Vitamin D binding protein is lower in infertile patients compared to fertile controls: a case control study
Fertility Research and Practice20173:14, https://doi.org/10.1186/s40738-017-0042-0
Jason Franasiak, Sue Shapses, Wei Sun, Richard Scott and Xiangbing Wang
standard test, no difference
|Free 25OHD (pg/mL)||6.3 *||4.3|
|Bioavailable 25OHD (ng/mL)||3||2|
- P < 0.01 = statistically significant
Vitamin D binding protein(GC) and the Vitamin D Receptors (VDR) are two of the genes which restrict how much Vitamin D actually gets to cells . For both gene problems an easy solution (improved fertility in this case) is to just increase the amount of vitamin D consumed.
Note: gene problems in the male can also lead to infertility of the couple
- Assisted Reproduction – 5 studies concluded vitamin D repletion helps – Review March 2015
- Fertility and Sperm category listing has
106 items along with related searches
Genetics category listing contains the following
261 articles in the Genetics category
366 articles in Vitamin D Receptor 138 articles in Vitamin D Binding Protein = GC 32 articles in CYP27B1
Vitamin D blood test misses a lot
- Snapshot of the literature by VitaminDWiki as of early 2019
- Vitamin D from coming from tissues (vs blood) was speculated to be 50% in 2014, and by 2017 was speculated to be 90%
- Note: Good results from a blood test (> 40 ng) does not mean that a good amount of Vitamin D actually gets to cells
- A Vitamin D test in cells rather than blood was feasible (2017 personal communication)
- Commercially available 2019
However test results would vary in each tissue due to multiple genes
- Good clues that Vitamin D is being restricted from getting to the cells
1) A vitamin D-related health problem runs in the family
especially if it is one of 51+ diseases related to Vitamin D Receptor
2) Slightly increasing Vitamin D show benefits (even if conventional Vitamin D test shows an increase)
3) Vitamin D Receptor test (<$30) scores are difficult to understand in 2016
easier to understand the VDR 23andMe test results analyzed by FoundMyFitness in 2018
4) Back Pain
probably want at least 2 clues before taking adding vitamin D, Omega-3, Magnesium, Resveratrol, etc
The founder of VitaminDWiki took action with clues #3&4
The importance of vitamin D in general health as well as in human reproductive success has been an area of focus. A better understanding of vitamin D metabolism, particularly vitamin D binding protein, is important when elucidating this relationship.
This case control trial seeks to characterize vitamin D metabolism in infertile patients undergoing natural cycle IVF as compared to normally cycling premenopausal women with proven fertility matched for age and body mass index (BMI). A total of 68 subjects were examined; 39 were infertile premenopausal women and 29 were regularly cycling fertile controls. Their 25-hydroxy vitamin D (25OHD), vitamin D binding protein (DBP), and albumin were measured and free and bioavailable 25OHD calculated. Between group comparisons were conducted with an unpaired t-test. A stepwise regression using age, BMI, 25OHD, estradiol & albumin in the model were used to determine predictors of DBP.
Age, BMI, and total 25OHD did not differ between the two groups. However, vitamin D binding protein, free and bioavailable vitamin D were significantly different in the infertile patients as compared to the regularly cycling fertile controls (p < 0.01). Stepwise Regression using age, BMI, 25OHD, estradiol & albumin in the model showed that only albumin was a predictor of DBP (β-coefficient − 0.310; p = 0.01).
The implications of lower vitamin D binding protein associated with infertility is not clear from this pilot study, and requires further study.