The best doctor gives the least medicines.
To perform its best, the body needs at least 30 different vitamins and minerals every day.  While each plays an essential role in keeping us healthy, some are more critical than others. To add further complexity to the mix, there are some nutrients which we are most likely to be deficient in, due to dietary gaps and other lifestyle factors. Moreover, our bodies’ nutritional needs evolve with age.
One critical vitamin in which many individuals are deficient is vitamin D. Failure to take in adequate amounts of this vitamin can produce widespread effects, and we may notice symptoms ranging from sluggishness to more alarming consequences, including bone loss.
Below, we’ll take a deeper look how this powerful nutrient helps to support optimal health. We’ll also discuss appropriate values to help you determine whether you’re a good candidate for supplementing vitamin D with nutraceuticals.
Role of Vitamin D
The body can take in vitamin D in two ways: through exposure to sunlight and through supplements. It is found naturally in very few foods, and even the foods it is found in contain only small amounts of the nutrient. 
Some fish and dairy products do contain minimal amounts of the vitamin, but not nearly enough to meet the recommended daily intake. For these reasons, many individuals aren’t getting enough vitamin D – when coupled with dietary gaps, lack of sunlight increases deficiency risk significantly.
When we don’t get enough vitamin D, it may have some impacts on our mood and how we feel, but there are also underlying effects taking place which may not be readily observable. Vitamin D is produced by the body when a person’s bare skin is exposed to UV rays from sunlight. It is synthesized from cholesterol when this exposure takes place. Thereafter, the role of vitamin D takes many forms.
Role of Vitamin D
The role of vitamin D takes on many forms including:
Vitamin D Acts Like a Hormone
Vitamin D is involved in many important functions inside the body that support optimal health. It functions like a hormone, and every cell has a receptor for it. One job of vitamin D is to regulate the absorption of calcium and phosphorus.
Specifically, calcium absorption increases through calbindin (a calcium binding protein) in the small intestine with the assistance of calcitriol, the hormonally active metabolite of vitamin D.
The role of vitamin D in calcium absorption is so essential because together, these nutrients promote bone health – an extremely important factor for older women, who face a greater risk of osteoporosis. Without ample vitamin D, bones can become brittle, thin, or misshapen.
The risk of falls among the elderly is reduced by 20% with vitamin D supplementation, and the risk of hip and vertebral body fractures are also reduced.  Sufficient levels of the vitamin can also prevent osteomalacia in children, also known as rickets – a condition characterized by the softening and weakening of bones. 
Vitamin D and Inflammation Reduction
Vitamin D also has other critical functions in the body outside of bone health. It makes itself available to tissues all over the body and is turned into a chemical, a process which is called hydroxylation. As such, it supports a broad range of bodily activities including neuromuscular and immune function, modulation of cell growth, and reduction of inflammation. 
The link between vitamin D and immune system health is so strong that researchers have even observed an association between increased susceptibility to infection and vitamin D deficiency. 
Moreover, low levels of vitamin D in populations across the globe have been associated with autoimmune disease including type 1 diabetes, Crohn’s disease, and multiple sclerosis, while more recent studies indicate infections such as tuberculosis may also be linked to low vitamin D. 
In terms of combatting inflammation, the vitamin-D receptor appears to bind directly to DNA to activate a specific gene inhibiting inflammatory responses. This suggests that vitamin D could contribute to the control of immune and inflammatory conditions. 
Yet, despite the many powerful ways in which vitamin D contributes to optimal health and perhaps even aids in disease prevention, there continues to be an epidemic deficiency of the nutrient. Just how widespread is the vitamin D issue, and what are the consequences of not getting enough?
Low Vitamin D
Research suggests a staggering portion of the population is deficient in vitamin D. Low vitamin D was observed in three-quarters of U.S. teens and adults, and compared to results measured just a decade earlier, the trend is continuing to worsen.
While 45% of more than 18,000 people examined in 1994 had 30 nanograms per milliliter or more of vitamin D, the level physicians consider sufficient for wellness, ten years later that figure dropped to 23%.  With that being said, slightly more recent findings show some improvement: in 2011, 42% of the population exhibited low vitamin D levels, with the greatest deficiencies appearing in minority groups. The number increases to 69.2% in Hispanics and 82.1% in African-Americans. 
Nevertheless, the numbers are still concerning. Beyond dietary insufficiencies, what’s to blame for this sharp decline? For one, it is suspected that the shift towards safe sun practices have contributed to declining vitamin D levels. Even SPF 15 cuts the body’s vitamin D production by 99%.  We also see increases in deficiencies in some areas further north of the equator, where winter weather can inhibit sun exposure.
Specifically, people living at latitudes above 40 degrees are at a particular risk of a deficiency, because even if they do choose to venture outdoors during the wintertime, sunlight during that time of year is ineffective at stimulating the conversion of pre-vitamin D to vitamin D. 
Symptoms of Low Vitamin D
With low vitamin D becoming such a widespread phenomenon, you might think the majority of the population would be ailing. While there are indeed some noticeable signs and symptoms of a vitamin D deficiency, these can often be attributed to other factors such as the aging process.
These symptoms of low vitamin D may also have a number of other culprits. Impaired wound healing and bone loss, on the other hand, may be more concrete signs of a deficiency.
Symptoms of Low Vitamin D
Symptoms of a vitamin D deficiency include:
Populations with Increased Risk of Vitamin D Deficiency
While the best way to increase vitamin D levels is by pursuing more sunlight exposure, this simply isn’t feasible for everyone – especially those living in areas further from the equator. Therefore, taking supplemental vitamin D is usually advised to help individuals reach their recommended daily intake. It is also critically important for certain populations to have their vitamin D levels checked.
Are You at Risk of Low Vitamin D?
Populations of increased risk of a vitamin D deficiency include:
Currently, the Reference Daily Intake (or RDI, the level of a nutrient considered sufficient to meet the requirements of most healthy individuals) of vitamin D for teens and adults up to 70 years old is 600 international units (IU). People over the age of 70 need a bit more and are advised to take in 800 IU. It is important to note that vitamin D is fat-soluble, meaning that it is absorbed by the body instead of being processed out via urine as is the case with water soluble vitamins.
Thus, it is critically important to take only trusted nutraceuticals, as toxicity is possible with fat-soluble vitamins. Also, be mindful of the form of vitamin D you take. It is available in both D2 and D3. The latter is the form that is synthesized in humans and the most effective form to take to increase vitamin D levels throughout the body.
Understanding the Role of Vitamin D – In Conclusion
For most people, it seems daunting to satisfy so many different dietary requirements each day. Not only are there calories and macronutrients to consider, but also micronutrients such as vitamin D. If you feel overwhelmed by these guidelines, you’re not alone.
At Cenegenics, our expert-led nutrition panel will help you optimize your eating habits in a way that is manageable and sustainable for the long-term. Moreover, we’ll perform a comprehensive assessment of your health by measuring and monitoring biomarkers to determine where any deficiencies may lie. Our nutraceuticals are made from the highest quality ingredients without any harmful additives to ensure your body receives all of the nutrients it needs to function at its best, both now and into the future.
If you’re interested in learning how the Cenegenics program can help you optimize your wellness through improved nutrition, among many other benefits, contact your nearest location today.
Next Steps in Combatting Low Vitamin D
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About the Contributor
Global Director of Nutrition & Exercise
Rudy Inaba is Cenegenics’ Global Director of Nutrition & Exercise. He is a recognized fitness and sports nutrition consultant with nearly 15 years of experience in clinical exercise physiology and lifestyle management. After pursuing his Master of Science in Clinical Exercise Physiology at the University of Nevada Las Vegas, Rudy joined Cenegenics where he leads 20 clinical locations nationwide in their advancements in kinesiology, nutritional biochemistry, and their analyses of industry research & market trending.
This guide was produced with contributions from the following key resources:
The Cenegenics Education and Research Foundation
The Textbook of Age Management Medicine Volume 1: Mastering Healthy Aging Nutrition, Exercise and Hormone Replacement Therapy
Jeffrey Park Leake, M.D., CPT
Dr. Jeffrey Park Leake is a Partner and Director of Education at Cenegenics Elite Health specializing in age management and wellness. Having trained hundreds of physicians worldwide, Dr. Leake is also the Director of Education for the Clinical Strategies for Healthy Aging course at AMM Educational Foundation.
Todd David Greenberg, M.D., CSCS
Dr. Todd Greenberg is a practicing physician with a broad range of expertise, including wellness, exercise, sports injuries, and MRI of sports injuries. He is a Radiology Clinical Associate Professor at the University of Washington.
 “Listing of vitamins.” Harvard Health Publishing. 14 Aug. 2017. Retrieved from URL: https://www.health.harvard.edu/staying-healthy/listing_of_vitamins
 “Vitamin D Fact Sheet for Health Professionals.” National Institutes of Health (NIH). 09 Nov. 2018. Retrieved from URL: https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/
 Leake, Jeffery Park, M.D., CPT and Todd David Greenberg, M.D., CSCS. The Textbook of Age Management Medicine: Volume 1. Leake-Greenberg Ventures, LLC. 2015.
 NIH, see above.
 NIH, see above.
 Aranow, Cynthia, MD. “Vitamin D and the Immune System.” Journal of Investigative Medicine. 01 Aug. 2012. Retrieved from URL: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3166406/
 Hewison M. “Vitamin D and immune function: an overview.” Proceedings of the Nutrition Society. Feb. 2012. Retrieved from URL: https://www.ncbi.nlm.nih.gov/pubmed/21849106
 National Jewish Health. “How vitamin D inhibits inflammation.” ScienceDaily. 23 Feb. 2012. Retrieved from URL: https://www.sciencedaily.com/releases/2012/02/120223103920.htm
 Adit A. Ginde, MD, MPH et al. “Demographic differences and Trends of Vitamin D Insufficiency in the Us Population, 1988-2004.” Archives of Internal Medicine. 2009.
 Forrest KY and Stuhldreher WL. “Prevalence and correlates of vitamin D deficiency in US adults.” Nutritional Research. Jan. 2011.
 Adit A. Ginde, see above.
 Leake, Jeffery Park, M.D., CPT, see above.
 Tello, Monique, MD, MPH. “Vitamin D: What’s the ‘right’ level?” Harvard Health Publishing. 19 Dec. 2016. Retrieved from URL: https://www.health.harvard.edu/blog/vitamin-d-whats-right-level-2016121910893