Last week, the Institute of Medicine (IOM) released a statement (PDF) that said most adults do not need to consume any more than 600 IU per day of vitamin D, which may have left you wondering why USANA recommends so much more.
To be sure, we here at USANA were happy to see their recommended intake tripled and the upper limit doubled, but in talking to Dr. John Cuomo, USANA’s Executive Director of Research and Development, he was disappointed that the IOM was so conservative, as there is a growing body of research that supports a number of protective benefits from significantly higher intakes.
Most conservative estimates have suggested that, for optimal health, blood levels of circulating vitamin D need to be above 30 ng/mL (75 nmol/L). USANA’s Research and Development (R&D) team is always looking to validate current research and explore new areas. So, they decided to look more closely into how much vitamin D most people would need to take in order to reach that level. Findings from the winter study they conducted earlier in the year are available on www.usana.com (PDF), and now the data is in for the summer portion of their vitamin D study. The results were pretty surprising to me, so I thought I would provide you with a recap, with the help of USANA Senior Scientist Brian Dixon, Ph.D. and Marketing Manager Camille Fletcher.
As I am sure you know, vitamin D is known as the sunshine vitamin. With the second part of the study being done in the summer, I would have thought that the vitamin D levels would have been significantly higher than in the winter study because we are outside more. Not so. In fact, the difference of average vitamin D levels was equal to consuming only 300 IU of vitamin D or increasing circulating levels by 3 ng/mL when compared to levels in winter. A pretty negligible difference, and, in USANA’s opinion, further evidence that RDAs are not nearly high enough.
Brian shared with me a variety of factors that limit the amount of vitamin D we are exposed to: where we live (geographic latitude), season, age, melanin content of skin, the use of sunscreen or sun-obscuring clothing, and a lack of outdoor activity.
Vitamin D Deficiency
Due to all of these factors, and the fact that vitamin D is unique because very little can be obtained through a normal diet, you will not be surprised to find out that more than 1 billion people worldwide and 30-40% of the U.S. population between the ages of 15-49 are vitamin D deficient.
Perception vs. reality is interesting, isn’t it?
Also of note in the second phase of the study: USANA Associates/Preferred Customers were found to have 35% higher vitamin D levels than non-USANA participants. When the data from both the summer and winter studies is combined, USANA Associates/Preferred Customers had 50% higher vitamin D levels, and were 5.5 times more likely to have optimal vitamin D levels above 30 ng/mL.
Wow — the power of USANA and vitamin D.
In light of last week’s IOM announcement, the R&D team looked again at the data. The research shows that nearly 70% of adults taking 600 IU or less of supplemental vitamin D have circulating levels below the minimum recommended threshold of 30 ng/mL. In fact, some people require up to 12 times that amount to maintain optimal levels of vitamin D. That is why USANA’s recommended daily intake of vitamin D remains at least 4,000 IU per day. Of course every person’s individual needs are different, so it is best to work with your physician to determine what is right for you.
Brian and the rest of the R&D team will be sharing their findings in scientific, peer-reviewed journals in the coming months and will continue adding to the scientific evidence that proves the importance of optimal intakes of vitamin D. Well done team!!