Person shooting dart at targetVitamin D3 is a controversial supplement when it comes to knowing how much to take. Supplements are available in 400 IU to 5,000 IU amounts and even the experts have conflicting recommendations, adding to the confusion for consumers who wish to supplement.

So how do you figure it out?

A 2017 published Canadian study specifically looked at the factors which influenced D3 levels based on individual needs. They came up with some interesting conclusions. Data was collected from 3,882 participants with follow ups at 6 to 18 months.

D3 blood levels were obtained to determine starting D3 doses. Only about 34% tested "normal" D3 levels of 40 ng/ml or higher, despite over half the participants supplementing vitamin D3 prior to the study.

The average age was 60 years old, with 35.5% at a normal body mass index (BMI), 37% overweight, and 27.5% obese. Baseline supplementation dosages during the study period ranged from 1,000 to 15,000 IU/day.

At study end, the researchers determined that 3 factors influenced the subject's ability to achieve an adequate D3 blood level of 40 ng/ml. The 3 factors were: 1) the subject's D3 level at the beginning of the study, 2) the amount of vitamin D3 given and 3) the subject's BMI.

Subjects who were vitamin D deficient saw the greatest gains in their D3 levels after supplementation. However, "BMI was found to be the most significant factor for the vitamin D dose-response," researchers said. "The response to a given dose of vitamin D3 has been found to be 2–3 times less in overweight and obese individuals in comparison with individuals with a normal BMI." In other words, the overweight and obese subjects needed to supplement significantly more vitamin D3 to achieve the 40 ng/ml level. Specifically, "vitamin D3 intakes of at least 6,000 IU/day were required for those with a normal BMI … or 7,000 IU/d and 8,000 IU/d for overweight and obese, respectively." The researchers also looked at the safety of D3 (another controversial side of D3) and confirmed doses up to 15,000 IU a day to be safe. Source: Dermatoendocrinol 4/17.]

Many health experts recommend a minimum of 2,000 IU of Vitamin D3 daily. The Vitamin D3 Council recommends 5,000 IU daily.

Before you dose. Get a D3 blood test (25-hydroxy vitamin D) to find out your present D3 level. While a D3 level of 30 ng/ml is considered "normal", the study researchers state 40 ng/ml to be more adequate. You may need more D3 if:

  • You have fibromyalgia or chronic pain. Mark Pellegrino, M.D. recommends his patients have at least a 50 ng/ml serum level to help with pain control and he has seen more than 25,000 fibromyalgia patients.
  • You have osteopenia or osteoporosis, your level may be more in the 75-100 ng/ml range to build bones (D3 gets calcium into the bone).
  • You are overweight or obese as the study suggests 7,000-8,000 IU/day.
  • You have GI tract absorption issues (like celiac, Crohn's, IBD) as a recent meta-analysis states those with IBD are 64% more likely to be D-deficient.

Retest. It takes at least 3 months to change your blood level so make sure to retest in 3 month integrals. If you are still low, increase your dose per week and retest in 3 months again. Make sure to work with your health care provider.

HEALTH TAKE-AWAY. Be a part of your health care team and know your needs by educating yourself with reads from the TyH Online Health Library. Supplement your D3 need accordingly. TyH has 3 strengths of Vitamin D3 to help you supplement wisely.

Read More in the TyH Online Health Library

Vitamin D3 available at TyH

©TyH Publications (M. Squires). For informational purposes only.