We have posted a fair few articles regarding vitamin D and the acculumating evidence does appear to suggest that current intakes and levels are too low for optimal health epeciually where our bones are concerned. As we all know now, Vitamin D works with calcium to help strengthen bones but the ongoing research into this area is suggesting that adequate levels of vitamin D in the bloodstream also appear to boost the power of bisphosphonates. These are the most prescribed drugs used to treat osteoporosis. The most recent study adds to the evidence that the current recommendations for vitamin D may be too low. Late last year, the Institute of Medicine (an American organisation) issued a report that declined to make changes to the recommendation despite many new studies supporting the need for more vitamin D than is typically consumed. In the UK, the National Osteoporosis Society only goes so far as to say; “However, older people, those who do not go out much and people who cover up for religious or cultural reasons may become deficient and 400 iu (international units), or 10 mcg (micrograms), a day is recommended.” If the acculumating work is correct, 400IU’s of vitamin D are well below what is actually needed! In the new study, presented at the annual meeting of the Endocrine Society, researchers found that having a circulating vitamin D level greater than 33 nanograms per milliliter was linked to a seven times greater likelihood of having a good response to bisphosphonates. Bisphosphonates include medications such as Fosamax, Boniva and Actonel. The standard vitamin D blood test measures a component called 25-hydroxy vitamin D and according to the American IOM report, levels of 50 nmol/l to 75 nmol/l (20 ng/ml to 30 ng/ml) are adequate for most normal, healthy adults while in the UK a level below 25 nmol/l (10 ng/ml) is consistent with deficiency with levels between 30-50 nmol/l ( 75-124.8 ng/ml ) being considered a sign of vitamin D “insufficiency”. However, these levels have not been amended since 2006 when the journal Drug and Therapeutics Bulletin published the guidelines. Before we progress… lets get out units sorted out! In American studies vitamin D levels are published in units known as nanograms per militer (ng/ml) where as in the UK the units used are nanomoles per litre (nmol/l). In this post I will display both values for clarity. Vitamin D itself tends to be described in International Units (IU) where 1IU = 0.025 mcg (micrograms). However, in the new study, 83% of people with vitamin D levels less than 50 nmol/l (20 ng/ml) had a poor response to bisphosphonates compared with 77% of people with levels between 50 nmol/l to 75 nmol/l (20 ng/ml and 30 ng/ml), 42% of people with levels of 70 nmol – 100 nmol/l (30 ng/ml to 40 ng/ml) and 24% of those exceeding 100 nmol/l (40 ng/ml). “There has been a lot of controversy over the correct vitamin D levels for people to have,” said the lead author of the study, Dr. Richard Bockman, chief of the endocrine service at Hospital for Special Surgery in New York, in a news release. He concluded by saying that “Vitamin D status should be optimized to improve outcomes in patients taking bisphosphonates.” While the experts trash out the data it looks safe to say that we are, in general, seeing more cases of vitamin D deficiency than previously thought and it would be good to increase the following foods (salmon, tuna, liver, sardines, eggs) or consider a supplement especially over the winter!
National Osteoporosis Society healthy bones information