Obesity Decreases Hepatic 25‐Hydroxylase Activity Causing Low Serum 25‐Hydroxyvitamin D
Journal of Bone Mineral Research https://doi.org/10.1002/jbmr.3686
Jeffrey D Roizen Caela Long Alex Casella Lauren O'Lear Ilana Caplan Meizan Lai Issac Sasson Ravinder Singh Andrew J Makowski … See all authors
- Vitamin D insufficiency was 3.7 X more likely if CYP2R1 gene variation– June 2014
- Search Vitamin D Life for CYP2R1 895 items in Vitamin D Life as of June 2019
- CYP2R1 (vitamin D 25-hydroxylase ) semiactivates vitamin D in many places in the body
- Note: More Vitamin D activation appears to take place in skin than liver
Genetics category listing contains the following
see also
384 articles in Vitamin D Receptor 141 articles in Vitamin D Binding Protein = GC 35 articles in CYP27B1 - Topical Vitamin D
- Nanoemulsion Vitamin D may be a substantially better form
- Getting Vitamin D into your body
Vitamin D blood test misses a lot
- Snapshot of the literature by Vitamin D Life 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 blood test results (> 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 Vitamin D Life took action with clues #3&4
Overview Obesity and Vitamin D contains the following summary
- FACT: People who are obese have less vitamin D in their blood
- FACT: Obese need a higher dose of vitamin D to get to the same level of vit D
- FACT: When obese people lose weight the vitamin D level in their blood increases
- FACT: Adding Calcium, perhaps in the form of fortified milk, often reduces weight
- FACT: 153 trials for vitamin D intervention of obesity as of Sept 2020
- FACT: Less weight gain by senior women with > 30 ng of vitamin D
- FACT: Dieters lost additional 5 lbs if vitamin D supplementation got them above 32 ng - RCT
- FACT: Obese lost 3X more weight by adding $10 of Vitamin D
- FACT: Those with darker skins were more likely to be obese Sept 2014
- OBSERVATION: Many mammals had evolved to add fat and vitamin D in the autumn
- and lose both in the Spring - unfortunately humans have forgotten to lose the fat in the Spring
- SUGGESTION: Probably need more than 4,000 IU to lose weight if very low on vitamin D due to
risk factors such as overweight, age, dark skin, live far from equator,shut-in, etc. - Obesity category has
352 items - Normal weight Obese (50 ng = 125 nanomole)
Report on this study
/How does a high-fat diet influence vitamin D metabolism?
"Obesity reduces the ability of the liver to convert vitamin D into calcidiol"Download the PDF from Sci-Hub via Vitamin D Life
Normal vitamin D homeostasis is critical for optimal health; nevertheless, vitamin D deficiency is a worldwide public health problem. Vitamin D insufficiency is most commonly due to inadequate cutaneous synthesis of cholecalciferol and/or insufficient intake of vitamin D, but can also arise as a consequence of pathological states such as obesity. Serum concentrations of 25(OH)D (calcidiol) are low in obesity, and fail to increase appropriately after vitamin D supplementation.
Although sequestration of vitamin D in adipose tissues or dilution of ingested or cutaneously synthesized vitamin D in the large fat mass of obese patients has been proposed to explain these findings, here we investigate the alternative mechanism that reduced capacity to convert parent vitamin D to 25(OH)D due to decreased expression of CYP2R1, the principal hepatic vitamin D 25‐hydroxylase.
To test this hypothesis, we isolated livers from female mice of 6 to 24 weeks of age, weaned onto either a normal chow diet or a high‐fat diet, and determined the abundance of Cyp2r1 mRNA using digital droplet‐quantitative PCR. We observed a significant (p < 0.001) decrease in Cyp2r1 mRNA in the liver of high‐fat diet–fed mice relative to lean‐chow–fed female mice. Moreover, there was a significant (p < 0.01) relationship between levels of Cyp2r1 mRNA and serum 25(OH)D concentrations as well as between Cyp2R1 mRNA and the ratio of circulating 25(OH)D3 to cholecalciferol (p < 0.0001).
Using linear regression we determined a curve with 25(OH)D3/cholecalciferol versus normalized Cyp2R1 mRNA abundance with an R2 value of 0.85. Finally, we performed ex vivo activity assays of isolated livers and found that obese mice generated significantly less 25(OH)D3 than lean mice (p < 0.05). Our findings indicate that expression of CYP2R1 is reduced in obesity and accounts in part for the decreased circulating 25(OH)D.Obesity cut semi-activation of Vitamin D in half (mice) – Jan 2019Printer Friendly PDF this page! Follow this page for updates1061 visitors, last modified 17 Jun, 2019, This page is in the following categories (# of items in each category)