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home:tests:25d [05.18.2013] – [Notes and comments] new study shows 25D max benefits at 21ng/mL joyfulhome:tests:25d [03.22.2017] – [Healthy people who do not supplement have naturally low levels of 25-D] sallieq
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-MP patients getting their 25-D levels tested should ensure the [[home:tests:dtesting|relevant instructions]] are closely followed including the freezing of blood samples.+MP patients getting their 25-D levels tested should ensure the [[home:tests:dtesting|relevant instructions]] are closely followed.
  
 ===== Interpreting a 25-D test ===== ===== Interpreting a 25-D test =====
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 ==== Units of measurement ==== ==== Units of measurement ====
-On the Marshall Protocol study site, 25-D levels are typically discussed using ng/ml units rather than pmol/L. The ratio between the two units is: 1 ng/ml = 2.4 nmol/L. To convert nmol/L into ng/ml, multiply by 0.40, as you see in this example:+On the Marshall Protocol study site, 25-D levels are typically discussed using ng/ml units rather than pmol/L. The ratio between the two units is: 1 ng/ml = 2.5 nmol/L. To convert nmol/L into ng/ml, multiply by 0.40, as you see in this example:
  
   60 nmol/L * 0.40 = 24 ng/mL   60 nmol/L * 0.40 = 24 ng/mL
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 Observational studies show that populations which avoid vitamin D consumption have naturally low levels of 25-D and remain healthy with such levels.  Observational studies show that populations which avoid vitamin D consumption have naturally low levels of 25-D and remain healthy with such levels. 
-  * A study which tested the level of 25-D in 90 “healthy, ambulatory Chilean women” showed that 27% of the premenopausal and 60% of the postmenopausal women had 25-D levels under 20 ng/ml.(({{pubmed>long:17290161}}))      + 
-  * A study on healthy Bangladeshi women found that approximately 80% of the women had a level of 25-D under 16 ng/ml.(({{pubmed>long:16500882}}))  +  * A study which tested the level of 25-D in 90 “healthy, ambulatory Chilean women” showed that 27% of the premenopausal and 60% of the postmenopausal women had 25-D levels under 20 ng/ml. (({{pubmed>long:17290161}}))      
-  * In a 1992 study, healthy full-term infants from China had serum concentrations of 25-D ranging from an average of 5 ng/ml to 14 ng/ml.(({{pubmed>long:1578308}}))+  * A study on healthy Bangladeshi women found that approximately 80% of the women had a level of 25-D under 16 ng/ml. (({{pubmed>long:16500882}}))  
 +  * In a 1992 study, healthy full-term infants from China had serum concentrations of 25-D ranging from an average of 5 ng/ml to 14 ng/ml.  (({{pubmed>long:1578308}}))
 ==== Patients with chronic diseases naturally downregulate levels of 25-D ==== ==== Patients with chronic diseases naturally downregulate levels of 25-D ====
  
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 Roux-en-y gastric bypass (RYGB) surgery is associated with dramatic improvements in obesity-related comorbidity, but also with nutritional deficiencies. Vitamin D concentrations are depressed in the severely obese, but the impact of weight loss via RYGB is unknown. We determined associations between adiposity and systemic 25-hydroxyvitamin D (25(OH)D) during weight loss and the immediate and longer-term effects of RYGB. Plasma 25(OH)D concentrations and fat mass (FAT) were determined by immunoassay and air displacement plethysmography, respectively, at 0 (before RYGB surgery), and at 1, 6, and 24 months in severely obese white and African American (AA) women (n = 20). Decreases in adiposity were observed at 1, 6, and 24 months following RYGB (P < 0.05). Plasma 25(OH)D concentrations increased at 1 month (P = 0.004); a decreasing trend occurred over the remainder months after surgery (P = 0.02). Despite temporary improvement in vitamin D status, a high prevalence of vitamin D insufficiency was observed (76, 71, 67, and 82%, at baseline, 1, 6, and 24 months, respectively), and plasma 25(OH)D concentrations were lower in AA compared to white patients (P < 0.05). Strong positive baseline and 1 month cross-sectional correlations between FAT and plasma 25(OH)D were observed, which remained after adjustment for age and race subgroup (β = 0.76 and 0.61, respectively, P = 0.02). In conclusion, 25(OH)D concentrations increased temporarily and then decreased during the 24 months following RYGB. The acute increase and the positive associations observed between adipose tissue mass and systemic 25(OH)D concentrations suggest storage in adipose tissue and release during weight loss</blockquote>. Roux-en-y gastric bypass (RYGB) surgery is associated with dramatic improvements in obesity-related comorbidity, but also with nutritional deficiencies. Vitamin D concentrations are depressed in the severely obese, but the impact of weight loss via RYGB is unknown. We determined associations between adiposity and systemic 25-hydroxyvitamin D (25(OH)D) during weight loss and the immediate and longer-term effects of RYGB. Plasma 25(OH)D concentrations and fat mass (FAT) were determined by immunoassay and air displacement plethysmography, respectively, at 0 (before RYGB surgery), and at 1, 6, and 24 months in severely obese white and African American (AA) women (n = 20). Decreases in adiposity were observed at 1, 6, and 24 months following RYGB (P < 0.05). Plasma 25(OH)D concentrations increased at 1 month (P = 0.004); a decreasing trend occurred over the remainder months after surgery (P = 0.02). Despite temporary improvement in vitamin D status, a high prevalence of vitamin D insufficiency was observed (76, 71, 67, and 82%, at baseline, 1, 6, and 24 months, respectively), and plasma 25(OH)D concentrations were lower in AA compared to white patients (P < 0.05). Strong positive baseline and 1 month cross-sectional correlations between FAT and plasma 25(OH)D were observed, which remained after adjustment for age and race subgroup (β = 0.76 and 0.61, respectively, P = 0.02). In conclusion, 25(OH)D concentrations increased temporarily and then decreased during the 24 months following RYGB. The acute increase and the positive associations observed between adipose tissue mass and systemic 25(OH)D concentrations suggest storage in adipose tissue and release during weight loss</blockquote>.
  
 +The study discussed here: [[http://marshallprotocol.com/view_topic.php?id=8252&forum_id=39&jump_to=257136#p257136|Tea and coffee consumption in relation to vitamin D and calcium levels in Saudi adolescents]] provides additional evidence that non-supplemented populations have low 25D. 330 Saudi adolescents with average 25D levels of 8-10ng/mL.
 ===== References ===== ===== References =====
home/tests/25d.txt · Last modified: 09.14.2022 by 127.0.0.1
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