Dr. Vliet’s Health Tip: The Vitamin D Lie: “Normal” Levels Are Dangerously Low – Aim for Above 70 or Risk Your Health

© by Elizabeth Lee Vliet MD and Kathy Kresnik

Vitamin D is probably the most important overlooked life saver and SHIELD in our health and resilience armamentarium! Ignoring its importance, and failing to check blood levels regularly, means you are playing Russian Roulette with your health.  Both my medical experience over the last 40 years and current research studies confirm that for far too long, conventional “wisdom” has set target vitamin D levels far too low to achieve all the critical functions in the body that this wonder hormone provides.  Yes, that’s right.  I said “hormone.” “Vitamin” D is actually a hormone, not a vitamin.  I explained that in my earlier article on Vitamin D.

There are serious myths about the level of vitamin D you actually need.  Tragically, doctors and institutional guidelines are still telling patients that Vitamin D levels between 20-30 ng/mL are “normal.”  Even my own patients, for whom I am trying to get Vitamin D into optimal ranges, have primary care docs telling them they are “taking too much” or their level is fine at 30!  It is very frustrating for me.

Big Medicine seems unwilling to admit that current research has shown for the last 25 years or more that Vitamin D stores need to be above 60 ng/mL and ideally in the 70-90 ng/mL range—measured as 25 (OH) vitamin D in the blood.  Globally, roughly half of people have suboptimal vitamin D by common bone‑health thresholds, and about 1 in 6 have deficient levels.

Keep in mind this key point: “normal” on a lab range is NOT THE SAME as optimal for your body needs!  Vitamin D deficiency is often the silent killer hiding behind what patients were told is a “normal” lab result.  Insufficient, or deficient, vitamin D stores are simply too critical to ignore.  So today, I teach you what you need to know about why higher levels are critical to your health, how to get tested, and how to improve your vitamin D stores.

So How Did We Get Here? Why Vitamin D Intake Recommendations Miss the Mark

Many physicians focusing on health as more than just absence of disease have long recognized the crucial role Vitamin D plays in just about every system in the body.  Current national guidelines recommend daily intakes for Vitamin D that are far too low for optimal health based on the most current studies of correlation between Vitamin D levels and various medical disorders. The official RDA of 600–800 IU per day, set by the Institute of Medicine in 2011, was meant to keep almost everyone’s vitamin D levels above 20 ng/mL. However, later research found that this dose only helps the average person reach a minimum level, which means most people are way below the what we now know to be the optimal threshold of at least 60 ng/mL.

This original recommendation also only focused on bone health (and still is too low for even that!), not on vitamin D levels needed for other organ systems to function optimally.  Scientists re-examined the data and discovered that a much higher dose—often several thousand IU per day—is needed to ensure adequate vitamin D levels for nearly everyone.

Despite this, major health authorities have not raised their recommendations, either because of inertia, or because so many medical groups have not taken into account the newer research showing higher levels are needed for most conditions, or because there is more money to be made for Big Pharma pushing Rx medicines to treat  diabetes, heart disease, cancer, osteoporosis and depression than there is in testing vitamin D and recommending over the counter supplements. and keep pushing outdated lab ranges.

If you rely strictly on the low RDA of 600-800 IU per day from food and a multivitamin, and do not take any vitamin D supplements at all, you may not even reach minimal levels, much less optimal vitamin D levels. That’s especially true for people with a higher BMI, or who spend little time outdoors, or live at northern latitudes.

For better health, consider current vitamin D recommendations as a only as a minimum starting point and adjust your dose based on lab tests and individual needs—often up to 5,000 IU or even more daily—while keeping blood levels within safe limits unless your doctor advises otherwise.

Serum vitamin D stores are measured by the blood test 25 (OH) vitamin D, commonly expressed in ng/mL.  Do not be confused with levels expressed in nmol/L, as these will be higher numbers but can be misleading because the unit is not the same we are typically using.  Here are some common ranges and what they mean:

• Severe deficiency: <10 ng/mL, depending on the lab.  Some use less than 20.
• Deficiency: < 20 ng/mL (NIH/FNB)
• Insufficiency: ~21–30 ng/mL (some doctors still accept this as “normal”)
• Generally adequate/normal: above 50 ng/mL (current studies)
• Optimal: 70-90 ng/mL (many current experts, based on recent data)
• Higher than needed, possible adverse effects: >100 ng/mL
• Toxicity: >150 ng/mL (some labs use lower level for defining toxicity)

The preferred test is 25‑hydroxyvitamin D [25(OH)D] because it reflects the body stores.  1,25‑dihydroxyvitamin D is not used for checking vitamin D stores because it measures what is circulating in the blood at a given time, and is affected by many factors.  The 1,25 dihydroxy vitamin D test is usually used just for specific settings (advanced kidney disease, granulomatous disease, certain hypercalcemia evaluations)

Most primary care doctors still don’t do routine screening for vitamin D testing, so you may need to specifically request this test. But with the lifestyle and work environments shifting towards much more indoor activities and less time outdoors for adequate sun exposure, along with fear of skin cancer from too much sunshine, we are seeing increasing numbers of people with vitamin D deficiencies.  I recommend that people have a vitamin D test at least once a year.  Then, after starting or changing vitamin D supplements, repeat 25(OH) D blood test no sooner than about 12 weeks, allowing a new steady state to be reached.

The Bottom Line:

• Low vitamin D levels are common because Big Medicine recommendations and most doctors haven’t kept up with new science showing levels higher than 50-60  ng/mL are crucial.
• Many people need much more than 600–800 IU/day to avoid both vitamin D deficiency and Vitamin D insufficiency.
• Sun exposure, body weight, and individual metabolism affect how much vitamin D you need, and every person is different – blood tests help decide what you need.
• It is imperative to talk to your doctor and request a current blood test for the level of vitamin stores, 25 (OH) vitamin D.  Then adjust your supplement dose to reach optimal level for health.
• You cannot aim for just a minimum Vitamin D level.  That will lead to subtle ongoing damage to your bone and overall health. Remember, diabetes, heart disease, bone loss, and even cancers are all increased in people with low vitamin D stores.

Low Vitamin D and the Silent Calcium Crisis: Low Levels Steal Bone Health

Vitamin D and calcium are also closely linked in maintaining bone health and proper functioning of many bodily processes including muscle function, and overall metabolic balance. Many people have a vague understanding that vitamin D helps with calcium absorption in a way that plays a role in healthy bone. But most people, and even many doctors, don’t understand the details of this relationship—and what happens when vitamin D is lower than what the body needs.  So, for today’s Health Tip, I also explain how vitamin D deficiency impacts calcium levels, why serum calcium is often preserved until deficiency is severe, and the adverse health effects on bone and other organs that can occur in these situations of low vitamin D causing abnormal calcium metabolism.

I described the Vitamin D ranges above. Normal total serum calcium is about 8.5–10.2 mg/dL. Serum calcium has a narrow range and is tightly controlled by your body when the parathyroid glands are operating normally.  But when vitamin D levels are suboptimal, calcium metabolism is disrupted.

How Does Vitamin D Affect Calcium?

Vitamin D plays an essential role in helping the intestines absorb calcium and phosphate from the foods we eat. Without enough vitamin D, your gut cannot efficiently absorb these minerals, even if your dietary intake is adequate. This is critical point: over time, a lack of vitamin D can gradually deplete your body’s calcium stores, even if you are consuming enough calcium in your diet.

This occurs because your body has built-in mechanisms to keep the calcium in your blood (serum calcium) within a normal range for as long as possible. When vitamin D is low, your intestines absorb less calcium, but your body compensates through the action of parathyroid hormone (PTH). A small drop in blood calcium triggers the release of PTH, which works to maintain serum calcium by increasing calcium reabsorption in the kidneys and releasing calcium from your bones. As a result, serum calcium typically stays within normal limits during mild or early vitamin D deficiency, but the rest of the body is being slowly damaged, and silently losing bone.

Signs of Parathyroid Compensation for Low Vitamin D

In mild or early cases of vitamin D insufficiency/deficiency, blood tests may show normal serum calcium but elevated or high-normal PTH. Other changes can include low-normal phosphate and higher levels of alkaline phosphatase (ALP), an enzyme linked to bone turnover. These laboratory findings can indicate that the body is working harder to maintain calcium balance, and may be losing bone, even if there are no symptoms yet.

In prolonged or severe vitamin D deficiency the body’s compensatory mechanisms may no longer be enough. At this stage, the intestines cannot absorb enough calcium to meet the body’s needs, even with high PTH levels, and true hypocalcemia (low blood calcium) can develop. This condition can lead to symptoms such as muscle cramps, tingling, and, in severe cases, cardiac arrythmias, heart attacks, or even seizures.

Some individuals with low vitamin D cannot mount a proper PTH response due to underlying medical conditions, such as certain types of parathyroid disease or kidney disorders. In these cases, serum calcium may drop sooner and more noticeably, as the body cannot compensate for the lack of vitamin D and may present with symptoms of hypocalcemia despite only moderate vitamin D deficiency.  All of these situations are serious, and potentially life-threatening if not addressed and corrected.

WARNING – BE PROACTIVE! If you have risk factors for vitamin D deficiency—such as limited sun exposure, darker skin, or certain dietary restrictions—it is especially important talk to your doctor about monitoring lab levels:  25-hydroxyvitamin D (25(OH)D), PTH, calcium (both total and ideally ionized), phosphate, and ALP together. This combination of markers gives a more comprehensive view of how vitamin D status is influencing calcium metabolism and ultimately whether or not you are losing bone.

The Problem Is Significant and Needs to be Taken Seriously

Earlier in this health tip I said that roughly half of people worldwide have suboptimal vitamin D by common bone‑health thresholds, and about 1 in 6 have deficient levels. And this is if you follow the defined “suboptimal” level around 20 ng/mL. If you use a more generous “insufficiency” cutoff like 30 ng/mL—still way too low based on my review of current research—then 75% of people worldwide are below that level. No wonder COVID illness caused such damage. But Big Medicine and Big Government did not tell the public that simply greatly increasing vitamin D intake (and sun exposure) could have reduced the COVID death toll dramatically.

Today’s research shows that people with the lowest risk of serious conditions (diabetes, heart disease, cancer, osteoporosis) have Vitamin D levels in the top quartile of the reference range: levels of above 60 ng/mL and ideally in the 70-90 ng/mL range.  I tell my patients that optimal vitamin D means a level between 80-90 ng/mL.  That’s my goal personally for me as well.

But in the United States we find much more dismal and alarming stats:

• NHANES 2011–2014 data show about 5% of US residents ≥1 year have 25(OH)D <12 ng/mL and 18% between 12–19 ng/mL; together, ~23% are <20 ng/mL.
• Several US adult cohorts report roughly 39% with ≤20 ng/mL and about 64% with ≤30 ng/mL, depending on age, ethnicity, and assay.
• Another major review (“Vitamin D deficiency 2.0”) reports similar patterns and notes that 25(OH)D <20 ng/mL is common in 24% of the US, 37% of Canadians, and 40% of Europeans, using standardized assays.

Warning: Vitamin D Levels less than 30 ng/mL are too low for bone and overall health. You really need to be proactive on this!

Based on more current studies, Vitamin D below about 30 ng/mL is considered inadequate for bone and overall health and is linked to adverse health effects in multiple systems, not just calcium and bone. We know that chronic low vitamin D impairs calcium and phosphate absorption, driving secondary hyperparathyroidism. This leads to soft bones (osteomalacia), reduced bone mineral density, and higher fracture risk. It contributes to proximal muscle weakness and pain, poorer balance, and increased falls, especially in older adults.

But suboptimal vitamin D levels damage the entire body. Pooled RCT data suggest daily vitamin D3 supplementation produces a reduction in all‑cause mortality.  Suboptimal vitamin D is associated with higher risk of cardiovascular disease, diabetes, and some cancers.  Here are some of the broader effects on the whole body when Vitamin D is too low:

Immune and infection risk:

• Vitamin D receptors are expressed in many immune cells, and vitamin D modulates innate and adaptive immune responses.
• We saw during COVID that individuals with low vitamin D levels were more severely affected and had higher death rates.  Multiple observational studies and meta-analyses (2020–2023) consistently show that vitamin D levels above 50-60 ng/dL are associated with significantly lower risk of severe COVID-19 outcomes, including hospitalization and mortality — with some cohorts reporting near-100% protection at that threshold. (e.g., Entrenas Castillo et al., Journal of Steroid Biochemistry, 2020; meta-analyses in Nutrients and The Lancet).
• Low levels have been associated with higher rates of respiratory infections and with autoimmune conditions.

Cardiometabolic health and mortality:

• Vitamin D Deficiency and insufficiency are associated with greater risks of cardiovascular disease, type 2 diabetes, and all‑cause mortality in cohort studies.
• In older adults, having both low 25(OH)D and high hs‑CRP roughly doubles all‑cause and cardiovascular mortality risk versus people who do not have either abnormality.  That data suggests an interaction between vitamin D status and systemic inflammation.

Cancer and cell regulation:

• The vitamin D receptor (VDR) is widely expressed in non–calcium‑regulating tissues, and vitamin D signaling influences cell proliferation, differentiation, and angiogenesis.
• Low 25(OH)D is epidemiologically linked to higher incidence or poorer prognosis of several cancers, and one large trial suggested vitamin D3 may reduce progression to advanced cancer

Barriers, skin, and other tissues:

• Vitamin D and Vitamin D Receptor signaling helps maintain epithelial and endothelial barrier integrity in skin, gut, lung, and other organs, partly via tight junction proteins.
• Deficiency is associated with chronic musculoskeletal pain, fatigue, depressed mood, and slower wound healing, though these are nonspecific and may have other causes in addition to low vitamin D. Lab tests are needed to clarify the various causes.

Symptoms of low and deficient levels of vitamin D

Vitamin D deficiency typically does not cause obvious symptoms at first.  When symptoms do occur, they are usually musculoskeletal and sometimes quite nonspecific. People at risk for low vitamin D include those with limited sun exposure, darker skin, malabsorption, obesity, chronic kidney or liver disease, people taking certain medicines, such as anticonvulsants, steroids, and fat-blockers.  Symptoms also may vary based on age:

Children and infants:

• Irritability, delayed milestones, and poor growth.
• Signs of Rickets: bowed legs, widened wrists, soft skull, delayed tooth eruption.

Adolescent and Adult general symptoms:

• Diffuse bone pain or deep ache (spine, hips, ribs, legs).
• Proximal muscle weakness (difficulty climbing stairs, rising from a chair, walking distance).
• Muscle aches, cramps, twitches, or tremor. (More on this below)
• Fatigue, low energy, feeling “run down.”
• Increased falls and fractures, especially in older adults.
• Poor sleep and nonspecific malaise.
• More frequent infections or “getting sick easily,” reflecting immune effects.

Neurologic, sensory and mood symptoms:

• Tingling or “pins and needles” in hands or feet (from associated hypocalcemia in more severe cases).
• Muscle spasms or tetany in marked deficiency, sometimes with low calcium.
• Low mood, irritability, or depressive symptoms.

Low vitamin D leads to low calcium symptoms (cramps, tetany):

Severe or prolonged vitamin D deficiency can lead to true hypocalcemia, which in turn can cause cramps, paresthesia (abnormal skin sensations such as tingling, prickling, burning, or crawling), and even tetany (seizures), but this is usually a later and more severe manifestation.
As we discussed, vitamin D deficiency reduces intestinal calcium absorption, which can eventually drop ionized calcium enough to cause hypocalcemia. When ionized calcium falls below roughly 4.3 mg/dL (about 1.1 mmol/L), patients can develop the classic hypocalcemic spectrum: “pins and needles,” tingling around mouth and fingers, toes, hands and feet, muscle cramps, spasms in the hands and feet, laryngospasm, and tetany that improves with calcium plus vitamin D replacement.

Mild vs severe deficiency

• Mild–moderate deficiency often has normal serum calcium (due to secondary hyperparathyroidism) and may cause vague muscle aches or weakness rather than frank tetany.
• Cramps in people with low vitamin D can be from a mix of mechanisms: subtle hypocalcemia, direct effects of vitamin D on muscle function, and sometimes concurrent low magnesium or other factors.

ACTION STEPS: If you have recurrent cramps, tingling, or any signs suggestive of seizure, have your physician check serum calcium (total and ideally ionized), magnesium, PTH, and 25‑OH vitamin D together to clarify whether low vitamin D has progressed to clinically significant hypocalcemia.

Dietary Suggestions for Increasing Vitamin D Intake and Absorption

Diet can support vitamin D status, but even excellent intake rarely prevents the need for taking supplements, especially for people living in areas with limited sunlight or more northern latitudes. Here are practical ways to boost both intake and absorption.

Best food sources of vitamin D: Focus on foods naturally rich + fortified staples.

• Fatty fish: salmon, mackerel, herring, sardines, trout, and canned tuna.
• Fish liver oils: e.g., cod liver oil (very concentrated; watch vitamin A load).
• Egg yolks: more if hens are pasture‑raised or fed vitamin D–enriched feed.
• Beef liver and some red meats: modest amounts but nutritionally dense.
• UV‑exposed mushrooms: maitake, portobello, shiitake grown/treated under UV.
• Fortified foods: cow’s milk, many plant milks (soy, oat, almond), some yogurts, margarines, breakfast cereals, and some orange juices—check labels for “vitamin D” and IU per serving.

GUIDELINE: A single serving of fatty fish can easily provide a large fraction of the standard 600–800 IU “daily value,” while most fortified foods contribute ~80–150 IU per serving.

For example, Wild salmon ~3.5 oz: about 600–1,000 IU on average,   often providing 75–>100% of 600–800 IU in a single serving. Other fatty fish (mackerel, herring, sardines, trout) ~3 oz: typically ~200–500 IU, around 25–80% of 600–800 IU.

Strategies to Better Absorb & Utilize Vitamin D:

• Eat it with fat: Vitamin D is fat‑soluble, so include healthy fats (e.g., olive oil, avocado, nuts, whole eggs, fatty fish) in the same meal.
• Spread intake across meals: Regular exposure (fish a few times weekly, daily fortified foods) supports steadier status more than sporadic “vitamin D meals.”
• Take Vitamin D with calcium foods: This doesn’t increase D absorption, but supports bone/mineral metabolism (e.g., sardines with bones, salmon with bones, dairy or fortified plant milks, leafy greens).

Sample meals to emphasize obtaining Vitamin D from food:

• Breakfast: Omelet with 2–3 eggs plus fortified dairy milk.
• Lunch: Fortified yogurt or kefir
• Dinner: 3–4 oz salmon or mackerel; side of sautéed greens.
• Additional suggestions: 1 tsp cod liver oil or ½ to 1 cup fortified orange juice.

Factors that reduce absorption or increase Vitamin D needs:  Even with good diet, some people need more vitamin D under certain conditions or taking certain medicines. In these settings, diet alone almost never achieves and maintains target 25(OH)D levels; supplementation plus lab monitoring is typically required.

• Higher body fat percentage: Vitamin D gets taken up and held inside fat tissue, reducing how much is freely available in the blood and for other tissues. Because more of it is “parked” in adipose tissue, less circulates to be immediately bio-available to cells.  People with higher percentage of body fat commonly have lower serum 25(OH)D and often need higher doses to reach optimal blood levels.
• Malabsorption: Celiac, Inflammatory bowel disease, bariatric surgery, chronic pancreatitis, cholestatic liver disease, fatty liver disease.
• Medications: Some anticonvulsants, glucocorticoids, rifampin, and some HIV meds increase enzymatic breakdown of vitamin D and its active metabolites in the body, which means 25(OH)D is cleared faster, so serum levels drop unless intake/synthesis is higher.
• Very low‑fat diets or fat‑blocking meds: Orlistat and similar agents reduce absorption of fat‑soluble vitamins.

Strategy to Optimize Vitamin D: Diet + Outdoor Lifestyle + Quality Supplements

Targeting a blood level of 25 (OH) vitamin D in the optimal range of ABOVE 60 ng/mL ( ideally 80-90 ng/mL) means you are going to need to add a high quality D3 in olive oil supplement for two reasons: 1) most Americans do not eat enough of the Vitamin D-rich foods each day to reach these levels, and 2) most Americans are not out in the sun without sunscreen enough time each day, or at the right latitude, to achieve optimal Vitamin D levels.

It is Important to Supplement with Quality Products

I have recommended Vitamin D3 in olive oil capsules to my patients throughout my medical career.  That is why I have included TruBioD3™ in my Resilience Formula.  I have found over many years of tracking blood levels for patients using different commercial Vitamin D products that sublingual drops, hard tables/caplets, and capsules that use other types of oil (sunflower, soy, safflower, canola oil, etc) as the carrier for fat-soluble Vitamin D3 simply do not bring up the vitamin D levels adequately –so people end up wasting money, and lose time and health benefits because they think vitamin D is improving, and it actually isn’t.

You really do need to monitor the proper vitamin D blood level at least once a year to know that your Vitamin D stores are actually in the optimal range. they are getting better vitamin D!

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TruBioD3 contains vitamin D3 (cholecalciferol) with extra virgin olive oil in convenient soft gels. Vitamin D3 is the bioidentical form of vitamin D synthesized in the body from cholesterol, following activation by the UV rays in sunlight. This form is excellent for maintaining healthy levels of vitamin D stores in the body.

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