Just today there was an article published in the New York Times about vitamin D. It made mention that vitamin D deficiency has been linked to many diseases. These include fibromyalgia, multiple sclerosis, cancer and heart disease. It also said that we should “be careful” and not run out and start taking vitamin D just yet. It also stated that doctors are recommending that people do not take more than 2,000 international units (IUs) per day as set forth in a new study. They suggest that it may be dangerous. First of all, these “doctors” obviously know nothing about vitamin D because 2,00o IUs is a relatively small and very safe dose. Toxicity of vitamin D does not occur until a patient takes 100,000 IUs per day for 6 or more months at a time. As a matter of fact, a child will make 20,000 IUs from the sun if he is outside for just 15-20 minutes.
So what exactly is vitamin D? Vitamin D is a fat soluble vitamin that is obtained mainly from direct sunlight exposure, but also from dietary sources as well such as fortified milk and fatty fish. Although vitamin D is classified as a vitamin it is actually a hormone. Active vitamin D functions as a hormone because it sends a message to the intestines to increase the absorption of calcium and phosphorus. The most commonly known function of vitamin D is to maintain blood levels of calcium and phosphorous by promoting its absorption. It also helps promote bone mineralization which allows bones to become and stay strong and healthy. Adequate levels of vitamin D is a potent weapon against osteoporosis. These are the basics though. Some of the new research on vitamin D is very interesting and shows that this hormone does more than just produce strong bones. Another wonderful quality to vitamin D is it’s anti-inflammatory property. It appears to act on chemicals called cytokines, which are pro-inflammatory. It suppresses these compounds and therefore has use in conditions such as arthritis, chronic muscle pain, heart disease, vascular disease and stroke to name just a few.
Listed below are just a small sampling of the studies behind vitamin D.
A recent study from the University of California, Los Angeles found that vitamin D supplementation in pregnant women increased the production of an antimicrobial protein called cathelicidin. They concluded that despite the fact that the precise mechanism of vitamin D functioning within the placenta is undetermined, “data suggests that it may play a key role in placental innate immunity.
Source: N. Liu, A.T. Kaplan, J. Low, L. Nguyen, G.Y. Liu, O. Equils, M. Hewison. Vitamin D induces innate antibacterial responses in human trophoblasts via an intracrine pathway. Biology of Reproduction. Published online ahead of print, doi: 10.1095/biolreprod.108.073577.
A long-term study (median follow-up period of 7.7 years) found that low levels of 25-hydroxyvitamin D (Vitamin D) were significantly correlated with variables of inflammation (C-reactive protein and interleukin 6 levels), oxidative burden (serum phospholipid and glutathione levels), and cell adhesion (vascular cell adhesion molecule 1 and intracellular adhesion molecule 1) levels. Collectively supporting the model that low vitamin D levels are independently associated with all-cause and cardiovascular mortality.
Source: 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;1 68(12):1340-1349.
In yet another study extolling the virtues of vitamin D, it has been noted that not only were low serum levels of 25-hydroxyvitamin D associated with higher risk of myocardial infarction but also with controlling factors known to be associated with coronary artery disease.
Source: Giovannucci E, Liu Y, Hollis B, Rimm E. 25-Hydroxyvitamin D and risk of Myocardial Infarction in Men. Arch Intern Med. 2008; 168(11):1174-1180.
Keep Supplementing! Living in a sunny climate is no guarantee of vitamin D status. Recently, a group of researhcers from the Arizona Cancer Center found that nearly 80% of Arizonians had suboptimal vitamin D levels (<30 ng/ml).
Source: Jacobs E, et al. Vitamin D insufficiency in Southern Arizona. AM J Clin Nutr. 2008 Mar 87 (3):608-13.
Peripheral arterial disease (PAD), a condition associated with reduced blood flow in the legs can be caused from arterial narrowing or fatty plaque accumulation. Data analyzed from nearly 5,000 study participants found the greatest prevalence of PAD in participants with the lowest levels of vitamin D.
Source: Melamed ML, Munter P, Michos ED, Uribarri J, Weber C, Sharma J, Raggi P. Serum 25-Hydroxyvitamin D Levels and the Prevalence of Peripheral Arterial Disease. Results from NHANES 2001 to 2004. Arterioscler Thromb Vasc Biol. 2008 Apr 16. Published online ahead of print.
Researchers from Brigham and Women’s Hospital and Harvard Medical School suggest that pre-menopausal women with the highest intakes of both calcium and Vitamin D, from dietary and supplemental sources, may lower their risk of developing breast cancer by nearly 40%.
Source: Lin J, Manson JE, Lee IM, Cook NR, Buring JE, Zhang SM. “Intakes of Calcium and Vitamin D and Breast Cancer Risk in Women”. Archives of internal Medicine. Volume 167, Number 10, Pages 1050-1059.
There are long term benefits for men who take a vitamin D-calcium combination supplement. An Australian study reported that a combination of vitamin D3 and calcium saw increases in bone mineral density in senior men, and the effects were still evident 18 months after the cessation of supplementation.
Source: R.M. Daly, N. Petrass, S. Bass, C.A Nowson. The skeletal benefits of calcium and vitamin D3-fortified milk are sustained in older men after withdraw of supplementation: an 18-month follow-up study. American Journal of Clinical Nutrition. March 2008, Volume 87, Number 3, Pages 771-777.
Vitmamin D has been shown to have immune modulating effects in multiple sclerosis. A review article in the Journal of Neuroimmunology concluded that vitamin D not only effected clinical outcomes of multiple sclerosis, but also enhanced regulatory T cell function.
Source: Smolders, J et al., Vitamin D as an immune modulator in multiple sclerosis, a review. J. Neuroimmunol. (2007), doi: 10.1016/j.jneuroim.2007.11.014
A study conducted by the Department of Rheumatology at Musgrave park Hospital in Belfast demonstrated the majority of fibromyalgia patients referred to a rheumatology clinic have insufficient levels of vitamin D, and there is a clear relationship between low vitamin D levels and high levels of anxiety and depression.
Source: ArmstrongD, Meenagh G, Bickle I, Lee A, Curran S, Finch M. Vitamin D deficiency is associated with anxiety and depression in fibromyalgia. Clinical Rheumatology (2007) 26:55 1-554
The 4 year study of nearly 1,200 healthy postmenopausal women (>55 yr) was a population-based, double-blind, randomized placebo-controlled trial. When analyzed by intention to treat, cancer incidence was lower in the calcium & D women than in the placebo control subjects. However, in multiple logistic regression models, both treatment and serum 25-hydroxyvitamin D concentrations were signifcant, independent predictors of cancer risk.
Source: Lappe, J Et Al. Vitamin D and Calcium Supplementation Reduces Cancer Risk: Results of a Randomized Trial. Am J Clin Nutr 2007;85:1 586-91.
Vitamin D deficiency continues to be a problem for children and adults. In utero and during childhood, vitamin D deficiency can cause growth retardation and skeletal deformities and may increase the risk of hip fracture later in life. Vitamin D deficiency in adults can precipitate or exacerbate osteopenia and osteoporosis, cause osteomalacia and muscle weakness, and increase the risk of fracture. It is now known that most tissues and cells in the body have a vitamin D receptor, and the role that vitamin D can play in decreasing the risk of many chronic illnesses such as common cancers, autoimmune diseases, infectious disease, and cardiovascular disease is of great interest.
Source: Holick, M. Vitamin D Deficiency. N Engl J Med 2007;357:266-81.
A study of 1,179 healthy postmenopausal women found a combination of calcium and vitamin D significantly reduced the risk of all cancer types. Supplemental calcium alone was not a significant preventative, and serum 25-hydroxy vitamin D3 levels were determined to be a potent factor to predict cancer risk.
Source: Lappe J, Travers-GustafsonD, Davies KM, Recker R, and Heaney R. Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial. American Journal of Clinical Nutrition, Vol. 85, No.6, 1586-1591, June 2007.
Vitamin D has been shown to be very deficient, even in populations of people who live in a warm, sunny climate. I routinely recommend 5,000 to 10,000 IUs to my patients with no reservation. I test all of my patients’ blood levels to be sure we are not creating a toxicity and have yet to see a level too high. The benefits are obvious as is the safety. Vitamin D is safe to take and has immense health benefit.