Is Vitamin D Beneficial or Detrimental to Consumer Health?
In early 2011, Euromonitor International reported on the mixed perspective of the health benefits of vitamin D. Later that year, a follow-up article was published by Euromonitor International providing a positive outlook for the vitamin D market as a result of then recent studies linking the vitamin to health benefits beyond just bone and skeletal strength. Vitamin D is now back in the spotlight as new clinical trials casting doubt on such benefits have resurrected the controversy.
A Booming Business
Vitamins and dietary supplements is the fastest growing consumer health category and overtook OTC remedies as the most lucrative in 2011. Of all vitamin and dietary supplements, vitamin D has posted the highest growth rate since 2007 by a substantial margin with a 20% CAGR. Strong growth and global sales reaching US$934 have allowed this vitamin to close the revenue gap with more mature supplements such as minerals, vitamin C, and fish oils/omega fatty acids. The root of such robust development is the numerous studies linking vitamin D to a variety of health benefits.
Global Vitamins and Dietary Supplements Retail Value Sales and Growth, 2007-2012
Source: Euromonitor International
It has been long-established that the vitamin is an important nutrient for bone health and key in combating osteoporosis, but recent research has linked it to other debilitating illnesses such as cancer, multiple sclerosis, Parkinson’s disease and more. According to the study “Vitamin D, Race, and Risk for Anemia in Children” published on 10 October 2013, in the Journal of Pediatrics, vitamin D deficiency may also be linked to anemia in children. Scientists at the Johns Hopkins Children’s Center examined blood samples from over 10,400 subjects and found that vitamin D levels were consistently lower in children with low hemoglobin levels. A separate study conducted this year, “Dietary vitamin D deficiency in rats from middle to old age leads to elevated tyrosine nitration and proteomics changes in levels of key proteins in brain: Implications for low vitamin D-dependent age-related cognitive decline” and published in Free Radical Biology and Medicine in December 2013, reported that vitamin D deficiency may damage the brain. During the study, rats that were fed a low vitamin D diet had poor cognitive function and even developed brain damage over time. Although this study was performed on rodents, previously conducted research has linked low levels of vitamin D to Alzheimer’s disease and dementia. Yet another study this year, led by Todd Doyle of the Department of Psychiatry and Behavioral Neurosciences at the Loyola University Chicago Stritch School of Medicine, found that pain and depression among diabetic women significantly improved following a regimen of vitamin D supplementation. The researchers presented their findings on 24 October 2013, at a research conference at Loyola’s Health Sciences Campus.
With so many studies indicating the importance of maintaining appropriate levels of vitamin D to fend off a variety of serious chronic illnesses, this vitamin’s publicity boomed. Doctors and celebrities alike have praised it as a wonder vitamin, touting it as essential to our health. And to the joy of vitamin providers, experts have emphasized the difficulty in sustaining a naturally sufficient level of vitamin D through sun exposure and diet and, therefore, the importance of taking vitamin D supplements. As a result, manufacturers have aggressively developed product portfolios to include or expand upon their vitamin D offering. With such a positive outlook, strong growth is anticipated to continue and vitamin D is projected to reach retail sales of US$1.3 billion by 2017, up from US$315 million in 2007.
The Controversy Continues
As more studies link vitamin D deficiencies with a variety of diseases, and doctors and media continue to promote the benefits, it is easy for consumers to believe that taking vitamin D supplements will keep them safe from a series of serious illnesses. However, a recent study calls into question the suggested conclusions from previous vitamin D analyses. In the study “Vitamin D Status and Ill Health: A Systematic Review” published in The Lancet Diabetes & Endocrinology on 6 December 2013, French researchers reviewed the data from 462 previously conducted studies on the effects of vitamin D on various health indicators, excluding bone and skeletal wellness. 63% of the studies reviewed were observational in nature and a large number of these established a relationship between high levels of vitamin D and reduced prevalence of various health risks. However, the other 37% of the studies, which were randomized clinical trials and more reliable in establishing a causal relationship, found no effect of the vitamin on decreasing disease occurrence. According to the team of researchers, “the discrepancy between observational and intervention studies suggests that low [vitamin d] is a marker of ill health… which would explain why low vitamin D status is reported in a wide range of disorders.”
This study may cause consumers to think twice about vitamin D’s capability to reduce the risk of cancer, diabetes, multiple sclerosis, obesity, dementia, and cardiovascular disease. However, it does not stop there. Another meta-analysis published in The Lancet on 11 October 2013, “Effects of Vitamin D Supplements on Bone Mineral Density: A Systematic Review and Meta-Analysis,” questioned the long-standing medical recommendation that older populations should take vitamin D to maintain bone and skeletal health. The researchers determined that vitamin D supplementation is not necessary in older adults who do not have specific bone-related risks. After analyzing 23 previously held studies, they “found very little evidence of overall benefit of vitamin D supplementation on bone density” and the cost associated with taking the supplement is not justified.
The Council for Responsible Nutritional (CRN) has been quick to debate these studies that query the benefits of vitamin D. Duffy MacKay, the vice-president of scientific and regulatory affairs for the CRN, challenged the claim that vitamin D supplementation has little impact on bone density, saying that the study isolated its effect without taking into consideration interactions with calcium. He said that “vitamin D is necessary for calcium absorption and bone density, and therefore the two nutrients work in combination to provide a protective effect for helping to prevent osteoporosis” (statement from the Council for Responsible Nutrition, 10 October 2013). At a later date, he addressed the study “Vitamin D Status and Ill Health: A Systematic Review” which questions the vitamins role in non-bone related health issues, saying that findings “should not be misinterpreted, that vitamin D has no value” (Bloomberg, 6 December 2013).
The Future of Vitamin D
There is no question that the current preventative health and wellness life style trend will continue into the future. However, the popularity of the specific vitamins and dietary supplements is volatile and can change based upon new research findings. The variety of recent studies released, both promoting and challenging the health benefits of vitamin D, have the potential to make an impact on the market, especially in the United States where approximately half of adults spent US$748 million on the vitamin in 2012. However, vitamin D sales should not be greatly influenced by recent studies in the near term. While many savvy consumers are improving their knowledge of vitamins and dietary supplements, there is an equally large population simply following the health craze or doctor’s orders without fully understanding what they are taking and why. As long as health officials and organizations continue to promote the vitamin, the public will adhere.
Nevertheless, as health literacy continues to improve, the vitamin D market will depend on future studies and evidence. There are currently five randomized controlled trials being conducted which are testing whether or not vitamin D reduces fractures, cancer, cardiovascular disease, diabetes, and dementia. These studies will take a big step towards providing more conclusive evidence of the benefits of vitamin D and have the potential to make or break its market. Initial results will not be available until 2017.