A new study carried out in Taiwan and published on the Journal of Food and Drug Analysis has found that the majority of Taiwanese people are deficient in vitamin D, with vegans being most at risk.
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The study, which was led by Ming-Yeh Yang and Ching-Yuan Huang of Tzu-Chi University, aimed to develop a rapid, sensitive and feasible method to determine 25(OH)D3 levels in blood for clinical assessment.
Vitamin D levels can affect a person’s risk of developing cancer, cardiovascular disease, hypertension, and depression. Clinical studies have suggested that vitamin D deficiencies can lead to chronic conditions, with asthma in children being a significant concern. Conversely, excessive intake of vitamin D can lead to hypercalcemia, demonstrating that balance in vitamin intake is important.
Diet and supplements are the usual source for vitamin D, with the major compounds in humans being vitamin D2 and D3. D2 can only be obtained through the diet, but parts of D3 can be synthesized through sun exposure
One common analytical technique for assessing vitamin D in plasma or serum is immuno-assay. Another technique is based on chromatographic separation followed by non-immunological detection.
Clinical practices related to vitamin D have been held back due to difficulties in measuring its active forms in serum. As such, establishing an accurate base is important for nutrition surveys and studies with collaborative proficiency testing schemes, and any clinical tests should operate with adequate accuracy, specificity, and sensitivity standards.
The sum of 25(OH)D3 and 25(OH)D2 levels is believed to be the best biomarker to evaluate levels of vitamin D in biological fluids.
Now, scientists have used liquid chromatography-mass spectrometry (LC-MS/MS) without derivization, and gas chromatography-mass spectrometry (GC-MS) to analyze vitamin D levels in vegetarian and non-vegetarian Taiwanese people.
The scientists analyzed 117 blood samples (44 male and 73 female). 25(OH)D3 was extracted from the plasma, its derivatives were used for LC-MS/MS and GC-MS/MS analysis.
The practical performances of LC-MS/MS with AD derivitization (AD-LC-MS) and GC-MS/MS with TMS derivatization (TMS-GC-MS/MS) were also compared with traditional immunoassay methods with two blood samples.
TMS-GC-MS/MS was further utilized to carry out a clinical nutrition survey focussing on vitamin D. Participants were grouped as non-vegetarians, egg-vegans, and strict vegans.
The study concluded that 25(OH)D3 could be detected by LC-MS/MS, but the “precision of a direct LC-MS/MS method (without derivatization) is insufficient for clinical assessments.”
The study also shows that TMS-GC-MS/MS can achieve “similar sensitivity” as AD-LC-MS, being able to detect 25(OH)D3-TMS at concentrations as low as 6.25ng.
However, when compared with traditional immunoassay methods, the study’s chromatographic methods showed a “slight underestimation bias”.
Vitamin D deficiency is defined as a measurement of less than 30ng/mL. This study found that most Taiwanese people, both vegetarian and non-vegetarian, are deficient in vitamin D.
It was also concluded that because of diet, male vegans may be the most at risk from vitamin D deficiency, with strict vegans showing the lowest levels of 25(OH)D3. However, there were no significant differences between genders outside of the strict vegan group.
Researchers claim their method “provides a rapid, sensitive and cheap procedure to estimate the 25(OH)D level” in blood samples, with complete analysis costing $0.70 per sample.
As severe vitamin D deficiency is considered a global issue, the researchers of this study hope that the results gained can be used to “develop nutritional suggestions and monitor risk to improve health”. The scientists point out that further studies will be necessary to determine whether policy interventions will have a positive effect.
Yang, M. Y., et al. Using gas chromatography and mass spectrometry to determine 25-hydroxyvitamin D levels for clinical assessment of vitamin D deficiency. Journal of Food and Drug Analysis. January 2019.