Researchers are beginning to find that low levels of vitamin D may be linked to other diseases, including breast and colon cancer, prostate cancer, high blood pressure, depression, and obesity. The evidence doesn’t prove that too little vitamin D causes these conditions, but that people with higher levels of vitamin D are less likely to get these diseases.
- ~The University of Maryland Medical Center, Last Update May 2013
Just how important is vitamin D3 supplementation? According to Michael Holick, MD, PhD, the world’s leading vitamin D researcher, some of the scientific literature indicates that, “We could probably decrease health care costs across the board by 25% if everybody had optimal vitamin D status.” Part One of this two-part article discussed how vitamin D3 functions in the body, recommended doses, and the science supporting its dietary supplementation in connection with autoimmune diseases (e.g., psoriasis, rheumatoid arthritis, celiac, IBD/Crohn’s, Hashimoto’s), bone disease, cancer, and cardiovascular disease. Discussion of additional compelling scientific evidence continues below.
How The Body Produces and Stores Vitamin D
As noted in Part One, the body produces vitamin D when the sun’s ultraviolet rays strike the skin. Vitamin D also can be obtained from certain foods and dietary supplements. Whatever the source, vitamin D is initially biologically inert and must be activated in the body by two separate enzyme-assisted chemical processes (hydroxylations). In the liver, the first hydroxylation converts vitamin D to 25-hydroxyvitamin D [25(OH)D], also known as calcidiol. In the kidney, the second hydroxylation forms the physiologically active
1,25-dihydroxyvitamin D [1,25(OH)2D], also known as calcitriol.
The level of concentration of 25(OH)D (calcidiol) in blood serum (the component that contains neither red nor white cells) is the best indicator of vitamin D status. 25(OH)D serum concentration indicates exposure to all vitamin D sources, but does not indicate the amount of vitamin D stored in body tissues. Also, it is not clear to what extent 25(OH)D concentration indicates health status or outcomes.
Circulating 1,25(OH)2D (calcitriol) is generally not a good indicator of vitamin D status, in part because serum concentrations are closely regulated by parathyroid hormone, calcium, and phosphate. Also, levels of calcitriol do not typically decrease until vitamin D deficiency is severe.
According to the non-profit, non-governmental Institute of Medicine, most people are at risk of vitamin D deficiency at serum 25(OH)D concentrations below 30 nmol/L, although some are potentially at risk for inadequacy at levels ranging from 30–50 nmol/L. Levels greater than or equal to 50 nmol/L are sufficient for 97.5% of the population, while serum concentrations over 125 nmol/L are associated with potential adverse effects. Like other fat-soluble vitamins, vitamin D is stored in fat tissue, enabling the body to mobilize its own reserves if daily intake falters temporarily. This means that excessive doses of vitamin D can build up to toxic levels, but Harvard Medical School reports, “it takes massive overdosing to produce toxicity.” (See Part One for more on this issue).
Available Forms of Vitamin D3 Supplements
Vitamin D3 (cholecalciferol), the form that most effectively raises blood levels, is derived from fish (the skins of fatty fish or cod liver oil) or lanolin (sheep’s wool). It is available in various supplement doses ranging from 400iu to as high as 10,000iu. Vitamin D3 is available for children and adults in soft gels, tablets or capsules (especially in dry, oil-free form for those with sensitive stomachs), chewable tablets, liquid, drops, and transdermal creams. Some brands offer gluten-free options.
Scientific Support for Vitamin D3 Supplementation
By the end of 2012, nearly 34,000 studies were published on the effects of vitamin D. When considering whether to add vitamin D3 to your dietary supplement regimen, you may want to keep in mind its impact on the health conditions discussed below.
Autism
According to John Cannell, MD, himself mildly autistic, the positive correlation between vitamin D and autism is theoretical. However, studies indicate that vitamin D could likely help children with autism through its: (1) anti-inflammatory and anti-autoimmune activities; (2) great ability to positively impact (upregulate) neurotrophins (the family of proteins that induce the development, function, and survival of nerve and brain cells); and/or (3) stimulation of antioxidant pathways (especially glutathione, which helps detoxify the brain and protects nerve cells and nerve conduction critical to mental processing). Cannell suggests that adequate doses of vitamin D (enough to obtain blood levels of 50-80 ng/mL of calcidiol [25(OH)D]) may be a potential treatment for core symptoms in some cases of children’s autism (Med Hypotheses 2013 Aug).
Cognitive Decline
In 2012, scientists reported that vitamin D deficiency is linked to cognitive impairment (Scand J Clin Lab Invest Suppl. 2012). They explained that vitamin D receptors are widespread in brain tissue, and that the biologically active form of vitamin D has shown neuroprotective effects, including the ability to clear amyloid plaques, a hallmark of Alzheimer’s. They also reported that two large prospective studies indicate that low vitamin D may increase the risk of cognitive decline, but encouraged the development of large, randomized controlled trials to determine whether vitamin D supplementation can prevent or treat Alzheimer’s disease and dementia.
COPD (Chronic Obstructive Pulmonary Disease)
Pulmonary rehabilitation is an important treatment for COPD patients, who are often vitamin D deficient. Exactly how vitamin D affects COPD development is unclear. However, its deficiency increases with the severity of the disease, and studies show that vitamin D can alter immune cell activity, inhibit inflammatory response, and regulate airway smooth muscles. One study of 151 subjects found that higher plasma levels of vitamin D are associated with increased exercise capacity in COPD patients (Ann Med. 2013 Feb). In another study of 50 COPD patients, researchers discovered that monthly doses of 100,000iu significantly improved respiratory muscle strength and oxygen uptake (Respiratory Research 2012 September).
Depression/SAD
It is well-established that vitamin D deficiency can cause seasonal affective disorder (SAD) and general depression. In one four-year study of 12,594 patients, researchers concluded that low vitamin D levels are associated with depressive symptoms and that patients with a history of depression may be an important target for assessment of vitamin D levels (Mayo Clin Proc. 2011 Nov).
According to Dr. Holick, animal studies have shown that vitamin D will elevate mood by increasing serotonin levels in the brain. It is thus thought that healthy vitamin D status can improve people’s serotonin levels, mood, and general feeling of well-being.
Osteoarthritis (OA)
OA is the most common joint disorder in the United States. Old age, female gender, overweight/ obesity, knee injury, repetitive use of joints, bone density, muscle weakness, and joint laxity, all play roles in the development of OA, particularly in the weight-bearing joints.
Low tissue levels of vitamin D may impair bone’s ability to respond optimally to processes in OA and thus predispose to disease progression. One study reported that low intake and low serum levels of vitamin D each appear to be associated with a three-fold increased risk for progression of OA of the knee (Ann Intern Med. 1996 September). Another study found that high levels of vitamin D protected against hip OA characterized by joint space narrowing (Arthritis Rheum. 1999 May). In this writer’s experience, the proper doses of vitamin D with calcium, magnesium, and other micronutrients, reverse osteoarthritis.
Given the ample historical support in the scientific literature for vitamin D3 supplementation in connection with a wide variety of conditions, it would best serve patients to take into account its importance to lifelong health maintenance.
The statements in this article have not been evaluated by the Food and Drug Administration and are not intended to take the place of a practitioner’s advice. Unless otherwise stated herein or otherwise supported by specific research, the natural remedies discussed herein are not intended to diagnose, treat, cure or prevent any disease.
Submitted by Michael Dworkin, PD, CCN, a Registered Pharmacist and State Certified Clinical Nutritionist (CT Certification No. 232), with J. Erika Dworkin, Certified Lifestyle Educator and Board Cert. Holistic Nutrition (pending). Owner of the Manchester Parkade Health Shoppe (860.646.8178, 378 Middle Turnpike West, Manchester, CT, www.cthealthshop.com), Pharmacist Dworkin has been guiding patients since 1956 and is available for consultation by appointment. Erika is available to speak to groups. All statements in this article are research-based and references are available upon request.