Vitamin D3 Deficiency Linked to a Surprising Number of Health Concerns

Over the past year, the health effects of vitamin D have continued to be a topic of increased interest and research. A healthy adult should have vitamin D levels greater than 30 ng of 25-hydroxyvitamin D (vitamin D indicator) per ml; however, the National Health and Nutrition Examination Survey (NHANES) findings published in 2009 showed that prevalence of vitamin D insufficiency (defined as serum 25-hydroxyvitamin D levels less than 30 ng/ml) in the U.S. population increased from 55 percent in 1988-1994 to 77 percent in 2001-2004.¹ What is more concerning, the latest statistics indicate 41.6 percent of the population has vitamin D deficiency (defined as serum 25-hydroxyvitamin D concentrations less than 20 ng/mL).²

These overwhelming statistics prompted the Institute of Medicine, the health arm of the National Academy of Sciences, to release an updated report in November 2010 increasing the Recommended Dietary Allowances (RDA) for vitamin D. The new recommendations state that the RDA for individuals between 1 and 71 years of age is 600 IU daily and for those ages 71 years and older is 800 IU daily.³ These RDA values are based on serum 25-hydroxyvitamin D level of at least 20 ng/ml. Thus, these values are recommended to prevent vitamin D deficiency but not vitamin D insufficiency. In fact, many nutritional experts believe these recommendations do not target optimal levels of vitamin D; rather, they merely target achieving marginal levels, at which people may not be deficient but may still be insufficient.

As summer approaches, the increased use of sunscreen along with more time spent year around indoors, in front of the computer and in the office, contributes to insufficiency (below 30ng/ml 25-hydroxyvitamin D) or vitamin D deficiency (below 20ng/ml 25-hydroxyvitamin D).

The research showing the widespread nature of vitamin D deficiency is alarming given the large number of ways vitamin D can support health. While it has long been known that vitamin D plays an important role in bone health, recent research has continued to reveal numerous other ways in which vitamin D is important, including its effects on the cardiovascular system, mood and neurological function, immune health, environmental sensitivities, autoimmune function, as well as healthy cell turnover and blood sugar metabolism.

This article will review the newest research on vitamin D3 and explain why this important nutrient is a crucial component of any health-boosting supplement regimen.

Vitamin D3

Vitamin D is a fat-soluble vitamin that is both made by the body and ingested in the diet. In order for the body to produce vitamin D3 (cholecalciferol), the skin must be exposed to ultraviolet light, like that from the sun. Vitamin D3 is further metabolized in the liver and kidney to create the fully active form of vitamin D. Thus, factors such as variation in sun exposure due to latitude, season, time of day, atmospheric components, clothing, sunscreen use, skin pigmentation, age, body mass index and the incidence of suboptimal health affect vitamin D levels.⁴

Ergocalciferol (vitamin D2) is a form of vitamin D synthesized by radiation of fungus. It is not naturally occurring in humans. However, many healthcare professionals are unaware of the difference in vitamin D2 and D3. A recent study finally clarified the debate, showing that vitamin D3 was significantly more potent than vitamin D2 supplementation. In this new study, researchers found that vitamin D3 is approximately 87 percent more potent in raising and maintaining serum 25-hydroxyvitamin D concentrations and produces 2-3-fold greater storage of vitamin D than equal dosages of vitamin D2. The researchers in this study concluded, “Given its greater potency and lower cost, D3 should be the preferred treatment option when correcting vitamin D deficiency.”⁵

Due to widespread deficiency, testing for vitamin D levels is important for most individuals. Serum concentration of 25-hydroxyvitamin D (also called 25-hydroxycholcalciferol) is the best indicator of vitamin D status as it is the major circulating form of the vitamin in the body.⁶

Brain and Neurological Health

One of the most interesting areas of current research involves vitamin D and neurological function, including mood and cognition. In one new study, researchers investigated cognitive decline and vitamin D levels in adults age 65 and older. The subjects were assessed for serum 25-hydroxyvitamin D levels and evaluated with the Mini-Mental State Examination to determine cognitive function. The study showed that over a 6-year period, the subjects with severe vitamin D deficiency had a 60 percent increase in risk of cognitive decline compared to the subjects with sufficient vitamin D levels.⁷ Similarly, another study found that in individuals age 65 and older, there was nearly a four-fold increased risk of cognitive impairment in the subjects with more pronounced vitamin D deficiency compared to the subjects with sufficient levels.⁸

Other new research indicates that vitamin D deficiency is associated with decreased mood. One study evaluated middle-aged and older men and found that lower serum 25-hydroxyvitamin D levels were associated with suboptimal mood. In fact, they showed that comparing the subjects with the lowest serum 25-hydroxyvitamin D levels to those with the highest, there was a 70 percent increased incidence of lowered mood.⁹ Low vitamin D levels have been linked to several other aspects of neurological function, including brain and nervous system health.^10-11

Blood Sugar Metabolism

Several new studies indicate that vitamin D may play a role in normal blood sugar and insulin metabolism. In one study, researchers evaluated the vitamin D levels and the chance of developing unbalanced blood sugar metabolism. In this study, subjects were evaluated for serum vitamin D levels and followed for 7 years to determine the effects on blood sugar metabolism in this population. The study showed that compared to the subjects with the lowest vitamin D levels, the subjects with the highest vitamin D levels had a 40 percent increase in supporting optimal future blood sugar balance.¹² Similarly, a study of adolescents showed that lower 25-hydroxyvitamin D was associated with unbalanced blood sugar metabolism and insulin inefficiency.¹³

A new clinical trial investigated the impact of vitamin D supplementation on optimal blood sugar balance in subjects with inefficient blood sugar metabolism and low serum vitamin D levels. In this study, 80 subjects were supplemented with 4,000 IU of vitamin D daily for 12 weeks. The subjects were evaluated for hemoglobin A1c (HbA1c), which is a measurement of blood sugar balance over 3 months’ duration. The study found that the subjects were more likely to achieve more balanced HbA1c levels, indicating healthy blood sugar metabolism, if they had higher serum 25-hydroxyvitamin D levels.¹⁴

Immune Function

Vitamin D also plays a role in immune function. Both allergies and unbalanced autoimmune activity can represent a need to support healthy balanced activity of the immune system. A large study evaluated the association between IgE allergic sensitization and vitamin D levels in U.S. children and adolescents. The study revealed that the subjects with allergic sensitization to 11 of 17 factors tested were more likely to have low serum vitamin D levels. Interestingly, peanut, ragweed and oak sensitivities were most strongly associated with vitamin D deficiency.¹⁵

Multiple studies have also shown higher vitamin D levels are related to healthier lung function in people with suboptimal respiratory health. In one study of children with intermittent breathing concerns, researchers found that only 11 percent of the subjects have sufficient vitamin D levels. Additionally, they showed that low vitamin D levels were associated with suboptimal lung function and had an effect on lung health during exercise.¹⁶ A similar study showed that in children with suboptimal respiratory health, those with better-controlled respiratory function had higher serum vitamin D levels compared to children with partially controlled or less well-controlled respiratory function.¹⁷

Another study evaluated the relationship between respiratory health during the fall and winter months and serum vitamin D levels. The results of the study found that the subjects with adequate serum vitamin D levels, defined as 38 ng/ml or more, had a two-fold better supported overall respiratory tract health despite immune challenges from the environment and showed a marked reduction in the percentages of days affected by these challenges.¹⁸

There is also a correlation between adequate vitamin D levels and maintaining healthy, balanced autoimmune activity long-term.^19-20

Cardiovascular Health and More

Recent studies indicate that optimal vitamin D levels correlate to better cardiovascular health, which promotes normal blood pressure and lipid profiles, a healthy vascular system, arterial function, heart activity, and brain health.²¹ In fact, a study with over 7,000 U.S. adults revealed that as vitamin D levels decrease, this can impact blood pressure proportionately.²²

Adequate levels of vitamin D have also been associated with increased health of breast, colon, prostate and bladder cells.^23-26 Additionally, vitamin D sufficiency is related to skin health with age, according to a recent study. The women in this study with photodamage, redness, hyperpigmentation and wrinkling had 5-fold increased odds of being vitamin D insufficient.²⁷

These associations may be related to the connection between low vitamin D and increased inflammation. One new study evaluated serum 25-hydroxyvitamin D levels in people undergoing knee surgery to determine the relationship between vitamin D and the systemic inflammatory response in relation to surgery. The subjects were evaluated for levels of vitamin D and C-reactive protein (CRP), a marker of inflammation, before and after surgery. The study found that compared to pre-operative levels, post-operative levels of serum vitamin D at 2 and 5 days post-surgery decreased by approximately 40 percent and levels of CRP increased. Furthermore, vitamin D levels were still 20 percent below pre-operative levels 3 months after surgery.²⁸

Conclusion

The prevalence of vitamin D deficiency is alarming due to the wide variety of health parameters associated with suboptimal vitamin D levels. Most adults should consider being tested for serum 25-hydroxyvitamin D to determine their vitamin D status and then implement an appropriate supplement regimen based on those results.

References

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21. Anderson JL, May HT, Horne BD, et al. Relation of vitamin D deficiency to cardiovascular risk factors, disease status, and incident events in a general healthcare population. Am J Cardiol. 2010 Oct 1;106(7):963-8.

22. Zhao G, Ford ES, Li C, et al. Independent associations of serum concentrations of 25-hydroxyvitamin D and parathyroid hormone with blood pressure among US adults. J Hypertens. 2010 Sep;28(9):1821-8.

23. Lee MS, Huang YC, Wahlqvist ML, et al. Vitamin d decreases risk of breast cancer in premenopausal women of normal weight in subtropical taiwan. J Epidemiol. 2011 Mar 5;21(2):87-94.

24. Mondul AM, Weinstein SJ, Mannisto S, et al. Serum vitamin D and risk of bladder cancer. Cancer Res. 2010 Nov 15;70(22):9218-23.

25. Touvier M, Chan DS, Lau R, et al. Meta-analyses of vitamin D intake, 25-hydroxyvitamin D status, vitamin D receptor polymorphisms and colorectal cancer risk. Cancer Epidemiol Biomarkers Prev. 2011 Mar 11. Published Online Ahead of Print.

26. Choo CS, Mamedov A, Chung M, et al. Vitamin D insufficiency is common in patients with nonmetastatic prostate cancer. Nutr Res. 2011 Jan;31(1):21-6.

27. Chang AL, Fu T, Amir O, et al. Association of facial skin aging and vitamin D levels in middle-aged white women. Cancer Causes Control. 2010 Dec;21(12):2315-6.

28. Reid D, Toole BJ, Knox S, et al. The relation between acute changes in the systemic inflammatory response and plasma 25-hydroxyvitamin D concentrations after elective knee arthroplasty. Am J Clin Nutr. 2011 Mar 16. Published Online Ahead of Print.