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Vitamin D supplements do improve bone health

November 24th, 2013

by Jacques Allou, PharmD student

Vitamin D is a fat-soluble vitamin that is naturally present in very few foods. It is available as a dietary supplement, and is also produced inside the body when ultraviolet rays from sunlight strike the skin and trigger vitamin D synthesis.1

In the past decade, wonderful claims has been made about the role of vitamin D in the prevention and treatment of conditions as varied as osteoporosis, heart disease, cancer, diabetes, dementia, neuromuscular and immune function, and reduction of inflammation.1 Reports from authoritative bodies and reviews show that there is good consensus on the role of Vitamin D in growth and development of bone. Adequate supply of vitamin D is required for efficient calcium absorption and for the maintenance of normal blood levels of calcium and phosphate that are needed for the normal mineralization of bone and bone health.1,2 Not only does vitamin D promote bone growth, it does also protect against cardiovascular disease. In a study published on June 23 in the Archives of Internal Medicine, a team of Austrian scientists revealed that low blood levels of vitamin D appear to have an increased risk of death overall and from cardiovascular.3 A recent consensus panel estimated that about 50 – 60 percent of older individuals in North America and the rest of the world do not have satisfactory vitamin D status, and the situation is similar for younger individuals. Blood levels of vitamin D lower than 20 to 30 nanograms per milliliter have been associated with falls, fractures, cancer, autoimmune dysfunction, cardiovascular disease and hypertension.3   Vitamin D was the leader in dietary supplement sales in 2009, recording 82% sales growth.4

In this recent article by Fox News, Researchers have indicated that Vitamin D may actually do very little to guard against osteoporosis, contrary to popular belief.5 The researchers from the University of Auckland in New Zealand analyzed data from 23 studies involving 4,082 healthy adults with an average age of 59.6  In these studies, bone mineral density – the measure of bone strength and the amount of bone mineral present – was examined at five different sites in the body: lumbar spine, femoral neck, total hip, total body and forearm. They found that adults who took supplements of vitamin D for an average period of two years did not see any improvements in their bone health, apart from a small increase in bone density around their femoral neck.  However, the study authors believe such a small increase is unlikely to be clinically significant.6

I was surprised to learn that. I do not agree with the article because the study has some limitations. There could be a strong possibility that bone mineral density in middle-aged women is a poor predictor of who will eventually have osteoporosis as already suggested by Dr. Clifford.7 It could be that vitamin D and calcium need to be taken together, and that they help only when a person is really low on either or both. Researchers have shown that, even though calcium is the main bone health nutrient, its absorption in the gut and use by bone tissue is dependent on vitamin D. Therefore, regardless of the adequacy of calcium intake, poor vitamin D status will limit calcium absorption.8 This explains why interventions using combinations of calcium and vitamin D produce more consistent results than interventions based on calcium alone.9 The link between vitamin D and calcium has been known for decades, so studying vitamin D alone does not make it appropriate.

My self-care recommendation will not be changed, based on the above discussed limitations. When counseling patients, I will stress that calcium and vitamin D work synergistically, and that foods and supplements containing these nutrients should be eaten or taken regularly as part of a balanced diet.

Half of all people around the world are deficient in vitamin D and therefore at increased risk for serious and potentially fatal conditions.3 What will we do as pharmacists to protect the cardiovascular and bone health of our aging patients?

 

References

  1. Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Calcium and Vitamin D. Washington, DC: National Academy Press, 2010. http://www.iom.edu/Reports/2010/Dietary-Reference-Intakes-for-Calcium-and-Vitamin-D.aspx   Assessed November 12, 2013
  2. European Food Safety Authority. Scientific Opinion of the Panel on Dietetic Products, Nutrition and Allergies on a request from the Association de la Transformation Laitière Française related to the scientific substantiation of a health claim on vitamin D and bone growth. The EFSA Journal (2008) 827, 1-10. http://www.efsa.europa.eu/en/efsajournal/doc/827.pdf Assessed November 12, 2013
  3. Dobnig H, Pilz S, Scharnagl H, et al. Independent Association of Low Serum 25-Hydroxyvitamin D and 1,25-Dihydroxyvitamin D Levels With All-Cause and Cardiovascular Mortality. Arch Intern Med. 2008;168(12):1340-1349. doi:10.1001/archinte.168.12.1340.
  4. Tousrounis C, Denneby C. Introduction to Dietary Supplements. Handbook of Nonprescription Drugs: An Interactive Approach to Self-Care, 17th Ed Washington DC, American Pharmacists Association Press; 2012: 955-956.
  5. Fox News. Vitamin D supplements do not improve bone health study finds. Fox News. http://www.foxnews.com/health/2013/10/14/vitamin-d-supplements-do-not-improve-bone-health-study-finds/ Published October 14, 2013. Assessed November 1, 2013
  6. Ian RR, Mark JB, Andrew G. Effects of vitamin D supplements on bone mineral density: a systematic review and meta-analysis. The Lancet. 2013; DOI: 10.1016/S0140-6736(13)61647-5.
  7. Shute N. More Evidence Against Vitamin D To Build Bones In Middle Age http://m.npr.org/news/Health/232028261. Published October 12, 2013. Assessed November 1, 2013
  8. Fleet JC, Schoch RD (2010) Molecular mechanisms for regulation of intestinal calcium absorption by vitamin D and other factors. Critical Reviews in Clinical Laboratory Sciences. 47, 4, 181-195
  9. Tang BM, Eslick GD, Nowson C, Smith C, Bensoussan A. Use of calcium or calcium in combination with vitamin D supplementation to prevent fractures and bone loss in people aged 50 years and older: a meta-analysis. The Lancet. 2007; 370, 9588, 657-666.

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5 Responses to “Vitamin D supplements do improve bone health”

  1. Nathanael J Smith Says:

    Wow! That is amazing to see how so many people in the world have a vitamin D deficiency. Many people actually call vitamin D the “sunshine vitamin.” It would appear that shunning the sun, as you mentioned, may be detrimental. In addition, I liked how you incorporated the relationship between calcium and vitamin D in bone health and function. Many people rely solely on calcium for bone health and do not understand that without vitamin D, calcium cannot be absorbed from the diet. One thing that I found interesting in the deficiency of vitamin D, according to WebMD, was that one symptom could be severe asthma in children. Another reason to eat a balanced diet!

  2. McKenzie Shenk Says:

    From a google search, it seems that vitamin D deficiency can lead to depression. I have heard about people who get depressed when there is no sunlight, known as Seasonal Affective Disorder. One article from Psychology Today mentioned the potential link between depression and vitamin D deficiency. However, the author remarked that causality has yet to be proven. From numerous studies, however, date seems to point to better moods with increased vitamin D supplementation. At the end, you focused on bone health in the elderly. Have studies been done specifically in the elderly to determine vitamin D’s effect on calcium’s absorption. Since the elderly have increased gastric pH, maybe vitamin D supplementation will not help at all. Or since vitamin D is a fat soluble vitamin, increasing fat consumption may assist in the absorption of vitamin D and subsequently calcium. This depends of whether people of advanced age can adequately absorb fats.

  3. Mallory Martin Says:

    I remember not too long ago, people starting discovering the strong negative affects of sun exposure. They emphasized the faster aging of the skin and, most prominently, the increase of prevalence of skin cancer particularly in Australia and areas with thinner ozone layers and more UVA and UVB radiation exposure. As a response to this, many people retaliated my avoiding the sun all together. I believe this vitamin D deficiency is a consequence of this push away from too much sun exposure and how unbalanced our diets have become. I don’t think more sunlight is the answer, I do agree that supplementation is the route to take. After reading this article, I suddenly became much more appreciative of the addition of vitamin D to certain food products. The example that came to mind is vitamin D enriched milk. I would recommend this to patients since it will be a good source of both calcium and vitamin D together. Milk also contains a large amount of fat and will aid in further absorption as McKenzie pointed out. Honestly I would recommend it to healthy patients as well. It’s just a good idea. I would like to see a study of the elderly and bone density comparing those who drink regular milk verses vitamin D enriched milk.

  4. Lauren Williams Says:

    Vitamin D was not a vitamin that I would expect half of the world to be deficient in! I assumed that since its synthesis is triggered by UV rays from sunlight, which is available to everyone, it would be a vitamin that most people would have an adequate supply of. I wonder if this deficiency is more prevalent in locations like Alaska and Iceland, where there are days with only 0 to 5 hours of sunlight during the winter. If not, is it because of the the diets of the people in these locations? Are their diets heavier with vitamin D from foods such as fish?

    I’m happy that you stressed the importance of the relationship between vitamin D and calcium. I didn’t realize that calcium absorption abilities were dependent on the presence of vitamin D. This answered my question of how and why vitamin D is used to promote bone health. Knowing of the dependence of calcium on vitamin D, I am more apt to recommended calcium-vitamin D combination products to patients seeking supplementation for bone health because of its effectiveness. I agree with Mallory that this deficiency “is a consequence of the push away from sun exposure and how unbalanced our diets have become”. It’s necessary that we help our patients find a balance in sun exposure and diet. As pharmacists, if we’re going to protect the bone health of our aging patients, we must inform them on how to adjust their diet to include both vitamin D and calcium. Suggesting a time outside in the sun wouldn’t hurt either.

  5. Tirhas Mekonnen Says:

    I think your comments and your explanation about the relationship between sunshine and calcium are very informative.
    I am very surprised by the statistics; these many people have lack of vitamin D? I think health care professionals would be encouraged to advice their patients to take calcium containing diet like vitamin D milk, fish, and vitamin D containing fruit juices. Although each counseling is patient specific, there are also problems that are very common to many people just like vitamin D deficiency.
    I think that to treat osteoarthritis, it is also important to investigate the cause. What I am interested the most after reading your article is that, “what causes bone density to go low in some people and not in other?”. Many people especially older women take vitamin D supplements. I am sure age has a lot of impact on hormonal changes which may cause the need of calcium supplement.
    As you also explained bone formation, strength and health has a lot to do with calcium although vitamin D is also important. In addition, my other question is that does absorption of calcium completely dependent on the amount of vitamin D? Your article is motivates me to know more.
    Overall, I think the information you have provided is very important to health care professionals as well as to patients who want to know more about the importance of vitamin D for bone strength.

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