There are 5 forms that have been isolated. Vitamin D3, or cholecalciferol, and D2, or ergocalciferol, are the two major forms. These two forms have to go through two conversions, one in the liver and then one in the kidneys to be converted to Calcitriol (1, 25-Dihydroxycholecalciferol), the active form of Vitamin D in the body.
Calcitriol plays an important role in the maintenance of several organ systems. A major role is calcium absorption necessary for bone growth and development. Vitamin D deficiency results in impaired bone mineralization and leads to bone softening diseases such as rickets in children, and contributes to osteoporosis in adults. It’s important to key biological functions vital to one’s health, but increasingly, researchers are learning its importance in preventing diseases throughout life.
Today, as growing numbers of Baby Boomers celebrate their fiftieth-plus birthdays, concerns about the brittle bones and fractures associated with advanced age has renewed attention on vitamin D. Researchers have found that the proportion of people with adequate vitamin D blood levels had dropped 50% between 1988 and 1994.
Deficiency of vitamin D can result from a number of factors including: inadequate intake coupled with inadequate sunlight exposure, disorders that limit its absorption from the gastrointestinal tract, conditions that impair conversion of vitamin D into active metabolites, such as liver or kidney disorders and body characteristics such as skin color and body fat.
Doctors have reported a trend of vitamin D deficiency in a majority of their patients, including patients in sunshine states such as Florida and Arizona. According to some researchers there is an unrecognized epidemic of vitamin D deficiency among both women and men who are middle aged and older. In a study published in the journal Archives of Internal Medicine, researchers from Harvard University and the University of Colorado found that 70% of whites and 97% of blacks in the U.S. have insufficient blood levels of vitamin D.
Deficiency is defined as any level below 20 nanograms per milliliter, based on guidelines adopted at the 13th Workshop Consensus for Vitamin D Nutritional Guidelines in 2007. Previously, deficiency was defined as less than 11 nanograms per milliliter, but the value was upgraded based on more recent research.
New organizations such as www.Grassrootshealth.net have been created to increase awareness about the benefits of vitamin D. There is increasing evidence which has implicated vitamin D deficiency as a major factor in the pathology of at least 17 varieties of cancer as well as heart disease, stroke, hypertension, autoimmune diseases, diabetes, depression, chronic pain, osteoarthritis, osteoporosis, muscle weakness, muscle wasting, birth defects, periodontal disease, and more ( Lappe et al. AJCN 2007).
Considerable debate exists among scientist as to the amount necessary for optimal health. There is also variability that exists among the various tests available and among laboratories. A standard reference material for vitamin D became available in July 2009 that will now permit standardization of values across laboratories.
Patients often ask how much vitamin D is adequate. The first step is to get tested. A simple blood test gives your doctor a baseline reading of your current level. It’s recommended to get tested at least twice per year, usually in the early spring and late summer. A blood calcidiol (25- hydroxyl-vitamin D) level is the accepted way to determine vitamin D status. For optimal health, many experts believe that your blood levels should be between 40- 60 ng/mL.
So what is the best way to get vitamin D? Natural sources of vitamin D include: fatty fish such as herring, salmon, mackerel, sardines, tuna, as well as whole eggs and beef liver. The reality is that on average, the U.S. diet provides only 100 IU/day. Adequate intake has been defined as 200 IU/day for infants to 50 years of age, 400/day for 51 -70 years old and 600/day over 70. The Institute Of Medicine is reconsidering vitamin D and calcium recommendations.
The easiest way to get vitamin D is by supplementation, but make sure it’s in the D3 form. Responsible sun exposure is also another option, although there are risks associated with it. Light-skinned people can produce all the vitamin D they need from just 15 – 30 minutes of the sun on the face, hands and back per day, while darker skinned people may need up to five times as much sun exposure. Here in the southwest, vitamin D synthesis is best achieved between 11:00 a.m. and 1:00 p.m. The angle of the suns rays earlier or later creates what is called the zenith angle, and it prevents vitamin D production.
For the latest information about vitamin D, blood tests, and supplementation please contact Dr. Howell @ 480-474-4441