Many people understand that vitamin D matters, but few realize just how widespread deficiency still is, especially in places with limited sunlight. In northern states like North Dakota, long winters mean very little UVB exposure, making it difficult to produce adequate vitamin D from sunlight alone.
For hospital patients who haven’t been outside in weeks, low vitamin D levels are almost certain. And while most associate vitamin D with bone health, it also affects the immune system and how well patients recover from illness. This is what led Vibra Hospital in Fargo, North Dakota, to launch a focused vitamin D program.
In the featured video above from GrassrootsHealth, Bonnie Vangerud, chief clinical officer at Vibra Hospital, and Kristen Schimmel, education coordinator at the same facility, explained how they introduced a vitamin D protocol for their long-term care patients, which led to measurable improvements, from stronger immune responses to better recovery outcomes.1
Improving Recovery Through a Structured Vitamin D Program
To combat the consistently low vitamin D levels seen in newly admitted patients, many of whom arrived after extended stays in other facilities with little to no sun exposure, Vibra Hospital implemented a structured protocol that combined testing, personalized dosing, and follow-up monitoring.
The goal was to restore each patient’s serum vitamin D levels to a therapeutic target of 50 nanograms per milliliter (ng/mL), which was associated with stronger immune function and improved recovery.2
• Each patient was tested on admission, with customized dosing based on results — Exclusion criteria were carefully defined to avoid complications in patients with conditions like sarcoidosis, hypercalcemia, or advanced kidney disease. Schimmel explained:
“Upon admission, we do a serum blood draw, included with all of their other lab work that we’re drawing to check out what their vitamin D level is. Our dietitian then takes that serum level and plugs it into the GrassrootsHealth calculator, that online tool to establish their bolus dose, as well as a maintenance dose.
So, from that value, she discusses with the physician, who can then in turn order the vitamin D that is needed. We do follow-up levels at either day 25 or upon discharge, if they’re discharging more at that 3-month mark.
But we do want to catch them before they leave here, so that’s why we implemented that 25-day recheck. At three months, we recheck their vitamin D level, and we can adjust accordingly if it’s a little bit higher than the calculator is aiming towards or if it’s still on that lower side to do that monitored lab value.”3
• Nearly half of patients had dangerously low vitamin D levels — Their data revealed that 44% of patients had vitamin D levels under 20 ng/mL, with 12% falling below 10 ng/mL — and in some cases, levels were so low they couldn’t be detected at all. These findings revealed a glaring oversight in conventional hospital care, where vitamin D status is often ignored despite its wide-reaching effects on health.
• Hospital-acquired infections dropped to zero after vitamin D correction — Central line-associated bloodstream infections (CLABSIs), which had ranged from two to four annually, dropped to zero in 2024.
Catheter-associated urinary tract infections (CAUTIs) also declined sharply, including one full year without a single recorded case. While other infection control strategies, like updated hygiene protocols and earlier catheter removal, played a role, many staff members felt strongly that restoring vitamin D levels was a key factor in the downward trend.
• Additional benefits emerged in areas unrelated to infection — Vangerud noted that a wound care nurse saw patients healing noticeably faster. She also shared the case of a brain-injured patient who was unresponsive and ventilator-dependent, but after receiving vitamin D as part of the protocol, regained consciousness and progressed to rehabilitation. A previous article on the vitamin D program at Vibra Hospital also noted:
“The hospital also saw decreased re-admittance to a higher level of care, an increased number of patients discharged to home or rehab, decreased discharges to skilled nursing facilities, and decreased overall length of hospital stay.”4
• No toxicity occurred even with high-dose supplementation — Some patients received up to 50,000 IU every 48 hours for several weeks without any signs of toxicity. These levels were carefully guided by lab values and adjusted as needed, underscoring the importance of close monitoring and individualized care.
• The impact of the program extended beyond patient care — Staff members began testing their own vitamin D levels and adjusting their supplementation after seeing the benefits firsthand. International nurses who had relocated from sun-filled regions like the Philippines and Africa shared how their moods had changed during the sunless North Dakota winters and how those symptoms eased once their vitamin D levels were restored.
• The hospital’s success was recognized at the state level — Following the program’s implementation, Vibra Hospital received a letter from the North Dakota Department of Health and Human Services acknowledging its dramatic reduction in hospital-acquired infections. The recognition credited the team’s efforts in creating a safer care environment for patients across the state.5
• This approach is simple, safe, and effective — Reflecting on the program’s success, Vangerud stated:
“Vitamin D is very inexpensive, and evidence has shown it has proven outcomes, so why wouldn’t you want to do that for your patients? Give them every possible chance of recovery and resistance to infection. It’s easy, and it’s not harmful … it’s the right thing.”6
What Are the Other Benefits of Vitamin D for Your Health?
Beyond the clinical outcomes already observed in Vibra Hospital’s program, a growing body of research continues to support vitamin D’s broader role in whole-body health. Some of its benefits include:
• Improves muscle strength and physical function — Vitamin D receptors are present in muscle tissue, and deficiency is linked to muscle weakness, falls, and frailty, especially in older adults or those confined to hospital beds. Adequate levels improve muscle protein synthesis, coordination, and recovery from injury.7,8
• Supports cardiovascular health — One of vitamin D’s most important roles in heart health is managing calcium distribution. Without enough vitamin D, calcium is more likely to deposit in blood vessel walls, raising the risk of hypertension, arterial calcification, and cardiovascular disease. Deficiency has been consistently linked to higher rates of heart attack, stroke, and metabolic syndrome.9,10,11
• Protects cognitive function — Vitamin D helps regulate neurotrophic factors like nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), which protect neurons and support synaptic plasticity. Studies link low vitamin D levels with greater risk of dementia, Alzheimer’s disease, and age-related cognitive decline.12,13
• Regulates autoimmune activity — Vitamin D is essential for maintaining immune system balance and plays a key role in regulating T cell differentiation, helping the body distinguish between harmful invaders and its own healthy tissues. Studies link low vitamin D levels to increased risk and severity of autoimmune conditions like multiple sclerosis, rheumatoid arthritis, and lupus.14
• Improves blood sugar control and metabolic resilience — Vitamin D affects insulin sensitivity and glucose metabolism by acting on pancreatic β-cells and modulating inflammatory signals linked to insulin resistance. Clinical trials have shown that supplementation improves fasting glucose and HbA1c levels in patients with prediabetes or Type 2 diabetes, especially when baseline vitamin D levels are low.15,16
• Reduces risk of certain cancers — Vitamin D influences cell proliferation, differentiation, and apoptosis, which are key mechanisms involved in cancer development. Epidemiological data suggest that people with higher vitamin D levels have lower rates of several cancers, particularly colorectal, breast, and prostate cancer.17,18,19
• Supports hormonal balance and thyroid health — Vitamin D receptors are expressed in many hormone-producing tissues, including the thyroid, ovaries, and adrenal glands.20 Low vitamin D has been linked to thyroid autoimmunity, especially Hashimoto’s thyroiditis,21 as well as polycystic ovary syndrome (PCOS) and menstrual irregularities.22
• Promotes gut barrier integrity — Vitamin D helps maintain tight junctions in the intestinal lining, reducing gut permeability, a known contributor to systemic inflammation and chronic illness.23 It also influences microbiome composition by supporting the growth of beneficial bacteria and controlling overgrowth of pathogens.24,25
To learn more about how this essential nutrient impacts nearly every system in your body, read “Everything You Need to Know About Vitamin D for Your Health.”
Are You at Risk of Vitamin D Deficiency?
Whether it’s from sunlight, supplements, or both, keeping your vitamin D levels in the optimal range is essential. But how do you know if you’re getting enough? Some people are more likely to fall short, even with sun exposure or dietary intake. You may be at risk for vitamin D deficiency if:
• You have darker skin — Higher melanin levels naturally protect against UV radiation, but they also reduce your skin’s ability to produce vitamin D. That means you need more sun exposure to generate the same amount as someone with lighter skin.
• You’re over age 60 — Aging skin loses its efficiency in converting sunlight into vitamin D. Even with time outdoors, older adults often struggle to maintain adequate levels without supplementation.26
• You live far north — If you live in northern regions like Canada, Scandinavia, or the northern U.S., the winter sun simply doesn’t provide enough UV rays to support vitamin D production for several months each year.
• You cover your skin or stay indoors — Sunscreen, clothing, or limited time outdoors limits UVB exposure and sharply reduces vitamin D synthesis.
• You have chronic health conditions — Certain health issues interfere with vitamin D metabolism. For instance, obesity traps vitamin D in fat cells, making it less available for use, while gut disorders like celiac or Crohn’s disease reduce absorption from food or supplements.
How to Get the Most Health Benefits from Sun Exposure
There are two main ways to maintain healthy vitamin D levels — sunlight and supplements. Of the two, sunlight is your body’s most natural and efficient source, but getting it right involves more than simply spending time outdoors. Here’s how to optimize your sun exposure safely and effectively:
• How much sun do you need? Try to get direct sunlight on your bare skin daily. Use the “sunburn test” as a guide — stay in the sun just until your skin begins to turn slightly pink, then stop. Any redness at all is a signal to get out of direct sun, so avoid getting a sunburn — that’s a sign of damage, not benefit.
• Avoid seed oils before peak sun exposure — Vegetable oils are loaded with polyunsaturated fats like linoleic acid (LA), which accumulate on your skin and are extremely prone to oxidation. When exposed to sunlight, they trigger inflammation and DNA damage, putting you at risk of sunburn and skin damage.
Hence, if your diet is rich in LA, avoid direct sunlight during peak hours (10 a.m. to 4 p.m.) until you’ve reduced LA intake for at least six months. This gives your body time to flush out some of the stored LA, lowering your risk of sun-induced skin damage.
• Your body has a built-in shutoff switch — It stops making vitamin D once you’ve made enough. However, if you have darker skin, you’ll need longer sun exposure to generate the same amount of vitamin D as someone with lighter skin due to melanin’s UV-blocking effect.
• How to protect your skin while detoxing LA — If you need to spend time under the sun but haven’t completely removed LA from your body yet, here are some protective strategies I recommend:
◦Take 12 milligrams of astaxanthin daily to enhance your skin’s UV resistance.
◦Apply topical niacinamide (vitamin B3) cream before sun exposure to protect against UV-induced DNA damage.
◦Take a baby aspirin 30 to 60 minutes before sun exposure to help prevent LA conversion to harmful oxidized linoleic acid metabolites (OXLAMs).
To explore the full-body benefits of sun exposure beyond vitamin D, read “Beyond Vitamin D Production — How Sensible Sun Exposure Supports Overall Health.”
How to Supplement Vitamin D Properly
While nearly everyone would benefit from vitamin D3 supplementation, guessing your ideal dose is a mistake. The only reliable way to know how much you need is to test your blood level first and then tailor your approach based on the results.
• Don’t rely on one-size-fits-all dosing — Your optimal intake depends on multiple personal factors, including your baseline vitamin D status, body weight, skin tone, sun exposure, diet, and how much LA is stored in your tissues. What matters most isn’t the dose on the label — it’s your blood level. That’s what drives real health outcomes.
• The optimal range is higher than you’ve been told — Most guidelines set the sufficiency cutoff at around 40 ng/mL (or 100 nmol/L in Europe), but that’s just the baseline to avoid clinical deficiency. Vibra Hospital, for example, used 50 ng/mL as its therapeutic target. However, even that threshold falls short of what I recommend.
For robust immune support, chronic disease prevention, and whole-body resilience, 60 to 80 ng/mL (150 to 200 nmol/L) is the range to aim for. That’s where the real protective benefits begin — not just adequacy, but optimization.
I’ve laid out all the details in my comprehensive vitamin D report, which explains the mechanisms behind vitamin D’s effects and how to achieve optimal levels safely. Below is a brief summary of the key steps:
1. Start with a blood test — Once you know your blood level, you can determine how much vitamin D you need to raise or maintain it.
2. Calculate your personal dose — Use GrassrootsHealth’s Vitamin D*calculator to estimate how much vitamin D you need to reach your target range. If you prefer to estimate sun-derived vitamin D, the DMinder app27 helps track how much you’re likely to produce based on your location, time outdoors, skin type, and other variables. To convert U.S. units to European, multiply ng/mL by 2.5.
3. Always take vitamin D3 with fat — Vitamin D is fat-soluble. For best absorption, take it with a meal that includes healthy fat, such as grass fed butter, ghee, pasture-raised egg yolks, or tallow.
4. Retest every three to six months — Once you begin supplementation or increase sun exposure, test again after three to six months. This gives you time to see how your level responds and whether any adjustments are needed.
5. Don’t skip magnesium and K2 — If you’re supplementing with vitamin D, you also need to take magnesium and vitamin K2. Data from nearly 3,000 people show that those not taking magnesium and K2 require 244% more vitamin D to achieve the same blood level.28
These cofactors help regulate calcium metabolism, reduce the risk of calcification, and improve how your body processes vitamin D, making your supplementation more efficient and safer. To keep these nutrients in proper balance, take around 180 micrograms (mcg) of vitamin K2, ideally in the MK-7 form, along with 400 mg of magnesium, for every 5,000 IUs of vitamin D3 you take.
Frequently Asked Questions (FAQs) About Vitamin D
Q: What are the main health benefits of vitamin D?
A: Vitamin D helps your body absorb calcium, which is essential for building and maintaining strong bones. It also supports your immune system, reduces inflammation, and regulates blood sugar. Moreover, vitamin D protects cognitive function, helps keep your arteries flexible by managing calcium, supports hormone balance, and strengthens the gut lining.
Q: How common is vitamin D deficiency in hospitalized patients?
A: Data from Vibra Hospital showed that 44% of patients had levels below 20 ng/mL and 12% fell below 10 ng/mL, with some even having undetectable levels. Long indoor stays, lack of sunlight, and chronic illness all contribute to this deficiency.
Q: How does vitamin D help hospital patients recover faster?
A: Vitamin D regulates immune function, reduces inflammation, and supports tissue repair. At Vibra Hospital, patients given individualized vitamin D protocols had faster wound healing, fewer infections, and even neurological improvements. Some long-term patients who arrived unresponsive regained the ability to walk, speak, and return to daily life after reaching therapeutic vitamin D levels.
Q: What’s the best way to raise vitamin D levels naturally?
A: Daily sun exposure is the most natural source. Aim to expose your bare skin just until it starts to turn slightly pink, not red or burned. However, if you live in northern climates or have limited access to the sun, vitamin D3 supplements are a safe, affordable alternative. Just be sure to test and dose appropriately.
Q: How often should I test my vitamin D levels?
A: Test initially to find your baseline, then retest every three to six months after making changes. This helps you fine-tune your dose and monitor progress, especially if you’re supplementing or increasing sun exposure.
