Editor’s Note: This blog post originally appeared on the Amway Answers blog.
Mainstream media picked up on it, and experts on both sides of the debate weighed in. Anytime the results of more than 1,000 published studies are considered, conflicting opinions will surface, so Marc Lemay, Ph.D, a senior scientist at the Nutrilite Health Institute who helped formulate Nutrilite Vitamin D3 plus K2, gave his honest assessment. We are republishing it, in Marc’s words, below:
What’s this about Vitamin D in the news?
The IOM recently updated the recommended dietary allowances (RDAs) for Vitamin D and Calcium, raising the Vitamin D to 600 IU per day (800 for those older than 70), which is three times higher than the previous RDA.
Then why do so many vitamin D supplements provide 2,000 IU or more per tablet?
Vitamin D first became well known in the 1920s for its effects on bone health when it was discovered that milk fortified with a small amount of vitamin D (100 IU per cup) could prevent the bone disease rickets in children. Later research showed that vitamin D has other important health benefits at doses far higher than that. There are many vitamin D scientists who recommend 2,000 daily IU of vitamin D3 for everybody age one year or older. Some scientists recommend more than that: The Vitamin D Council recommends that most people get 5,000 IU per day.
It is safe to take 2,000 IU every day?
As always with supplements, check with your doctor if you have a medical condition. The IOM states the Safe Upper Limit of vitamin D at 4,000 IU for persons age 9-69. A recent benefit-risk assessment by the Council for Responsible Nutrition found an even higher upper limit to be safe. My personal recommendation? Check with your doctor and get your current vitamin D level tested. A good level to strive for is 40-80 ng/ml (nanograms per milliliter), measured with a 25-hydroxy test.
Why would anybody take more than what the IOM recommends?
There is much evidence that vitamin D helps with more than bone health and that it plays an important role in multiple body parts and functions. The strongest evidence is that people with higher levels of vitamin D are at lower risk of many types of cancers, especially colon and breast cancer. This evidence is mostly laboratory and population-study based, meaning that no pivotal double-blind, placebo-controlled studies have established that link. Those studies would be too long, expensive and morally questionable to conduct.
How much should I take?
Talk to your doctor. The IOM and other health organizations make general, population-wide recommendations. Your doctor will make the right recommendation for you. For most people, 2000 IU per day is a good start.
A few other important considerations:
- Some people don’t need to supplement during the summer if they get regular sun exposure.
- Vitamin D works with other micronutrients, most notably magnesium. There is some suggestion in scientific literature that people who are high in vitamin D and low in magnesium are at higher risk for developing kidney stones. If you take extra vitamin D, it’s a good idea to supplement with magnesium.
How much vitamin D do you take?
I take two to three tablets of the 2,000 IU Nutrilite product once or twice a week. On weeks when I get to spend more time at the beach, I take less. I also get my vitamin D level tested, and it’s hovering near the lower recommended limit at 40 ng/ml.
Thanks to Marc LeMay and Joel Van Kuiken for making this post possible. The views expressed here are Marc’s and do not necessarily reflect an official position taken by Amway. Glass of milk photo by Filomena Scalise from FreeDigitalPhotos.net.