Vitamin D Misconceptions: What You Need to Know

vitamin d

by Cora Rivard, Naturopathic Doctor (N.D.)- Seasons Natural Healthcare, LLC

The main points:

  1. Vitamin D deficiency is especially rampant in the northern half of the U.S.,  causing a myriad of symptoms and raising risk for serious chronic disease.
  2. Vitamin D levels are not assessed often enough as a diagnostic tool, and many doctors do not do enough to raise awareness of it to help their patients.
  3. As a result, many people are not aware that a wide array of health problems can be caused or aggravated by deficiency.
  4. Most people do not know how to correctly supplement it, resulting in either suboptimal levels, or adverse effects from toxicity.

In my naturopathic practice, I regularly see women who are pregnant and/or breastfeeding who want to know how to best support the healthy development of their babies. There are concerns about childhood allergies. Many patients are interested in attaining peak wellness while preventing cancer and diabetes. I see a lot of patients with concerns about fatigue, weight, mood, sleep, weakness, statin-induced myopathy, chronic pain, fibromyalgia, infections and immune function- to name a few. Every patient, of course, benefits from a thorough work up to help figure out their diagnoses, specific risks and aggravating factors. One commonly overlooked factor which can sabotage anyone’s wellness, and cause or greatly aggravate all of the previously mentioned health issues, is vitamin D deficiency. It is a global epidemic.

Why is it usually overlooked? One reason is that education about nutrition and the role of nutrients is often not given enough time or consideration in conventional medical training, even though the bulk of evidence about vitamin D comes from medical research facilities. Second, even if they are aware, primary care practitioners may not have the time to discuss it in a short visit. Medical focus to this nutrient is usually limited to prevention of osteoporosis in the elderly (a recent study from China just disputed this generally accepted line of evidence), and rickets in children. While these areas are important, they don’t cover the whole story about why vitamin D is so important to functions of many of the body’s systems, throughout the life cycle.

Vitamin D’s origin story: UVB light from the sun reacts with a compound called 7-dehydrocholesterol in the epidermis of the skin to stimulate the first step in the production and metabolism of a vitamin D, which is biologically inactive until it undergoes 2 hydroxylation reactions to become active. It is hydroxylated first in the liver to form 25-hydroxyvitamin D, or (25[OH]D), and then by the kidneys to form 1,25-dihydroxyvitamin D, the biologically active form which functions as a hormone in the body, and there are receptors for the hormone in many body tissues. This is the primary route, though small, naturally occurring amounts can also be naturally consumed from foods such as cheese, egg yolks, cold water, fatty fish, and liver. It can also be produced by fungi as a response to irradiation, in the form of D2, and is often added to commercial foods such as dairy products, infant formula and multivitamins.

In New England, we are especially challenged by our high latitude to get enough sun exposure for adequate levels of this vitamin throughout the year. While vitamin D deficiency is common throughout the U.S. (and world), this is why it is especially common here.

So what are the misconceptions?

#1 Misconception: Testing: Doctors may not have the inclination to test vitamin D levels if they are not well-informed about its importance to many aspects of health and wellness. In my experience locally, some insurance carriers may not even cover testing for it unless there is a diagnosis of osteoporosis or a previous diagnosis of low vitamin D. So most people who are deficient and suffering from related symptoms out there have no idea they are deficient!

If your doctor doesn’t order it, and/or your insurance won’t cover it (and these tests can often range from between $120-$200 if insurance denies the claim), what can you do? You may choose to use a service such as LifeExtension, who partners with Labcorp for self directed tests. This one costs around $47. There are also panels that include it as part of a wellness screen. (I don’t have any relationships with, or receive any financial perks from LifeExtension, but I have found them helpful for patients wishing to pay cash for reasonably priced testing services for wellness, when insurance is not an option.)

#2 Misconception: The more the better! On the opposing side, there are practitioners that get very excited about vitamin D and recommend excessive doses; it cures everything! While not a “cure-all,”  it can offer dramatically positive results for those who have been deficient. Caution is always warranted because it is a fat soluble hormone that accumulates in fat cells. And consider this: synthetic cholecalciferol (D3) is registered and used as a rodenticide! Toxicity causes a quick rise in serum calcium levels (hypercalcemia), cardiac abnormalities, hypertension, renal failure, and calcification of the of the walls of blood vessels.

Controversy still remains about which vitamin D form is better to measure in lab tests, and what the results mean. For example, a typical “normal range” of 25-Hydroxyvitamin D (25OHD) is 20-100ng/mL by lab standards. My experience is that patients with levels under 30 are often symptomatic for deficiency,  and serum levels over 55-60 are just not necessary, and might even be harmful. A study shows that Hawaiian surfers spending at least 15 hours per week in the sun have ranges including the 50’s to around 70 at the highest ends. And this is where it gets interesting: UVB exposure stimulates vitamin D production only up to certain point, and then it begins to degrade vitamin D in the skin. So the body’s levels are balanced when vitamin D is gained from sun exposure. But oral vitamin D is different, there’s not the same natural correction from supplementing too much. Toxicity is therefore a concern with supplementation, but not with sunlight exposure. Research shows that taking vitamin D in bolus form (or intermittent, higher dosages) actually causes more falls and fractures in the elderly. From serum vitamin D levels from supplementation, the line between preventing fractures, and causing fractures, may be a slim window and located closer to the lower end of the “normal” testing ranges.

The 25(OH)D level achieved by oral dose of vitamin D supplementation varies widely by individual. It is likely affected by calcium intake, race, age, body fat, and individual genetic factors. Genetic variation from polymorphisms of certain genes in the vitamin D metabolic pathway can also cause wide individual differences.

What about tanning beds? While this does stimulate vitamin D production, I believe it is not worth the skin damage and significantly increased risk of cancer associated with tanning bed use.

When I review a patient’s nutritional supplements, I often find extra vitamin D included in many products: shakes, multivitamins, energy supplements, etc. It is important to look at all ingredient labels and to be aware of how much you are getting in total. Toxicity from vitamin D causes too much calcium to be released into the blood (hypercalcemia), which can cause bone demineralization, reduced appetite, nausea and vomiting, weakness, cardiac arrhythmias, increased urination and kidney problems.

Misconception #3- Take it Anytime! Since vitamin D is a fat soluble hormone, it should be taken with a food/meal that contains some fat, for best absorption. It is also stored in the fat, which might reflect why many people who are overweight can have sufficient stores of vitamin D, but low circulating levels. Alternatively, if an overweight person is on a weight loss plan, their levels may may rise significantly as vitamin D is released, especially from rapid or significant weight loss- so extra caution is needed here, especially if there are issues of cardiac arrhythmia.

So how much is enough, without going overboard? I often recommend 400-600IU’s daily for young children, 600-800IU’s daily for older children, and 1,000IU-2,000IU’s for teens and adults as a general guideline. I adjust up or down depending on specific needs or risk factors, and individual responses according to testing and symptom resolution. People with malabsorption issues, or those taking medications like certain corticosteroids, heartburn medications, or anti-epileptic drugs, often have higher needs for vitamin D. I usually recommend taking a break from vitamin D supplements from late spring through the summer months for most people.

What brands should you take? While I can’t ethically put that in a post, I often recommend products that are in an oil emulsion form for best absorption. Dropper bottle products are also very cost effective since they hold so many servings.

I love feedback! Please feel free to write in a comment, and let me know what you think of this article. And, please share with your social circles.

Cora Rivard is a licensed naturopathic doctor and owner of Seasons Natural Healthcare, LLC in southern NH. She has been a healthcare practitioner, business owner, writer and advocate for family health and wellness since 2006. In her spare time she enjoys leading a school Destination Imagination team, cooking, hiking with her family, learning to play the violin, playing doubles beach volleyball with her husband, and cross country skiing. Website: Seasons Natural Healthcare, LLC. She is currently accepting new patients.



  1. I loved this article. My moms doc recently put her on 25k units per day. This may be too much for her since she likely gets some from her diet and sun exposure. Also she is likely more susceptible to bone issues and or falling.
    Do you do a blood panel on intakes?
    I may schedule her in for an appt.

    • You should discuss those concerns with her doctor, it does appear that the larger dosages increase, not decrease, risk of falls and fractures within several months of initiating. I can do testing, including for vitamin D

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