Importance of Vitamin D
Vitamin D is well known to be an important nutrient factor in achieving and maintaining good health.
Nearly every cell in the body uses vitamin D and the health benefits of vitamin D range from reducing heart disease to boosting the immune system.
At Pure North we know one of the most important things people can do to improve their overall health is to determine the daily intake required to reach and maintain their optimal vitamin D level.
A blood test to measure serum concentration of 25-hydroxy-vitamin D (25(OH)D) is the best way to determine someone’s vitamin D status and reflects the total amount of vitamin D from food, supplements and sun exposure.
A supplement can help the body get the vitamin D it requires.
Canadians can’t make vitamin D from the sun in the winter.
International experts on health recommended vitamin D levels be in the range of 100 nmol – 175 nmol/L (40 ng/ml – 70 ng/ml). To achieve these levels, people need to get adequate sun exposure, eat enough vitamin D rich food, or take supplements.
A blood test is the only way to determine a person’s current levels of vitamin D, and how much more they need to achieve and maintain good health.
“The BC population is at risk of low vitamin D levels from autumn to spring. There is no clinical utility in performing vitamin D tests on patients who are thought to be at risk for sub-optimal vitamin D levels and who would benefit from vitamin D supplementation.” – Ministry of Health – Province of British Columbia
Private services are available for people keen to understand their body’s vitamin D level and determine a specific daily intake amount of vitamin D to achieve and maintain an optimal level.
In the absence of a blood test there are resources available to estimate a daily-recommended intake of vitamin D required to achieve an optimal blood serum level.
As a general rule 35-40 IU of vitamin D is required, per pound of weight, for a person to achieve an optimal vitamin D range.
It is important to remember factors such as height, weight, BMI and skin tone are all things that impact vitamin D supplementation requirements and therefore a blood test is recommended as the most accurate way to determine a recommended daily intake.
A number of calculators have been developed to help provide a general guideline of the amount of vitamin D absorbed through exposure to the sun.
This is one of the most robust calculators and has been used to create the following chart:
Canada’s location creates a vitamin D ‘Feast-or-Famine’ environment.
When exposed to the summer sun the body is a vitamin D-making machine, creating upwards of 20,000 IU in less than 30 minutes.
Yet, with Canada’s northern latitude and proximity to the sun, Canadians aren’t able to generate vitamin D in the winter months (late October through early March). The angle of the sun in the winter months means not matter how many sunny days there are the vitamin D-soaked UVB rays aren’t powerful enough for people to make vitamin D from the sun’s rays.
“Within 10 to 20 minutes, without wearing sunscreen, people make between 10,000 and 20,000 IU (of vitamin D). But because of widespread sunscreen use, total sun avoidance, and our increasingly indoor lifestyles, our vitamin D levels have fallen drastically.” – Dr. John Cannell, founder of the Vitamin D Council
Vitamin D does not naturally occur in most common foods. Some foods, like milk and cereal, have been fortified with vitamin D to help people get this important nutrient.
Food sources, with the level of vitamin D per serving.*
- fortified milk (1 cup = 120 IU)
- fortified cereal ( 1 cup = 40 IU
- salmon (3 oz = 794 IU)
- sardines (100 grams = 193 IU)
- egg yolk (1 = 37 IU)
- ricotta cheese (1 cup = 25 IU
To get the amount of vitamin D required by the body many people take a supplement. While there are a number of online tools that can provide a recommended range of IU per day, a blood test is the best and only way to determine an individuals’ exact daily supplement amount needed to reach and maintain an optimal vitamin D level.
We asked the world’s leading experts what they thought were the minimum, maximum and optimum levels of vitamin D serum concentration should be.
The experts in the video above provide the following vitamin D serum concentration ranges:
The following chart summarizes the recommended ranges of vitamin D serum concentration by organization.
Experts agree vitamin D is an important nutrient for our health. Contention around vitamin D arises when trying to determine the optimal recommended daily intake. The debate has percolated over the years, but boiled over in 2010 when the Institute of Medicine (IOM), jointly commissioned by the United States and Canada governments, released a report that concluded people should aim for blood levels of 50 nanomoles per litre (nmol/L) which, they indicated, could be achieved with 400 – 800 International Units (IU) of vitamin D intake per day.
Many anticipated the IOM’s review of approximately 1,000 studies would result in a much higher recommended daily intake of vitamin D. When the report returned a lower than anticipated recommendation, many researchers and associations – including the Endocrine Society – were shocked and undertook reviews of the IOM’s analysis.
It was through third party reviews of the IOM’s process that errors in the IOM’s analysis were identified. In addition to statistical errors, the IOM has been criticized for its anxiety about too much vitamin D.
“I think the committee (IOM) really overblew the safety issue, in an imbalanced way.” – Walter Willett, Professor of Epidemiology and Nutrition and Chairman of the Department of Nutrition at the Harvard School of Public Health and Professor of Medicine at the Harvard Medical School and member of the IOM.
Of the 1,000 studies reviewed there was only one clinical trial claiming risk. In this study elderly women, treated with a single 500,000 IU dose of vitamin D, fell and suffered fractured bones at a higher rate than those in the placebo group. Contributing to the IOM’s anxiety of too much vitamin D, many researchers find this particular study nonsensical and agree it should have been dismissed.
“No one absorbs 500,000 IU a day from the sun, so why would you give that as a supplemental dose?” – Edward Giovannucci, Assistant Professor of Medicine, Harvard Medical School.
New important research demonstrates how wrong the current recommendations are. Breastmilk is the most complete and natural source of food for babies – except it doesn’t have any vitamin D. Vitamin D is the only nutrient that Health Canada recommends to give to babies and to start within a day or two after they are born. But, when mom gets enough vitamin D there is enough for baby in her breastmilk. Mom needs to take at least 6,400 IU/d which is 10 times the amount recommended by Health Canada and the IOM!