Are you low on vitamin D? Experts say deficiency could increase susceptibility to illness

The northern latitude in North Dakota and Minnesota mean that during the winter, the sun’s rays are so weak that they don’t allow people to make vitamin D, increasing the risk of deficiency.

A smiling woman with wavy blond hair stands in the sun.
Beth Sanford of Rasmussen University stands in the sun — necessary for the body to produce vitamin D — Wednesday, March 22, 2023, in Fargo. She is directing the Vitamin D Project in North Dakota to educate people about the importance of Vitamin D for good health.
Michael Vosburg / The Forum

FARGO — Beth Sanford’s daughter found herself in a downward health spiral. Her symptoms started with a run-down feeling, which she attributed to her exertion from running cross-country.

As weeks passed, the high school student was unable to recover. Her fatigue grew worse, and she was prone to infections.

“She started to get cold after cold after cold,” Sanford said, recalling the episode in the fall of 2019. “That’s not her at all. Very healthy kid.”

The slide continued. Her daughter became worried and unusually emotional, telling her mother: “‘Mom, I feel like I’m dying. There’s something wrong with me. I don't feel like myself.”

At the suggestion of a nurse-practitioner friend, Sanford had her daughter's vitamin D levels checked and learned they were low: 8 nanograms per milliliter, far below the 40 to 60 considered normal by vitamin D experts.


Anything below a level of 20, according to the National Academy of Sciences, is considered deficient.

After three months of taking vitamin D, Sanford's daughter tested at 22. Her levels later climbed higher, and she regained her health.

The experience made a believer of Sanford, a nurse who went on to launch what she calls the North Dakota Vitamin D Project to survey vitamin D blood levels in North Dakota. She found out that her daughter wasn’t alone — lots of people were deficient.

Her survey of 49 people in late December 2021 to February 2022 found that almost half of the participants had vitamin D blood levels below 20 nanograms per milliliter — and one in five had levels below 10.

Only one participant had a level within the range of 40 to 60 nanograms per milliliter recommended by a panel of 48 international vitamin D researchers and scientists.

The northern latitude in North Dakota and Minnesota mean that during the winter, the sun’s rays are so weak that they don’t allow people to make vitamin D.

“We have a big problem in North Dakota,” Sanford said. Those who have dark skin, wear clothing that covers most of their body, eat a plant-based diet or are older are more likely to be deficient.

Even when the sun is more robust, the peak time for absorbing the ultraviolet rays that allow the body to make vitamin D is between 10 a.m. and 2 p.m. — a period when many are indoors at work, said Sanford, who teaches nursing at Rasmussen University in Fargo.


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Sanford’s survey of vitamin D status was a project for her doctorate in nursing practice, which focuses on bringing health research into clinical practice. Her work continues in collaboration with GrassrootsHealth Nutrient Research Institute , a nonprofit that works to move vitamin D research into practice.

To increase awareness of the health benefits of maintaining adequate vitamin D levels, Sanford works with health care professionals in the area, many of whom haven’t received training in nutrition.

“Our practitioners just aren’t very confident in their vitamin D knowledge,” she said.

After seeing the difference in her daughter’s health, Sanford has worked to maintain her own vitamin D levels. She strives for a level of 60 nanograms per milliliter, which research has shown can help prevent cancer.

“I’ve been very amazed at the difference in my ability to focus,” she said. Before taking vitamin D supplements, she suffered from fibromyalgia symptoms, including pain and migraine headaches.

“I actually don’t have pain anymore — none,” Sanford said. “I don’t have to take pain medication anymore.”

It’s long been known that there’s a causal link between a severe vitamin D deficiency and rickets, a bone disease. A link also has been shown between vitamin D insufficiency and osteoporosis and associated decreased muscle strength, as well as increased risk of falls, according to GrassrootsHealth.

More recently, research has shown associations between vitamin D deficiency and many other diseases, including tuberculosis, psoriasis, multiple sclerosis, inflammatory bowel disease, Type 1 diabetes, high blood pressure, heart failure, myopathy and breast and other cancers, research cited by GrassrootsHealth indicates .


Vibra Hospital of Fargo, a specialty hospital within Sanford Medical Center that cares for critically ill patients, has begun monitoring the vitamin D status of patients and giving supplements to address deficiencies.

“We are monitoring it on all of our patients,” said Bonnie Vangerud, Vibra’s chief clinical officer. “We decided it would be an excellent quality improvement program.”

Vibra’s goal is to bring all patients to the recommended blood level of 40 to 60 nanograms per milliliter — and they're finding that many patients are deficient.

“Many of them are in the 10 range,” Vangerud said. Vibra patients, most transferred from other hospitals, have an average length of stay of 25 to 30 days and often come with many coexisting illnesses, including respiratory illnesses, trauma, traumatic brain injury or stroke.

Many are given intravenous antibiotics, and Vibra is interested to see if maintaining vitamin D levels can reduce infections, as research has shown.

Also, research has shown that maintaining vitamin D levels decreased the use of opioid pain medication, increased wound healing and decreased hospital-acquired infections, Vangerud said.

“We are very, very hopeful that our outcomes will increase,” she said, noting the monitoring has just started.

Further research shows maintaining proper vitamin D levels can reduce health care costs, Vangerud said. “Not only is it good for the patient,” she said, “it’s good for health care. It’s very cost-effective.”


Vangerud, who is a nurse, said people should ask their primary care provider to test their vitamin D levels to find out if they are deficient.

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William Grant, an independent vitamin D researcher in San Francisco who has published 35 research papers, studied the association of low ultraviolet sunlight exposure with several cancers, including breast cancer, colon cancer and ovarian cancer.

Those cancers are more prevalent in higher latitudes, where ultraviolet sunlight exposure is lower, especially in the winter months, said Grant, who considers blood levels of 40 to 60 nanograms per milliliter to be optimal.

Because of the lower exposure to ultraviolet rays in sunlight, residents of states like North Dakota and Minnesota are at higher risk for diseases that can be prevented by maintaining adequate vitamin D levels, he said.

“It’s among the lowest in the country,” Grant said of ultraviolet sunlight in the region.

Researchers in Canada found study subjects eliminated their high blood pressure when they raised their blood levels of vitamin D to more than 40, he said.

Vitamin D can reduce inflammation, which is involved in many diseases, Grant said. Veterans Affairs hospitals regularly measure vitamin D levels and have found blood levels of 30 nanograms per milliliter or more were associated with reduced COVID-19 and heart problems, he said.

It appears that vitamin D can reduce cancer risk by reducing a process called angiogenesis, the formation of blood vessels that nourish tumors, which helps to prevent cancers from spreading, Grant said.


Sanford, who considers herself a vitamin D evangelist, works as a research and quality improvement consultant for vitamin D evidence-based practices.

She’s co-author of a study published in Nutrients, a peer-reviewed journal, that found vitamin D deficiency — levels below 20 nanograms per milliliter — is common among pregnant women and is connected with many health problems during pregnancy, including gestational diabetes and preeclampsia, a high blood-pressure disorder that can develop during pregnancy.

In collaboration with researchers, Sanford wants to devise vitamin D recommendations for the Northern Plains region as a determinant of health. Regional recommendations are important because ultraviolet sunlight exposure and other factors vary by region, she said.

But risks also vary widely among individuals, so recommendations must be tailored.

“We could see dramatic ... prenatal outcomes,” she said. “We can affect our population health and move the marker. This is a modifiable risk factor.”

Interested in participating in the North Dakota Vitamin D project?

Sanford is continuing to collect information about vitamin D levels in North Dakota residents. Those who would like to participate can go online to order a home test kit . GrassrootsHealth compiles the results by state.

Patrick Springer first joined The Forum in 1985. He covers a wide range of subjects including health care, energy and population trends. Email address:
Phone: 701-367-5294
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