From the D*action Panel of Vitamin D Scientists/Researchers

“It is important to stress that there is no disagreement in the scientific community about the importance of vitamin D for total body health. Where there is disagreement it is about how much is needed to insure that the bulk of the American population achieves vitamin D’s full benefits. There is an impressive body of scientific evidence supporting levels higher than the IOM panel is currently recommending, and for reasons that are not entirely clear, the panel has discounted that evidence. The public needs to know that that evidence exists so that they can make up their own minds. It’s helpful in making those decisions, to know that intakes higher than the IOM recommends are safe. For me, that makes the decision easy. Even if the evidence for a higher intake were uncertain (and I don’t believe it is), intakes 2-5 times the IOM recommendations would carry a good chance for benefit at essentially no cost and no risk.”

“Finally, I believe that the presumption of adequacy should rest with vitamin D intakes needed to achieve the serum 25(OH)D values (i.e., 40–60 ng/mL) that prevailed during the evolution of human physiology. Correspondingly, the burden of proof should fall on those maintaining that there is no preventable disease or dysfunction at lower levels. The IOM has not met that standard.”

Dr. Robert P.Heaney, MD
John A Creighton University Professor and Professor of Medicine
Creighton University

“I think that we should encourage people to get their blood level of 25(OH)D tested. For those who worry about the cost of this testing, the solution is not to save money by testing less; the solution is to lower the cost of an over-priced test. While we tend to approach public health problems with ‘one-size-fits-all’ solutions, I think it would be much better to tailor the vitamin D dose and frequency for each person — based on their baseline level, response to treatment, and the likelihood that they will take a daily vitamin. For example, for those who have a difficult time remembering to take a daily vitamin D drop or pill, they might aim for weekly treatments or even monthly.”

“Vitamin D is a hormone and, just like any other hormone, good health requires a level that is not too low but also not too high This optimal level may differ for different people — based on lifestyle and genetic factors — but my guess is the optimal level for most people is a 25(OH)D level around 40 ng/ml.”

Carlos Camargo, MD DrPH
Associate Professor of Medicine
Harvard Medical School

“Because most people do not get adequate vitamin D in typical diets, and because of the potential downsides of excessive sun exposure, most people may benefit from vitamin D supplements. Several groups are at risk for vitamin D deficiency or less-than-adequate intakes-in particular, the elderly, dark-skinned individuals, obese individuals, and those who avoid the sun. People who live in more northern latitudes can only make vitamin D from March through September; supplies stored from summer sun exposure must last for many months, and by late winter, most of these individuals may be deficient. Even in sunny climates, many people avoid the sun. Although definitive evidence is not available currently for the optimal level for all conditions related to vitamin D, supplements of at least 1,000 to 2,000 IU per day of vitamin D may be warranted. I suggest not taking more than 2,000 IU per day of vitamin D in supplement form for prolonged times without specific medical reasons until more definitive data are available concerning the benefits and risks. For those at a higher risk of vitamin D deficiency, a larger daily supplement dose, on the order of 3,000-4,000 IU, may be required to achieve adequate blood levels.”

Dr. Edward Giovannucci, MD, ScD
Professor of Nutrition and Epidemiology
Harvard School of Public Health

“Based largely on observational studies, serum 25(OH)D level-disease outcome for cancers, cardiovascular disease, infectious diseases, autoimmune diseases and falls/fractures, I have published five studies estimating the reduction in all-cause mortality rate and the economic burden of disease in which I assume that mean population level serum 25(OH)D levels double from about 20 ng/ml to about 40 ng/ml. The countries or regions were Canada, the Netherlands, Nordic countries, the U.S., and Western Europe. In these studies, there was an estimated 15-20% reduction in all-cause mortality rate, corresponding to about a two-year increase in life expectancy, and about a 10% reduction in the direct economic burden of disease. There are over 100 diseases for which a beneficial effect of vitamin D has been found or proposed. Since vitamin D is so inexpensive to manufacture, increasing serum 25(OH)D levels is the most effective way to reduce disease rates and increase health status. And, it doesn’t require lifestyle modifications.”

William B. Grant, Ph.D.
Sunlight, Nutrition, and Health Research Center

“Any increase from the current levels requires, in the short-term, promotion of supplement use (it currently does for those over 50 years of age, but has not been stated emphatically enough). So, say it’s the worst-case scenario of 400 IU for everyone up to age 50, and then 800 IU for 50+. We know from intake studies that people cannot get much more than 200 IU per day – there’s not enough choice in the marketplace nor levels in existing foods, then that means everyone needs a supplement. According to DRI interpretation, a safe intake is anything between the RDA and the UL.”

  • Once people get used to idea of supplement use, taking 800 IU makes no sense – at least 1,000 IU and then really should target what is needed.
  • Government and organizations that promote health/prevent disease need to be more engaged in this area.
  • Hopefully the RDA will be derived from meeting a specific target 25(OH)D – again, even if it’s worse case of 50 nmol/L (20 ng/ml), it opens up to need for testing to ensure people are over it.
  • We can use risk/benefit to our advantage as the risk of taking high doses is highly unlikely even at levels above the UL but certainly at the UL (let’s hope for a 5000 IU or more UL). The message can be – there is risk to NOT taking additional vitamin D.
  • Canadian adults 60-79 years of age have higher 25(OH)D levels than younger adults and the speculation is supplement use- so it is possible to improve levels with multiple strategies of moderate sun exposure, fortified foods and supplement use.
  • Call for more research into diseases related to D, especially in African American population.
  • Recognition that in low income groups, supplements are not within easy reach as that $10-$20 purchase is money needed elsewhere- so need ways to distribute. We have a D donation program here with help of DDROPS for infants in low income families. From what I understand, supplements cannot be purchased using food stamps in the US.

Susan J. Whiting, Ph.D.
Professor of Nutrition & Dietetics
University of Saskatchewan

“Hepatitis C recovery is improved with vitamin D and standard of care therapy from 40% to 96% if levels are above 80nmol/l. Also with levels >95nmol/l, influenza rate is reduced by 50%. There is a 90% reduction of post operative infections for hip surgery with 2,000 IU/day.”

Gerry Schwalfenberg, MD
Family Practice, Alberta

“I would strongly hope that the IOM opts for a substantial increase in the DRI for vitamin D. There is now substantial and compelling evidence that, in addition to its requirement for skeletal integrity, vitamin D sufficiency reduces the risk of development of a number of cancers, contributes to cardiovascular health, and stimulates immune responses to infectious diseases, all of which are essential for healthy aging. The combination of basic and clinical research supporting a central role for vitamin D in boosting innate immune responses to infection is particularly strong. Several clinical studies have provided evidence for an inverse association between circulating 25-hydroxy D levels and rates of both viral and bacterial infection, and suggest that levels over 38ng/ml are required for optimal protection.”

John H. White, PhD
McGill University

“We recommend implementation of the GrassrootsHealth Call to Action. More specifically, and with additional details, we recommend:

  • Universal testing of serum 25(OH)D at birth and annually through age 15 years, in nadir month (March in the northern hemisphere)
  • Testing of all adults every 2 years for serum 25(OH)D, preferably in March
  • Vitamin D3 intake optimally determined by test results, targeting 40-60 ng/ml
  • Pending testing, minimum intake for all men, women and children 1 year and older is 2,000 IU/day
  • Minimum intake of infants should be 1,000 IU/day
  • Contraindications are rare, but include hypercalcemia, active sarcoidosis, active granulomatous diseases, and Williams Syndrome
  • Upper limit should be 8,000 IU/day
  • Future directions likely: Serum 25(OH)D in women at high risk of breast cancer will eventually become 80-85 ng/ml; this may require intakes of 4,000 – 8,000 IU/day of vitamin D and my require some prudent, solar exposure of the body, not to exceed the minimal erythemal dose, generally 5-20 minutes at noon during warm months

Upper limit less than 8000 IU/day – Many persons will require 8,000 IU/day for reducing breast cancer risk, there is no good rationale for a lower UL based on present best evidence.”

Cedric F. Garland, Dr. PH, FACE
University of California San Diego School of Medicine and Moores Cancer Center