What’s the deal with Vitamin D?

Some time ago, one of my patients came in for a checkup. Several years before, her 25-Hydroxy vitamin D level had been 13 ng/ml, which the lab had noted to be “insufficient.” She was then given ergocalciferol 50000 unit caps twice a week for 8 weeks. Her level was rechecked and had gone up to 43. Her most recent level was 22, which the lab noted to be “sufficient.”

When I saw her, she was intermittently taking cholecalciferol (vitamin D3), 25 mcg (1000 units) daily. I advised her that the evidence base surrounding vitamin D was limited, and while we could recheck a level or consult with endocrinology, I wasn’t convinced that supplementation was needed.

Later that evening, I took some time to review the literature regarding vitamin D. The bottom line – while severe vitamin D deficiency can lead to bone problems, there is controversy regarding vitamin D supplementation.

Optimal vitamin D concentration for skeletal health and extraskeletal health has not been rigorously established. Experts favor a level of 20-40 ng/ml, but I don’t think there is solid outcome data underlying that.

Certainly, vitamin D deficiency can be an issue, if there is low intake or reduced sun exposure. If the level is very low and prolonged, patients can get demineralization of their bones, which puts them at risk for fractures. For normal adults, the goal is to have an adequate intake, 600-800 IU (15-20 micrograms) of vitamin D daily.

Certainly there are nuances to this, and vitamin supplementation is a huge industry ($$). In addition, scientific research is ongoing. When I searched for “vitamin D deficiency” on pubmed I found >35,000 papers.

Any vitamin D experts out there care to weigh in?

Get some sun. Hard to do in winter.

12 thoughts on “What’s the deal with Vitamin D?

  1. .” For *normal adults*, the goal is to have an adequate intake, 600-800 IU (15-20 micrograms) of vitamin D daily.” Are older people “normal adults.?” I was told and also read many places that older people need more. A few years ago my doctor in Kentucky tested me and it was changed from 400 IU to 1000, which I take daily.

    On Thu, Dec 9, 2021 at 6:17 AM Philip Albert Lederer M.D. wrote:

    > Philip Lederer MD posted: ” Some time ago, one of my patients came in for > a checkup. Several years before, her 25-Hydroxy vitamin D level had been 13 > ng/ml, which the lab had noted to be “insufficient.” She was then given > ergocalciferol 50000 unit caps twice a week for 8 weeks. Her” >

  2. The amount of vitamin D required to effectively treat vitamin D deficiency depends, in part, upon the baseline level of serum 25(OH)D and also upon an individual’s vitamin D absorptive capacity, capacity to convert vitamin D to 25(OH)D in the liver, and, to some extent, unknown genetic determinants.

  3. For individuals with serum vitamin D levels of 12 to 20 ng/mL, usually the initial supplementation is with 800 to 1000 international units (20 to 25 micrograms).

    A repeat serum 25(OH)D level should be obtained after approximately three months of therapy to assure obtaining the goal serum 25(OH)D level.

  4. Patients being treated specifically for serum 25(OH)D <20 ng/mL (50 nmol/L) require a repeat 25(OH)D measurement approximately three to four months after initiating therapy. The dose of vitamin D may require further adjustment and additional measurements of 25(OH)D.

  5. American Geriatrics Society (AGS) and the National Osteoporosis Foundation (NOF) recommend a slightly higher dose of vitamin D supplementation (at least 1000 international units [25 micrograms], and 800 to 1000 international units daily, respectively) to older adults (≥65 years) to reduce the risk of fractures and falls

  6. Mineralization abnormalities occur as a consequence of inadequate calcium, phosphate, and/or alkaline phosphatase levels, or in the presence of abnormal bone matrix or direct inhibition of the mineralization process.

  7. Several different disorders cause osteomalacia. Severe vitamin D deficiency (25-hydroxyvitamin D <10 ng/dL [25 nmol/L]), secondary to inadequate dietary intake, lack of sun exposure, or conditions leading to malabsorption, is the most common cause of osteomalacia in adults.

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