The intent of our new blog post section is to provide the public with timely information on vitamin D. This may be related to new vitamin D research, issues or programs. Our goal is to provide you with the best answers and information from the top vitamin D scientists. This will be accomplished in part through interviews and also guest blog posts.
Does the Health Canada Adult Vitamin D Recommendation Make Sense?
By Perry Holman, Executive Director, Vitamin D Society
For our first blog post I am going to review the current Health Canada and Institute of Medicine (IOM) recommendations for vitamin D. Do they make sense? I have always been puzzled by the recommendations from Health Canada that small baby infants receive 400 IU/d and large adults receive just 600 IU/d. That just doesn’t make sense to me. Does it to you? Here is what is provided on the Health Canada website for vitamin D:
Recommended Dietary Allowance (RDA) per day:
Infants 0-6 months – 400 IU
Infants 7-12 months – 400 IU
Children 1-3 years – 600 IU
Children 4-8 years – 600 IU
Children & Adults 9-70 years – 600 IU
Adults >70 years – 800 IU
Let’s look into this a little further. Health Canada is recommending a dose of 400 IU/d for an infant baby. How heavy is an infant baby? When a new infant is brought home from the hospital many are below 10 pounds. This is when the mother starts providing a vitamin D supplement of 400 IU/d if she is breast feeding. If the baby is on infant formula (breastmilk substitute) this amount of vitamin D is provided in the formula. So for a 10 pound infant receiving 400 IU/d of vitamin D supplement that works out to 40 IU per pound (or 88 IU per kilogram). Research studies have found that infants taking a dose of 400 IU/d reach a vitamin D 25(OH)D blood level of > 100 nmol/L. 1
Moving on to adults, the Health Canada recommendation for vitamin D is 600 IU/d. So if you are a 200 pound man that would be 3 IU per pound (or 7 IU per kilogram). Does that seem correct to you? That a baby infant should receive a dose of 40 IU/pound and an adult man 3 IU/pound? Would a doctor prescribe an adult a baby dose of a drug? Or a baby an adult dose? An adult will not achieve the same vitamin D 25(OH)D blood levels as an infant based on these dosages. It just does not make sense.
Clearly Health Canada and the Institute of Medicine would not recommend or advise an infant dose that could possibly provide harm or a health risk. So, 400 IU/d or 40 IU per pound, is a safe and healthy dose for an infant. Using the same logic than the safe dose of 40 IU per pound for an adult man weighing 200 pound would be 8,000 IU/d.
The key to vitamin D is your 25(OH)D blood level. That is how you know what level of vitamin D you have in your blood. The Vitamin D Society follow the recommendations endorsed by 48 vitamin D doctors, scientists and researchers who through GrassrootsHealth published a Scientists Call to D*action which recommends everyone, all ages, all skin types, all weights, achieve an optimal vitamin D level of between 100-150 nmol/L.
So to answer the question in our heading, the vitamin D dose of 600 IU for adults does not make sense. Using the same dose per pound as recommended by Health Canada and the IOM for infants the adult dose should be at least 10X higher and in the range of 4,000 – 8,000 IU/d based on weight.
1. Wagner CL, Howard C, Hulsy TC, Lawrence RA, Taylor SN, Will H, Ebeling M, Hutson J and Hollis BW. Circulating 25-Hydroxyvitamin D levels in Fully Breastfed Infants on Oral Vitamin D Supplementation. Int J Endocrinol. 2010;2010:235035. doi: 10.1155/2010/235035. Epub 2009 Dec 9.