Do you live in a place that turns cloudy and gray for weeks on end in the winter? Do you often wear sunscreen or protective clothing and hats in the summer? Have you recently been pregnant or breastfeeding? Do you spend less time in the sun than you used to?

Our bodies produce vitamin D₃ through exposure to the sun, and is a building block for an important steroid hormone in your body called calcitriol. Vitamin D₃ works with other hormones to support healthy bones, cell growth and is a key factor in maintaining hormonal balance and a strong immune system.

I recently had my vitamin D levels tested. Not surprisingly, I was in the deficiency range. I live in the rainy part of the Pacific Northwest and am breastfeeding a toddler. My doctor said that almost everyone she tests in our region of the county is somewhat deficient. When I told my family who live in sunny Texas about vitamin D deficiency, they also got checked. And guess what? They too also tested as deficient! Why? That Texas heat keeps people indoors, close to the A/C. So, even if you live somewhere with year-round sun, you might still need some help getting enough vitamin D - and not doing so can impact everything from your bone health to your sleep patterns. This typically means two things: Making sure you get enough daily sun exposure (without sunscreen) and taking a Vitamin D supplement.

But why a supplement? Shouldn't we just be able to boost our vitamin D levels through dietary changes? Or from the sun?

We do get some vitamin D in fortified food sources like milk and cereal. It is also naturally occurring in egg yolk and fish oils. But those those sources are not enough. Our bodies are used to getting Vitamin D from the sun. Studies show that people today stay indoors more, get less exercise and wear more sunscreen, leading to less sun exposure. Sunscreen, especially with a SPF rating greater than 8, effectively blocks synthesis of vitamin D in the skin. Pregnancy and breastfeeding also draw down the body’s vitamin D stores.

Research also shows that vitamin D deficiency leads to increased risk of many cancers and heart disease, not to mention lowered immune functioning, sleep dysfunction and increases in chronic pain. It is also suspected to contribute to many autoimmune diseases and Autism.

You can have your vitamin D levels checked with the 25-hydroxyvitamin D test, also called a 25(OH)D. This requires a simple blood draw and is covered by most health insurance. For both children and adults, levels should be above 50 ng/ml year-round. It took almost a month for my results to come back and when I called the lab, they said that so many people are getting this test done that they were struggling to keep up with demand. And Quest Diagnostic Labs, the nation’s largest medical laboratory, recently admitted that they might have made errors in thousands of test results over the past two years.

It is important to work with your health care provider to determine your vitamin D needs. Toxicity can occur with long-term high doses of vitamin D. While this is a rare occurrence, it can make you sick. Vitamin D is fat soluble and not excreted as easily as many other supplements.

You should also do some research and be informed before you approach your doctor about supplementing vitamin D. I was nervous about taking “too much” and only supplemented 2000 iu of D3 per day after finding out I was deficient. When I had my blood work rechecked four months later, there was no change in my levels. This is because 2000 iu is only enough to maintain levels for a breastfeeding mother but not enough to actually raise them. Now after taking 5000 iu for three months, my levels are close to the normal range. If you feel you are at risk for deficiency, it is advisable to test your levels even if you are currently supplementing. This way, you can determine if you are indeed taking enough to meet your own body’s needs. I found the Vitamin D Council to be a good source of research-based information.

Be sure that your children are getting enough vitamin D as well. Last year, the American Academy of Pediatrics doubled the recommended dosage of daily D for children and breast-fed babies. The new recommendation is 400 iu per day. Formula-fed babies get vitamin D in their milk. And remember, these dosages are for children who are not already deficient and who get some sun exposure. Your baby or child might need more. As always, check with your health care provider before changing or adding any supplements.

Besides supplementing D₃, you can also expose yourself to direct sunlight for 20 minutes daily. Make sure you have some skin exposed in order to soak in the sunlight! Sit by a window, go for a walk, play in your garden or at the park. If you can make significant lifestyle changes, you may do a couple of rounds of testing and decide that supplementation isn't necessary.

For our family, supplementing D₃ has made a huge overall improvement in our sleep. As for myself, I feel less achy and my immune system is functioning better! A simple blood test and an inexpensive supplement has made a lot of difference.