Researchers reveal concerning calculation error:

ALARM: We are getting far too little vitamin D

The recommended dietary intake of vitamin D in the UK is 17 times lower that it should ideally be in order to provide sufficient protection against disease. That is what two teams of US scientists have concluded independently of each other.

For decades, the recommended daily intake level for vitamin D from dietary sources has been far too low. Now, researchers have issued a red flag warning over the low recommendations, claiming that they are unable to ensure adequate blood levels of vitamin D. In the United States, the current reference nutrient intake level for vitamin D is 15 micrograms/day. However, the figure should be 11-12 times greater, the worried scientists state. In the UK, the situation is far more critical. Here, the recommended intake level should be 17.5 times greater than the current 10 microgram/day recommendation.

Not enough for protection

The warning comes from two teams of scientists who have conducted a thorough analysis of the documentation on which the American health authorities base their vitamin D recommendations. Both teams, one from the University of California San Diego, the other from the University of Creighton, have reached the same conclusion independently of each other and agree that the current recommendations are a far cry from what they should ideally be in order to offer sufficient protection.
"Calculations by us and other researchers have shown that these doses are only about one-tenth those needed to cut incidence of diseases related to vitamin D deficiency," Dr. Cedric F. Garland, adjunct professor at UC San Diego's Department of Family Medicine and Public Health, is quoted as saying in a press release issued by Creighton University. The researchers encourage the health authorities to recommend much higher intake levels for vitamin D on behalf of these findings.

Supplements are necessary

Experts around the world generally seem to agree that the optimal blood levels of vitamin D should be around 50 nmol/L, and a deficiency will occur at levels lower than 20 nmol/L. The problem, however, is figuring out how much vitamin D one needs to consume in order to reach those blood levels. This is where the scientists from the two universities claim that it requires an intake level of at least 175 micrograms daily to reach an adequate blood level of vitamin D. Such intake levels would require the use of supplements.

Far less than what the body produces

What the scientists also point to is the fact that even a daily intake of 175 micrograms of vitamin D, is far below the levels that are synthesised by the skin in response to sunlight during the summer period. According to the Institute of Medicine (who has established the current US guidelines for vitamin D intake) no harmful effects have been seen with vitamin D intake at those high levels.
It is yet to be seen if the health authorities in the United States or in Europe, including the UK, are willing to listen to the two teams of scientists and adjust recommendations accordingly. Nonetheless, the researchers are very clear in making their statement.
"The error has broad implications for public health regarding disease prevention and achieving the stated goal of ensuring that the whole population has enough vitamin D to maintain bone health," Dr. Cedric Garland announced in the above mentioned press release.

Sources:

Heaney, R.P. et al. 2015. Letter to Veugelers, P.J. and Ekwaru, J.P., A Statistical Error in the Estimation of the Recommended Dietary Allowance for Vitamin D. Nutrients 2014, 6, 4472-4475

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