Vitamin A content of grass fed meat
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Thought I’d look into the retinol content of grass fed meat. Here’s the study I found:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4785134/
They measured the retinol content of various grass fed meat(cattle, buffalo, horse, sheep, goat). I’m gonna focus on cattle as that has the most relevance.
Beef retinol content: ~0.01622 mg/g or 54.06 iu/g
-I found these numbers by looking at this chart (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4785134/table/tbl_001/?report=objectonly) and dividing by the EDI = 85.7g
With these numbers, I wanted to establish the retinol content for the leanest cut of beef I could find: trimmed eye of round steak. This puts it around 4%, so I will use 3% fat as my value to avoid rounding error.
This calculation will use the assumption that all retinol is stored in the fat of the meat. Since we do not know the fat percentage of the muscle meat used in this study, I looked at this ultrasound scanning of intramuscular fat
http://extension.msstate.edu/publications/ultrasound-scanning-beef-cattle-for-body-composition
which places the upper range of fat content at 10.13%. However, just for fun I will assume they used 30% fat muscle meat to match the fattiest beef you can get from the store.
So, under these assumptions this puts the lowest possible retinol content of grass fed beef at:
5.4 iu/g or ~2450 iu/lb
If they used muscle meat that was ~10% fat, which is a more likely situation, the lowest retinol grass feed beef would have:
16.2 iu/g or ~8158 iu/lb
Feel free to check my numbers or send other studies looking at this