, leading to the appropriate transfer and deposition of calcium. Among those who are vitamin D deficient, consuming calcium with vitamin D supplements can support enhanced absorption and lead to improved structural deposition, muscular function, and immune response.
Phosphorus
Calcium and phosphorus work together to build bone and repair muscles. They work in tandem, but in opposing directions. When calcium levels rise, phosphorus levels decline. This process is regulated by the parathyroid and is highly dependent on the availability of vitamin D.
Zinc
Zinc acts as the key that unlocks our cells to this metabolic process so that all other processes described above can occur. It is the bridge that allows for transfer and communication between cells. The relationship between vitamin D and zinc is the biological basis for resistance to infection and appropriate immune response. Check out our blog on zinc for more!
Food Pairings
Deficiency goes much deeper than examining the link between sunshine and vitamin D. Macronutrient and micronutrient variety is critical to overall health. Maintaining a well-balanced diet has been associated with improved outcomes across the spectrum. Understanding codependency of micronutrients is important to reaching optimal health. Intentional decision making when it comes to diet leads to positive outcomes.
Food pairings strategies are a fun, simple way to ensure you are getting enough nutrients from your food. These strategies are particularly ideal when the body is in a state of deficiency. Certain food pairings lead to enhanced absorption in the gut, which can address underlying metabolic dysregulation.
Supplementing with vitamin D while consuming a diet with adequate magnesium, calcium and zinc can provide an environment for optimal health.
Food pairing recipes coming soon on our blog!
More Than Just Sunshine and Vitamin D – Dosage
Vitamins A, D, E, and K are fat-soluble vitamins. Toxicity is rare, proving the complex relationship between sunshine and vitamin D, but possible.
More is not necessarily better. In fact, high doses of fat-soluble Vitamins have not proven greater benefit, so it’s best to stick to the RDA of 600 UI for women of childbearing age, according to the NIH.
Pregnancy and Vitamin D
A child’s first 1000 days, starting at conception through a child’s second birthday, is critical in laying the foundation for a healthy lifestyle later in life. A mother’s health prior to pregnancy is crucial to ensuring an optimal nutritional environment for the fetus to grow and thrive.
The metabolization of vitamin D is especially important during pregnancy. Its intricate relationship to other nutrients and subsequent physiological functions are dependent on adequate levels. The evidence of this cascade effect is even more apparent in pregnancy as opposed to other stages of life.
vitamin D deficiency is associated with increased risk of preeclampsia in the mother and preterm birth, low birth weight, and disordered metabolic conditions, such as Type 1 Diabetes and asthma, in the baby’s early stages.
A recent study demonstrated that vitamin D deficient mothers had a 34% higher risk of having a child with ADHD than mothers with appropriate vitamin D levels. Supplementation during pregnancy and while breastfeeding can significantly reduce the risk of complications.
Dosage of Vitamin D in Pregnancy
Dosage navigation is especially important during pregnancy. As discussed, trusting the relationship between sunshine and vitamin D is likely not enough to produce adequate levels of the vitamin in the body.
The RDA is 600 UI in pregnancy, but most prenatal supplements contain 400 UI.
Garden of Life MyKind Prenatal Multi Gummy is one of the few prenatal vitamins that offer the full recommended amount for vitamin D in pregnancy. Rainbow Light Prenatal One comes in at a lower dose with 400UI.
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