January 30, 2012
The Most Accurate and Reliable Measurement of Your Vitamin D Status
Vitamin D is one of the most powerful healing chemicals in your body with the ability to prevent hundreds of diseases. One of the most important determinants of your vitamin D status is how you supplement and assess your optimum levels. Researchers have unveiled the development of a revolutionary reference methodology that promises to assure more accurate and reliable measurements of vitamin D status.
Vitamin D is well known as the "sunshine vitamin" because human skin makes the nutrient upon exposure to sunlight. The body can produce up to 10000 IUs in inly 10 minutes of exposure to sunlight during peak hours.
Writing in the journal Analytical Chemistry, researchers from the US National Institute of Standards and Technology (NIST) and the National Institutes of Health's Office of Dietary Supplements (NIH-ODS), report the development of a Standard Reference Material (SRM) for the determination of vitamin D in the form of 25-hydroxyvitamin D [25(OH)D] in human serum.
Exposure to sunlight and vitamin D has been shown to effectively deal with toxins including medications. A study from the Swedish medical university Karolinska Institute has shown that the body's ability to break down medicines may be closely related to exposure to sunlight, and thus may vary with the seasons.
Karen Phinney of the NIST, explained that renewed interest in vitamin D status due to increasing interest in its links to diseases like rickets, osteoporosis, multiple sclerosis and Parkinson's disease, mean that researchers need an accurate way to measure its levels in the blood.
They noted that the current method for testing vitamin D -- by detecting levels of a vitamin D metabolite called 25(OH)D -- does not always provide accurate or reliable results.
Low levels of vitamin D have been correlated with high incidences of cancer, heart disease, autoimmune disorders, poorly functioning immune systems, and musculoskeletal disorders.
To help researchers and industry to assess vitamin D levels with consistent and accurate methods, the team developed a Standard Reference Material called SRM 972 -- the first certified reference material for the determination of the metabolite in human serum (a component of blood).
"This reference material provides a mechanism to ensure measurement accuracy and comparability and represents a first step toward standardization of 25(OH)D measurements," said Phinney and her team.
A recent study from the American Journal of Clinical Nutrition found that 2 days after knee surgery serum levels of vitamin D dropped 40%, and that three months later levels were still 20-30% below presurgery levels. These researchers showed that this directly correlated with acute inflammation after surgery.
Surprisingly, they also found that the study participants were deficient in vitamin D before the surgery--so deficient that they had secondary hyperparathyroidism!
More research is linking vitamin D to musculoskeletal disorders. A recent study in Headache shows that headache increases with latitude and during seasons with shorter days. They correlated this information with evidence that vitamin D has alleviated headaches in some studies to form a hypothesis that Vitamin D deficiency plays a key role in the development of headache in some people.
Another recent study from the Scandinavian Journal of Primary Care found "a high prevalence of hypovitaminosis D in patients with non-specific musculoskeletal pain, headache, or fatigue."
Vitamin D refers to two biologically inactive precursors - D3, also known as cholecalciferol, and D2, also known as ergocalciferol. Both D3 and D2 precursors are transformed in the liver and kidneys into 25- hydroxyvitamin D (25(OH)D), the non-active 'storage' form, and 1,25-dihydroxyvitamin D (1,25(OH)2D), the biologically active form that is tightly controlled by the body.
The essential role of vitamin D in bone metabolism and calcium homeostasis has been known for many years, however recently the vitamin has been the subject of renewed interest -- due to its functions in the regulation of the cell cycle, cell death and differentiation.
The authors noted that both epidemiological data and animal model studies "have pointed toward a link between vitamin D status and cancer risk," in addition to other serious illnesses including multiple sclerosis and Parkinson's disease.
Although 1,25(OH)2D is the physiologically active metabolite of vitamin D, the research team explained that it has limited use as an indicator of vitamin D status because its levels in the body are influenced by concentrations of both other compounds including parathyroid hormone (PTH) and calcium.
"Similarly, vitamin D is also a poor marker of vitamin D status because it is rapidly hydroxylated to form 25(OH)D," said Phinney and her team.
In contrast, 25(OH)D is not rapidly broken down, and as such this has become a preferred indicator of vitamin D nutritional status.
However the team noted that there are several important factors "that must be considered in the measurement of 25(OH)D," including the realization that the compound is generally bound to protein that must be removed before analysis.
In addition, they warned that the analysis method should respond equally to metabolites of both forms of vitamin D, even if concentrations of 25(OH)D2 and 25(OH)D3 are not reported separately.