what is the sunshine vitamin?

What is the Sunshine Vitamin?

What is the Sunshine Vitamin?

Have you noticed to be an all around happier person in the summertime? While seasonal depression is real, this sadness felt in the Fall/Winter may actually be a vitamin deficiency from lack of sunshine. This might have you wondering, what is the sunshine vitamin? Sunshine provides vitamin D. After sun exposure, vitamin D is made in our skin. Vitamin D can also come from food sources but most of the time, adequate amounts come from outdoor exposure.

There is a correlation between increased mood & happiness and the sunshine vitamin. Fittingly, vitamin D has earned an additional nickname: the happiness vitamin. The standard recommendation for time in the sun is about 10-30 minutes daily but this may not be possible every day. Luckily, there are other ways to get sufficient vitamin D-like through food intake.

Vitamin D is fat soluble which means the body requires fat intake to absorb this vitamin. To achieve optimal health, adequate vitamin D is essential. Per Mayo Clinic, the recommended daily amount of vitamin D is 400 international units (IU) for children up to age 12 months, 600 IU for people ages 1 to 70 years, and 800 IU for people over 70 years.

Vitamin D Forms

There are two forms of vitamin D: vitamin D2 and vitamin D3. Plants exposed to UV light can provide vitamin D2. Vitamin D3 is the active form in humans and animals when exposed to sunlight. D3 seems to be more effective in humans per recent research. Fortified foods typically contain D2.

Vitamin D Benefits

Calcium and phosphorus absorption is necessary for bone health and vitamin D is required for this process. The sunshine vitamin aids in disease prevention and helps maintain bone and muscle mass. It’s important to note, inflammatory bowel disease can reduce absorption of dietary vitamin D.

One study found that adequate intake of vitamin D during pregnancy decreased risk of bipolar disorder and anxiety neurosis for their offspring.

On top of that, studies have also shown that increasing vitamin D can result in increased cognitive performance. These findings also include improved memory, concentration, and better mood.

This vitamin is essential for the prevention and treatment of depression and chronic pain plus has many other health benefits. Vitamin D receptors stimulate serotonin- the happiness hormone.  Sufficient vitamin D intake can lead to increased happiness and overall improved mental health.

Symptoms of Vitamin D Deficiency

Vitamin D deficiency is pretty common and low levels appear in many American’s blood work regularly, especially in the winter months. Even in the sunniest areas, vitamin D deficiency is common when most of the skin is shielded from the sun.

There is an association between low levels of vitamin D and congestive heart failure, type 2 diabetes, and certain forms of cancer. Interestingly, in a study of men with prostate cancer, the disease developed 3 to 5 years later in the men who worked outdoors than in those who worked indoors. We can’t say for sure, but it is possible the increased vitamin D exposure prolonged the disease.

On top of that, vitamin D deficiency can cause muscle weakness and can weaken bones which can result in fractures. Without the sunshine vitamin, only 10 to 15% of dietary calcium and about 60% of phosphorus is absorbed. As a result, this can lead to even more medical issues including rickets or bone related issues.

Additionally, one study showed that 93% of persons 10 to 65 years of age who were admitted to a hospital emergency department with muscle aches and bone pain and who had a wide variety of diagnoses, including fibromyalgia, chronic fatigue syndrome, and depression, were deficient in vitamin D.

The brain has a receptor for vitamin D so levels are directly related to brain function. A link has been found between vitamin D deficiency and an increased incidence of schizophrenia and depression as well as decreased mood and cognitive performance.

On the other hand, vitamin D supplementation has been proven to improve mood status, anti-inflammatory biomarkers, and anxiety. We can absorb adequate amounts of the sunshine vitamin through being outside but there are also high vitamin D food choices when time outside is not realistic.

Sources of Vitamin D

There’s always the option to supplement vitamin D. As a Registered Dietitian, I recommend trying to obtain adequate amounts through diet. As always, talk to your healthcare provider about what’s best for you.

A few examples of high vitamin D foods include:

  • Milk
  • Fortified Milk Substitutes
  • Spinach
  • Fatty Fish (Salmon, Sardines, Herring, Tuna, Trout)
  • Eggs
  • Fortified cereal
  • Mushrooms (treated with UV light)
  • Fortified Orange Juice
  • Pork
  • Fortified Yogurt
  • Cod Liver Oil
  • Cheese (specifically Meunster, Fontina, Monterey, Ricotta)
  • Beef Liver
  • Fortified Tofu
Photo by Nikolai Chernichenko 


It’s important to note that increased sun exposure won’t lead to a toxic level of vitamin D as the kidneys tightly regulate levels in the blood. However, excessive intake of vitamin D can lead to hypercalcemia or hyperphosphatemia but this would require about 50,000 IU intake daily.

Moreover, it’s extremely important to monitor your own vitamin D levels through blood work to determine the need to increase vitamin D food choices, sunlight, or supplementation.

So, in the days or seasons it’s not possible to receive adequate vitamin D from sunlight consider focusing on increased intake of foods that provide vitamin D to prevent deficiency leading to decreased mood.

Check out my Tuscan Salmon recipe– a meal packed with vitamin D.


Holick, Michael F. “Vitamin D deficiency.” New England journal of medicine 357.3 (2007): 266-281.

Wilkins, Consuelo H., et al. “Vitamin D deficiency is associated with low mood and worse cognitive performance in older adults.” The American journal of geriatric psychiatry 14.12 (2006): 1032-1040.

Peterson, Amie L., et al. “Memory, mood, and vitamin D in persons with Parkinson’s disease.” Journal of Parkinson’s disease 3.4 (2013): 547-555.

Penckofer, Sue, et al. “Vitamin D supplementation improves mood in women with type 2 diabetes.” Journal of diabetes research (2017).

Grant, William B., and Michael F. Holick. “Benefits and requirements of vitamin D for optimal health: a review.” Altern Med Rev 10.2 (2005): 94-111.

Vitamin D. Mayo Clinic. Feb 9 2021. https://www.mayoclinic.org/drugs-supplements-vitamin-d/art-20363792

Armas, Laura AG, Bruce W. Hollis, and Robert P. Heaney. “Vitamin D2 is much less effective than vitamin D3 in humans.” The Journal of Clinical Endocrinology & Metabolism 89.11 (2004): 5387-5391.

Vitamin D Fact Sheet for Health Professionals. National Institutes of Health. Aug 21, 2021. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/

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