Important, need-to-know facts about vitamin D.
Everyone agrees that it’s important to supplement with vitamin D3, but controversy continues to mount with respect to how much should be consumed on a daily basis. In particular, it has caused quite a stir regarding the proper amount to take for adolescents, pregnant women and children.
Make Everyday a “D” Day
So, just how much vitamin D3 should be taken? Well, the answer depends on who you ask. For instance, adequate intake (AI) levels established by the U.S. Institute of Medicine of the National Academy of Sciences are 200 IU for anyone under 50 every day, 400 IU for those who are 50–70 years old, and 600 IU for those older than 70 years old, according to the Mayo Clinic. But, the American Academy of Pediatrics advocated doubling vitamin D recommendations for infants, children and adolescents to 400 IU per day in 2008. And, the American Medical Association urged the U.S. government to increase its recommendation for vitamin D intake, in August of 2008. Last, experts say many people can safely tolerate higher than these amounts, too (upper limits of 1,000 to 2,000 IU daily) (1).
Retailers should ask clients whether they are getting enough vitamin D; in fact, many adults and children are deficient. A team from Massachusetts General Hospital and the University of Colorado, Denver, analyzed data on nearly 5,000 children that were collected for the National Health and Nutrition Examination Survey (2001–2006). It was determined that 20% of children have vitamin D levels of less than 50 nmol/L, which is less than the amount that is considered healthy (75 nmol/L). More than two-thirds of children had less than this amount of vitamin D in their systems. The clinicians also associated their findings with ethnic/cultural background, in that 80% of Hispanic and 92% of non-Hispanic black children had less than 75 nmol/L of vitamin D present in their blood work. And, less than half of all children took a multivitamin containing vitamin D (2).
Shedding Some Light on The Sunshine Vitamin
Bone health. One reason for the deficiency could be our avoidance of the sun. Vitamin D is a fat-soluble vitamin, but our bodies naturally produce it when exposed to sunlight on a daily basis. Covering up and using sunblock disrupts this process. This is significant because vitamin D is so important for overall health.
Vitamin D promotes the growth of cells which are found in healthy joints and is a key for maintaining/achieving proper bone health. The active form, vitamin D3 (cholecalciferol), promotes the absorption of calcium and phosphorus from the intestines. Calcium and phosphorus are incorporated into the bones and make them strong and dense. Thus, vitamin D is paramount for the formation, growth and restoration of bones.
Adults who have vitamin D deficiency are at risk for osteomalacia (bone softening), osteoporosis, osteoarthritis and even hypocalcemia. And, children who are deficient in this vitamin may experience rickets (although common in developing nations) (3). And, it is important to remember that requirements for vitamin D become greater as we grow older (4), since it also can enhance immune function and improve heart health. Still with me? Good, let’s plunge into how vitamin D3 can contribute to immune and heart wellness.
Immune and heart health. As previously discussed, vitamin D can also help regulate the immune system. And, lack of vitamin D has been linked to rheumatoid arthritis, multiple sclerosis, type-1 diabetes and even cancer, according to researchers. Here’s how it helps with immunity: vitamin D in the form of 1,25(OH)2D is an immune modulator. The vitamin D receptor is present in most cells of the immune system, including T cells and antigen-presenting cells (dendritic cells and macrophages).
Also, vitamin D may help guard against influenza, the common cold and tuberculosis (5). Some 18,883 participants took part in the Third National Health and Nutrition Examination Survey. During the survey, it was determined that vitamin D helped boost one’s resistance to colds, even after adjusting for demographic and clinical factors such as season, body mass index and smoking history. The trial, which was published in the journal Archives of Internal Medicine, establishes the need for vitamin D, especially when it comes to thwarting upper respiratory tract infections (6).
According to researchers, vitamin D deficiency increases one’s risk of heart disease and can also be the cause of a plethora of health conditions including diabetes, obesity and high blood pressure (7). Why are heart disease and vitamin D deficiency linked? Although research on this topic is limited, one possible reason may be that those who already have an intrinsic illness tend to spend more time indoors, thus they receive less sunlight than recommended. Another explanation may be that the disease may affect vitamin D levels in one’s system, thereby decreasing levels of this vitamin (8). Says James H. O’Keefe, M.D., director of preventive cardiology at the Mid America Heart Institute in Kansas City, MO, “Vitamin D deficiency is an unrecognized, emerging cardiovascular risk factor, which should be screened for and treated” (7). WF
- ”The Sunshine Vitamin,” WholeFoods Magazine 32 (1), 51 (2009).
- “20% of Children are Vitamin D Deficient,” WholeFoods Magazine 32 (12), 9 (2009).
- S. Liberman, The Real Vitamin & Mineral Book (Avery Publishing Group, New York, NY, 1997).
- Merck & Co., Inc. “Vitamin D,” www.merck.com/mmhe/sec12/ch154/ch154j.html, accessed December 29, 2009.
- The Linus Pauling Institute, “Micronutrient Information Center: Vitamin D,” http://lpi.oregonstate.edu/infocenter/vitamins/vitaminD/index.html, accessed December 30, 2009.
- A.A. Ginde, et al., “Association Between Serum 25-Hydroxyvitamin D Level and Upper Respiratory Tract Infection in the Third National Health and Nutrition Examination Survey,”Arch. Intern. Med. 169 (4), 384–390 (2009).
- J. Warner, ”Too Little Vitamin D Puts Heart at Risk,” www.webmd.com/heart-disease/news/20081201/too-little-vitamin-d-puts-heart-at-risk, accessed December 31, 2009.
- R. Rabin, “Vitamin D Shows Heart Benefits in Study,”
http://well.blogs.nytimes.com/2009/11/16/vitamin-d-shows-heart-benefits-in-study/, December 30, 2009.
Published in WholeFoods Magazine, Feb. 2010