It is estimated that anywhere from 30 to 100% of Americans, depending upon their age and community living environments, are deficient in Vitamin D. More than half of all American children are vitamin deficient. Supposedly almost 3/4s of pregnant women are vitamin D deficient, predisposing their unborn children to all sorts of problems. Worldwide, it is estimated that the epidemic of vitamin D deficiency affects one billion people. In my practice over 80% of patients whose vitamin D levels I check are deficient. No one is exactly sure why this is happening apart from the fact that we spend too much time indoors and when we go out into the sun, we lather sunscreen on ourselves. I think it must be more than that. But whatever the reason, the reality is we have a major epidemic on our hands. How much vitamin D you need varies with age, body weight, percent of body fat, latitude, skin coloration, season of the year, use of sun block, individual variation in sun exposure, and – probably – how ill you are.
As a general rule, old people need more than young people, big people need more that little people, fat people need more than skinny people, northern people need more than southern people, dark-skinned people need more than fair skinned people, winter people need more than summer people, sun block lovers need more than sun block haters, sun-phobes need more than sun worshipers, and ill people may need more than well people. What I and many of my colleagues around the country are finding is that even people spending what we thought was adequate amount of time in the sun, are still showing up with low blood vitamin D levels. I am not sure why at this stage but there is an easy and cheap solution…vitamin D supplementation. There is no clear pattern of symptoms. In fact many people remain asymptomatic despite low levels. But here are the more common symptoms Vitamin D deficiency has been shown to play a role in almost every major disease. It is impossible to generate too much vitamin D in your body from sunlight exposure: your body will self-regulate and only generate what it needs.
Although very rare, it is possible to overdose and become toxic with supplementation as vitamin D is a fat soluble vitamin and therefore stored in the body for longer periods of time. Therefore if you are taking 5,000 IU or more daily, you should have your blood levels monitored approximately every 3 months. The only blood test that can diagnose vitamin D deficiency is a 25-hydroxy-vitamin D (25 OH vitamin D). Unfortunately, some doctors are still ordering the wrong test, 1,25-dihydroxy-vitamin D. In fact a common cause of high 1,25-dihydroxy-vitamin D is a low 25(OH)D or vitamin D deficiency. So when doctors see the 1,25-dihydroxy-vitamin D is normal or high and tell their patients that they are OK, they are often vitamin D deficient. Your doctor should do this test for you. Unfortunately even some of the labs, in particular Qwest, have had problems with correct results, usually giving erroneously high results. If you don’t want to go through your doctor, the ZRT lab does a blood spot test that you can order without going through a doctor.
The current ranges for “normal” are 20 to 55 ng/ml. These are much too low!!! They may be fine if you want to prevent rickets or osteomalacia, but not for optimal health. The ideal range for optimal health is 50-80 ng/ml. At least once a year especially at the beginning of winter. If you are supplementing, I suggest you monitor your vitamin D levels approximately every 3months until you are in the optimal range. If you are taking high doses (10,000 IU a day) your doctor must also check your calcium, phosphorous, and parathyroid hormone levels every 3 months.Canada-US study published in Journal of Clinical Endocrinology & Metabolism recommends young people be screened for low vitamin D levels This release is available in French. Montreal, December 10th, 2008 -Insufficient vitamin D can stunt growth and foster weight gain during puberty, according to a new study published in the Journal of Clinical Endocrinology & Metabolism. Even in sun-drenched California, where scientists from the McGill University Health Centre (MUHC) and the University of Southern California conducted their study, vitamin D deficiency was found to cause higher body mass and shorter stature in girls at the peak of their growing spurt.
While lack of vitamin D is common in adults and has been linked to diseases such as osteoporosis, cancer and obesity, until this study, little was known about the consequences of insufficient vitamin D in young people. The research team measured vitamin D in girls aged 16 to 22 using a simple blood test (25-hydroxy vitamin D). They also assessed body fat and height to determine how vitamin D deficiency could affect young women's health. "The high prevalence of vitamin D insufficiency in young people living in a sun-rich area was surprising," says study lead author, Richard Kremer, co-director of the Musculoskeletal Axis of the MUHC. "We found young women with vitamin D insufficiency were significantly heavier, with a higher body mass index and increased abdominal fat, than young women with normal levels." Vitamin D fosters growth, healthier weight The researchers examined 90 Caucasian and Hispanic girls and discovered that young women with normal vitamin D levels were on average taller than peers deficient in vitamin D.
Yet in contrast to what's been previously reported in older women, their investigation found no association between lack of vitamin D and bone strength. "Although vitamin D is now frequently measured in older adults, due to a higher level of awareness in this population, it is rarely measured in young people - especially healthy adolescents," says Dr. Kremer. "Clinicians need to identify vitamin D levels in younger adults who are at risk by using a simple and useful blood test," says the co-author, Dr. Vicente Gilsanz, head of musculoskeletal imaging at the Children's Hospital Los Angeles of the University of Southern California. "Because lack of vitamin D can cause fat accumulation and increased risk for chronic disorders later in life, further investigation is needed to determine whether vitamin D supplements could have potential benefits in the healthy development of young people," added Dr. Gilsanz. "Vitamin D Status and its Relationship to Body Fat, Final Height and Peak Bone Mass in Young Women," published in the Journal of Clinical Endocrinology & Metabolism, was authored by Richard Kremer of the McGill University Health Centre, Patricia P. Campbell and Vicente Gilsanz of the Children's Hospital Los Angeles of the University of Southern California, and Timothy Reinhardt of the U.S. Department of Agriculture's National Animal Disease Center.
This work was supported by the U.S, Department of the Army; the National Institutes of Health (a part of the U.S. Department of Health and Human Services); the Natural Sciences and Engineering Research Council of Canada (NSERC); and the Dimensional Fund Advisors Canada Inc (a subsidiary of U.S.-based Dimensional Fund Advisors). About the McGill University Health Centre: www.muhc.ca/research The Research Institute of the McGill University Health Centre (RI MUHC) is a world-renowned biomedical and health-care hospital research centre. Located in Montreal, Quebec, the institute is the research arm of the MUHC, the university health center affiliated with the Faculty of Medicine at McGill University. The institute supports over 600 researchers, nearly 1200 graduate and post-doctoral students and operates more than 300 laboratories devoted to a broad spectrum of fundamental and clinical research. The Research Institute operates at the forefront of knowledge, innovation and technology and is inextricably linked to the clinical programs of the MUHC, ensuring that patients benefit directly from the latest research-based knowledge.