Health & Wellness
Get Your Daily Dose of Vitamin D

Get Your Daily Dose of Vitamin D

Learn how much vitamin D your body needs and the risks of deficiency.


by Morgan A. McLaughlin McFarland

Vitamin D is an essential component in absorbing calcium to the body and preventing several serious health problems. Our own bodies actually produce this vitamin, yet vitamin D deficiency has become widespread in the United States. Vitamin D deficiency has no reliable symptoms, either, so an inadequate amount of vitamin D could go undetected for years. Learn what you might be risking if your levels are low, and be sure to get a vitamin D test – a simple blood test – at your next annual check-up.

The Dangers of Deficiency

Vitamin D is a vital component for health. Without it, the body cannot absorb calcium. Rickets – a condition where the bones don't have adequate calcium and become deformed and at increased risk of fracture – is one major condition that can result from a lack of vitamin D. Dr. Richard Hansen, Director of Primary Care at Emory Specialty Associates, also lists kidney disease and psoriasis as conditions with strong evidence linking them to vitamin D deficiency. While studies have not yet shown a significant link, researchers are also examining possible correlations between vitamin D and autoimmune diseases, cancer prevention, cognition, fertility, fibromyalgia, high blood pressure, mood disorders, multiple sclerosis, arthritis, stroke and diabetes.

Dr. Richard Ellin, a primary care physician with Kaiser Permanente, says other studies are exploring links between vitamin D deficiency and "certain vaginal infections in pregnant women, fetal loss, cognitive decline, seasonal depression, and increased gastrointestinal and ear infections in children, among other things." Though these studies are only preliminary, they do strongly suggest that vitamin D deficiency can have an impact on the entire body.

Risk Factors

Some risk factors for deficiency are beyond our control. Because melanin offers natural protection against the sun's UVB rays, darker skinned individuals absorb less sun and thus produce less vitamin D. Age is another factor; as we age, less vitamin D is absorbed in the intestines from food or supplementation.

Seasons and location also play a role in vitamin D production; our bodies are less able to manufacture vitamin D in the winter and at higher latitudes, due to the angle of the sun's rays.

Some risk factors can be influenced and changed, such as weight. Vitamin D is a fat soluble nutrient, meaning that excess body fat can absorb vitamin D and prevent it from going where it's needed. Reducing body fat can help you better use the vitamin D you take in.

Even something as simple as an increase in indoor activities and can put you at risk. "With group fitness classes and boutique specialized gyms on the rise, more and more people are working out indoors rather than outside," says Jennifer McGlown, Inpatient Clinical Nutrition Coordinator at Northside Hospital.

Whether your risk factors can be changed or not, vitamin D deficiency can be reduced in several ways, many of them as simple as taking a short walk outside or making small, but important, alterations to your diet.

Let the Sun Shine In... Safely

What is one of the greatest factors in our natural trend toward vitamin D deficiency? The answer may be a surprise: sunscreen. In our quest to prevent skin cancer, we've cut ourselves off from the most significant natural source of vitamin D: the sun.

"The major source of vitamin D for humans is exposure to sunlight," says Kathy Taylor, the director of nutrition services at Grady. "Anything that decreases the penetration of solar radiation into the skin will affect the synthesis of vitamin D. Sunscreen and sun protection when applied properly decrease the penetration of solar radiation, thus decreasing synthesis of vitamin D."

"People are more diligent about applying sunscreen, and at any SPF greater than 8, you are blocking UVB rays," adds Dr. Sharon Bergquist with Emory Healthcare. She also notes that because of the sun's cancer-causing effects, recommending more sun exposure is a controversial issue for health care providers.

SB-001If consistent sunscreen use is partially to blame for the rise in vitamin D deficiency, but failure to use sunscreen increases the risk of skin cancer, how can we safely intake enough vitamin D to keep us healthy? Luckily, concerns over sun exposure and vitamin D intake don't have to be mutually exclusive.

"Early morning sunlight is the best way to get exposed to Vitamin D. It's safe and not harmful to the skin," says Dr. Saju Mathew, a Family Medicine specialist with Piedmont Physicians. Dr. Zach Cohen, with the Atlanta Center For Holistic & Integrative Medicine, agrees that safe sun exposure can make a significant impact on vitamin D levels.

"If we all got about 15 minutes of unfiltered (no sunscreen) sunlight to the arms, hands and trunk 2-3 times per week, I think the incidence of vitamin D deficiency would decrease," says Dr. Cohen, who added that he doesn't recommend unfiltered sunlight to the face or scalp, suggesting a wide-brimmed hat and SPF-protective clothing, and reminds us to cover up after our 15 minutes of sun.

From the Inside Out

Many doctors and nutritionists also recommend oral supplementation as the safest and most reliable way to ensure an adequate vitamin D level. The first step in knowing if supplementation is needed (and if so, how much) is the blood test performed by your primary care physician. The normal range for vitamin D is between 20 and 50 nanograms per milliliter.

In the case of patients who turn out to have a slight deficiency or whose vitamin D levels are on the low side a normal, a daily dose of 2000 IU of vitamin D is the common course of treatment.

Along with supplementation, vitamin D can be improved through diet. Cold-water fish like salmon, mackerel and tuna contain vitamin D in their naturally occurring oils. Many commercially available dairy products have been supplemented with vitamin D, including varieties of milk, yogurt and cheese. Vitamin D can also be found in egg yolks and beef liver. If diet and sun exposure alone are enough to bring your vitamin D levels within a normal range, supplementation shouldn't be necessary.

Enough is Enough

If a yearly blood test indicates normal, healthy vitamin D levels, supplementation typically isn't necessary. In fact, while higher-than-recommended levels of vitamin D aren't toxic, taking too much vitamin D can have negative long term effects on health.

"Because we've done a decent job trying to get message out, people are taking supplements and we're starting to see the opposite problem, with too high a level of vitamin D," says Dr. Bergquist. "There's a sweet spot, probably between 30 to 50 nanograms per milliliter. When you go above 50, it can start to work against you!" So before supplementing on your own, altering your diet or basking in the sun too long, check with your doctor about your current vitamin D levels and the best course of action.


Editorial Resources

Sharon Bergquist, MD, Emory Healthcare –

Zach Cohen, MD, Atlanta Center for Holistic & Integrative Medicine –

Richard Ellin, MD, Kaiser Permanente Alpharetta Medical Center –

Richard Hansen, MD, FACP, ESA Primary Care Division –

Jennifer McGlown, RDN ,LD, CDE, Northside Hospital –

Saju Mathew, MD, Piedmont Physicians –

Kathy Taylor, Grady Health System –