Vitamin D becomes a hot topic as the weather starts to get cooler and sunlight levels start to decrease. If you live in a state where the days get shorter, and it’s dark at 4pm, you may have questioned if you’re getting enough Vitamin D. While sunlight does go hand in hand with Vitamin D, there is more to this vitamin than how much sunlight you are getting each day. We break down the top things you need to know about Vitamin D, what to look out for with a deficiency, and information on when you may need to consult a healthcare provider.

What is Vitamin D?

In an article shared by the U.S. Preventative Services Task Force, Vitamin D is defined as “a fat-soluble vitamin that performs an important role in calcium homeostasis and bone metabolism and also affects many other cellular regulatory functions outside the skeletal system.” In simpler terms, Vitamin D plays a role in keeping bones, muscles, and teeth healthy. Vitamin D also reduces inflammation, and regulates cell growth, immune function and glucose metabolization.

Healthy Vitamin D Levels and Vitamin D Deficiencies

According to the National Institutes of Health Office of Dietary Supplements, 15 mcg/600 IU is the daily recommended amount for adults ages 19-69. For adults ages 70 and older, those numbers increase to 20mcg/800 IU. In order to be considered deficient in Vitamin D, a person needs to have lower than these levels for extended periods of time. The groups most at risk for a Vitamin D deficiency include:

  • The elderly
  • Adolescents
  • Obese individuals
  • Individuals with chronic illnesses (ex: diabetes)

The top sources for Vitamin D are food, sunlight, and dietary supplements. While Vitamin D isn’t found in many food groups, fish and fish oils tend to have the highest amounts. There are also small amounts in milk, eggs, and mushrooms. While sunlight helps with Vitamin D levels, certain factors like sunscreen, time spent outdoors, clothing worn and cloud cover can impact the amount of exposure. For dietary supplements, there are several versions of Vitamin D on shelves, and also included in multi-vitamins. The amount of mcg/IU vary, and it’s important to make sure a dietary supplement doesn’t lead to very high levels of Vitamin D consumption. Before adding a Vitamin D supplement to your routine, you’ll want to consult a healthcare provider first to ensure it’s safe for you and won’t interact with any medications you may be taking.

Vitamin D Levels and Seasonal Affective Disorder

Because sunlight is one of the main sources for Vitamin D, people in the Northern Hemisphere may wonder if their levels are suffering due to less sun in the winter months. Additionally, Seasonal Affective Disorder (SAD) is common in individuals who live in those areas.

The National Institute of Mental Health says SAD is a type of depression that has a recurrent seasonal pattern where symptoms last 4-5 months each year. Sometimes SAD is referred to as the “winter blues” as it’s more common in fall and winter, but there are also symptoms of summertime SAD. In addition to symptoms of depression that include feelings of hopelessness, losing interest in activities and low energy levels, winter-specific symptoms of SAD may also include:

  • Oversleeping
  • Overeating (with a strong desire for carbohydrates)
  • Weight gain
  • Social withdrawal

So, is there a connection between Vitamin D levels and SAD? Many studies have been done with different groups of people to better understand any connections. Depending on the type of study, goals for the study, and people involved, the results can be mixed, however there is some correlation between Vitamin D and SAD. Increasing Vitamin D levels, spending more time outdoors (even when it’s cold) and exercise can all help get through the winter blues.

When to Consult Your Healthcare Provider to Test Vitamin D Levels

The National Center for Biotechnology Information says that signs of a Vitamin D deficiency include fatigue, bone pain, increased risk of falls and fragility fractures, and osteoporosis. While many turn to the internet to figure out if they have a medical condition, talking to your healthcare provider is the best first step. After sharing your experience and any symptoms, if your healthcare provider feels a test is necessary, a simple blood test can be ordered to confirm your Vitamin D levels.

Sources:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2908269/

https://www.ncbi.nlm.nih.gov/books/NBK532266/

https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/

https://www.nimh.nih.gov/health/publications/seasonal-affective-disorder