Quote from Dr. Garrett Smith on November 7, 2018, 10:18 pm

Giving blood may be part of the solution to both hypervitaminosis A and iron overload at the same time (because they may be much more connected than anyone previously thought):

Circulating Retinol-Binding Protein-4 Concentration Might Reflect Insulin Resistance–Associated Iron Overload

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2453621/
"OBJECTIVES—The mechanisms behind the association between retinol-binding protein-4 (RBP4) and insulin resistance are not well understood. An interaction between iron and vitamin A status, of which RBP4 is a surrogate, has long been recognized. We hypothesized that iron-associated insulin resistance could be behind the impaired insulin action caused by RBP4.

RESEARCH DESIGN AND METHODS—Serum ferritin and RBP4 concentration and insulin resistance were evaluated in a sample of middle-aged men (n = 132) and in a replication independent study. Serum RBP4 was also studied before and after iron depletion in patients with type 2 diabetes. Finally, the effect of iron on RBP4 release was evaluated in vitro in adipose tissue.

RESULTS—A positive correlation between circulating RBP4 and log serum ferritin was observed in both independent studies. Serum RBP4 concentration was higher in men than women in parallel to increased ferritin levels. On multiple regression analyses to predict serum RBP4, log serum ferritin contributed significantly to RBP4 variance after controlling for BMI, age, and homeostasis model assessment value. Serum RBP4 concentration decreased after iron depletion in type 2 diabetic patients. The iron donor lactoferrin led to increased dose-dependent adipose tissue release of RBP4 and increased RBP4 expression, while apotransferrin and deferoxamine led to decreased RBP4 release.

CONCLUSIONS—The relationship between circulating RBP4 and iron stores, both cross-sectional and after iron depletion, and in vitro findings suggest that iron could play a role in the RBP4–insulin resistance relationship."

Translation:  Higher RBP = higher retinol (aka Poison/"Vitamin A") = more iron overload.  Giving blood helps to lower BOTH Poison/"Vitamin A" AND iron overload.

The grand question for me then becomes...just how much of society's iron overload is being CAUSED by Poison/"Vitamin A"???

Then...if we will (or already have) linked Poison/"Vitamin A" toxicity to fatty liver and insulin resistance in other threads, and this next study shows that giving blood helps to normalize those problems as well...is that pointing towards the depletion of Poison/"Vitamin A" through blood giving as a solution there too?

Venesection for non-alcoholic fatty liver disease unresponsive to lifestyle counselling—a propensity score-adjusted observational study

https://academic.oup.com/qjmed/article/104/2/141/1578674
"In conclusion, iron depletion by venesection favours the normalization of raised aminotransferases and insulin sensitivity in non-haemochromatosis patients with NAFLD unresponsive to lifestyle counselling, as established by a propensity score-adjusted retrospective analysis of a prospectively-collected large database. The procedure is well tolerated and may be more extensively proposed and investigated in the clinical setting."

Between the above two studies, we can combine them to infer:
Giving blood...lowers both iron overload and retinol/RBP...which then lowers liver enzymes and improves insulin sensitivity.  Sounds good to me!

All that said...Poison/"Vitamin A" toxicity is also shown in the literature to cause anemia (low red blood cells, poor blood, basically).  If someone is anemic, they shouldn't be giving blood.  This is why working with a practitioner who understands the angles on these situations is so important.  I might know a guy... ?