What Is the Optimal Dosage for Vitamin D3 Supplementation?

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Posted: 04 Aug 2014 08:00 AM PDT

Vitamin D is a hot topic in the news these days, and it's also one of the most controversial subjects in medical research. The main debate concerns the optimal dosage of vitamin D3, a natural "nutrient" synthesized by the body in response to sunlight exposure. Current governmental guidelines may be advocating for less-than-ideal vitamin D levels by giving a generalized recommendation for supplementation. It really is up to consumers to do the research to see how much vitamin D is really necessary.

Sources of Vitamin D

The most natural method of getting an optimal intake of Vitamin D is through good ol' sunshine. While sunshine may be optimal, many are precluded from getting enough to contribute meaningfully or sufficiently to their daily intake of Vitamin D. Those living farther from the equator or those who stay inside all day — especially in the autumn and winter months — will often experience a dramatic drop in vitamin D status. Glass windows, while transmitting sunlight indoors, act as a barrier to UVB rays, the most beneficial rays for vitamin D synthesis. ^[1] ^[2] This is why supplementation is so important for most people.

What is the Optimal Dosage?

When it comes to setting a clear and uniform value for vitamin D dosage, everyone has their own opinion. The Food and Nutrition Board (FNB) established the now common 400 IU (international units) per day of Vitamin D, and the Institute of Medicine has set the recommended daily intake at 600 IU per day. These recommendations are said to raise blood levels of vitamin D to 20 ng/mL and 30 ng/mL, respectively.

Experts in the field of vitamin D will often recommend an average of 1,000 to 1,500 IU per day, depending on the vitamin status of the patient. ^[3] This will often generate, on average, a 60 ng/mL blood level. Even then, this may not be an appropriate intake. An article in Osteoporosis International indicates that 2,000 to 3,000 IUs should be taken every day, especially by the elderly. ^[4] Individuals with massive vitamin D deficiency may require upwards to 10,000 IU per day. Fortunately, toxicity for vitamin D at these levels remains absent from clinical observation. ^[5]

The reality is that most people are insufficient in this necessary nutrient, an issue that is unquestionably having a large impact on the health of society. Americans are falling ill with every manner of disease at an ever-increasing rate, and many researchers believe these diseases — cancer and heart disease being the most common — are influenced to some degree by vitamin D status.

Optimal Blood Levels of Vitamin D

With all the research being established in relation to vitamin D and human health, it's a wonder why so many health organizations continue to disagree on the correct amount of D3 that should be circulating in the blood. On average, most organizations believe a level between 40-80 ng/mL is suitable for most individuals, with the average (60 ng/mL) being optimal. There is no one-size-fits-all dosage for Vitamin D intake, making testing a crucial determinant of supplementation dosage.

Testing for Vitamin D

With all the research being established in relation to vitamin D and human health, it's a wonder why so many health organizations continue to disagree on the correct blood levels of vitamin D. On average, most organizations believe a range between 40-80 ng/mL of vitamin D is best for most individuals, with the average (60 ng/mL) being optimal. ^[6]

So how can we know what our bodily status of Vitamin D is at any given moment? Blood measurements. ^[7] This is the only sure method to assessing one’s current Vitamin D levels that can then clue us in, with certainty, of what our nutrient status is and how to get our levels to a more optimal range. The relevant blood marker to check for is called 25(OH)D, short for 25 hydroxyvitamin-D. Measures range from 0 to 100 ng/mL, with many patients aiming for a number somewhere in the high middle.

Bottom Line

Fortunately, as Vitamin D awareness and importance has grown, getting your blood tested is becoming a far more common request at the doctor’s office and most insurance agencies cover this simple test. Based on the research, investigations, and extensive experience of the aforementioned experts in the field, a safe, somewhat general recommendation is to consume between 2,000 IU to 4,000 IU/day (3,000 IU/day avg.) of Vitamin D3 (cholecalciferol). To ensure optimal supplementation, ask your doctor about getting tested for 25(OH)D.

-Dr. Edward F. Group III, DC, ND, DACBN, DCBCN, DABFM