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Why I don’t think that this is a legit theory anymore
Quote from wavygravygadzooks on November 2, 2021, 2:26 pmI don't see in that study a description of how the meat was sampled. Do you know how it was?
How did they select the muscle meat from the carcass? Where on the carcass did it come from? Was there a standard quantity of fat contained in the muscle for each sample? It seems like we have no idea how much fat was contained in the samples.
Liver is listed as 24% fat, 64% protein, 12% carbs. It definitely has fat in it, and probably more than numerous different cuts of muscle meat.
The reference [11] in the Egyptian/Japanese study describes the "extraction" method. I've attached the PDF of the article if you wish to read it. The identification of retinol uses "standards" from a company called Sigma Chemical, which may have subsequently merged with other firms. If you look into these techniques more, please report back to us.
There is no discussion of which muscles of the cattle were sampled. I doubt it would matter for the grass-finished cattle, which should have low intramuscular fat, i.e. low marbling.
You are right, there is some fat in liver, but it is considered a lean meat like muscle meat. In grams, this website says 100g of beef liver has 5g of fat and 29g of protein. Maybe you were giving percentages of calories?
https://www.eatthismuch.com/food/nutrition/beef-liver,2767/
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I think the results you brought up from the two studies you posted on retinol in cow muscle meat (~36 mcg/g & ~10 mcg/g) first of all are unreasonable. Secondly as you yourself pointed out, these animals where all given retinol supplements in their feed, even the controls.
The studies might just have made a mistake of using the wrong unit for their numbers since using the units "nutrition weight per 100 g" is a much much more common unit as some astute person remarked when this same Egyptian study was brought up in Dr. Smith's Love Your Liver network. Then those figures would make much more sense and seem to fit in with other known nutritional databases of something around 8 mcg/100 g of muscle meat. I don't think it is farfetched that the two studies made a mistake with their use of units.
I think it is farfetched that the studies show that muscle meat can contain more vitamin A (RAE I think) than even the known high vitamin A food of butter which on the low end contains 600 mcg/100 g. The cow muscle meat from the two mentioned studies is said to have a vitamin A concentration of 3600 mcg/100 g and 1000 mcg/100 g respectively.
Even if their results would be correct I would then start to wonder how sick might the cows in these two studies be in order to cause them to have really high levels of vitamin A in their muscle meat.
For good measure I will add a table of analyzed values for meat as a clumped up category measured both at spring (s) and autumn (a) with HPLC. The study is from 1989 and is called "Food Groups as the Source of Retinoids, Carotenoids and Vitamin A in Finland" by M. Heinonen. That table shows there was 12 mcg of vitamin A (RE) per 100 g of meat, no matter the season.
There was also a telling pie graph in the same study showing how the 1987 Finnish people ingested vitamin A from a few broad categories.
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Quote from David on November 2, 2021, 10:54 pmAI think the results you brought up from the two studies you posted on retinol in cow muscle meat (~36 mcg/g & ~10 mcg/g) first of all is unreasonable. Secondly as you yourself pointed out, these animals where all given retinol supplements in their feed, even the controls.
The studies might just have made a mistake of using the wrong unit for their numbers since using the units "nutrition weight per 100 g" is a much much more common unit as some astute person remarked when this same Egyptian study was brought up in Dr. Smith's Love Your Liver network. Then those figures would make much more sense and seem to fit in with other known nutritional databases of something around 8 mcg/100 g of muscle meat. I don't think it is farfetched that the two studies made a mistake with their use of units.
I think it is farfetched that the studies show that muscle meat can contain more vitamin A (RAE I think) than even the known high vitamin A food of butter which on the low end contains 600 mcg/100 g. The cow muscle meat from the two mentioned studies is said to have a vitamin A concentration of 3600 mcg/100 g and 1000 mcg/100 g respectively from their graphs.
Even if their results would be correct I would then start to wonder how sick might the cows in these two studies be in order to cause them to have really high levels of vitamin A in their muscle meat.
For good measure I will add a table of analyzed values for meat as a clumped up category measured both at spring (s) and autumn (a) with HPLC. The study is from 1989 and is called "Food Groups as the Source of Retinoids, Carotenoids and Vitamin A in Finland" by M. Heinonen. That table shows there was 12 mcg of vitamin A (RE) per 100 g of meat, no matter the season.
There was also a telling pie graph in the same study showing where the 1988-1989 Finnish people ingested vitamin A from sorted into broad categories.
Good one ,
The claim the muscle meat has ton of Vitamin A is crap .
More off topic.
A table showing the seasonal variation of vitamin A (RE) in chicken, beef and pork liver from the same 1989 study as mentioned above. On page 5 Heinonen brings up the extremely high values of vitamin A in pork liver and how it probably related to what they are fed:
"The most probable reason for this high amount lies in the feeding practices of animals: pigs are fed overdoses of vitamin A."
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Quote from David on November 2, 2021, 10:54 pmI think the results you brought up from the two studies you posted on retinol in cow muscle meat (~36 mcg/g & ~10 mcg/g) first of all is unreasonable. Secondly as you yourself pointed out, these animals where all given retinol supplements in their feed, even the controls.
The studies might just have made a mistake of using the wrong unit for their numbers since using the units "nutrition weight per 100 g" is a much much more common unit as some astute person remarked when this same Egyptian study was brought up in Dr. Smith's Love Your Liver network. Then those figures would make much more sense and seem to fit in with other known nutritional databases of something around 8 mcg/100 g of muscle meat. I don't think it is farfetched that the two studies made a mistake with their use of units.
The idea that the two latest studies publishing measuring retinol levels in beef are both getting the units messed up is pretty extreme. There is no connection between these authors that I can see and no reason this type of obvious mistake would be made by both sets of authors and that it would not be corrected by notices in the journals if the numbers were off by 100-fold.
The vitamin A supplements in the control group's rations were for only one of the two studies and the time path shows a tremendous decrease in retinol levels from month four to five of grain-finishing, which is why the Chinese study is relevant for a discussion of grass-finished beef. As an aside, many if not most grass-finished producers do supplement the cattle with vitamin A, although perhaps not in Grant's case as he knows the rancher personally.
Finally, the Egyptian/Japanese study, for example, used an extraction method published in 2003, so I don't think quoting a study from 1989 or a USDA database value for butter is relevant for discussing more recent data.
It is you who are making extraordinary claims with those two studies. Calculate the ratios of vitamin A in liver to vitamin A in muscle meat to see how insanely high the muscle meat values are. They could be correct but then I would argue that is because of them measuring sick animals.
The mean vitamin A liver/muscle meat-ratio from the 1989 study (which is much more well made study than the Egyptian study you brought up):
Beef liver vitamin A concentration (mean) = 27000 mcg/100 g
Muscle meat vitamin A concentration (mean) = 12 mcg/100 g
27000 / 12 = 2250
Please try to explain why the ratio in your two studies seem to deviate tremendously from this well-made 1989 study.
PS. I know the 1989 study use a combined category for different types of ordinary available muscle meats but these values does not deviate greatly from other values like the USDA, in contrast to your two studies vitamin A values for muscle meat.
Please try to explain why the ratio in your two studies seem to deviate tremendously from this well-made 1989 study.
Why is the 1989 study "well made" and the recent studies are not "well made"?
Could you calculate the vitamin A liver/muscle meat-ratio from those two studies you brought up and try to explain why those ratios are deviating so much from the one I calculated in the 1989 study?
After that I can post the whole 1989 study for you to read and compare for instance to the Egyptian study.
Quote from David on November 3, 2021, 6:35 amIt is you who are making extraordinary claims with those two studies. Calculate the ratios of vitamin A in liver to vitamin A in muscle meat to see how insanely high the muscle meat values are. They could be correct but then I would argue that is because of them measuring sick animals.
The mean vitamin A liver/muscle meat-ratio from the 1989 study (which is much more well made study than the Egyptian study you brought up):
Beef liver vitamin A concentration (mean) = 27000 mcg/100 g
Muscle meat vitamin A concentration (mean) = 12 mcg/100 g
27000 / 12 = 2250
Please try to explain why the ratio in your two studies seem to deviate tremendously from this well-made 1989 study.
PS. I know the 1989 study use a combined category for different types of ordinary available muscle meats but these values does not deviate greatly from other values like the USDA, in contrast to your two studies vitamin A values for muscle meat.
David, I'm sorry, but it's unscientific to talk about the ratio of VA content in the liver and meat. This ratio is not used anywhere (I haven't seen).
On the other hand, the vitamin A content in the liver of grain-fed liver corresponds to what I see in the databases. So I trust this research.
Retinoicon, I'm with you. I suspect that "organic grass-fed beef" is just a deception of people who do not know about VA-toxicity, but are trying to lead a healthy lifestyle.
I think it is logical that grass-fed meat will contain more retinol than grain. Carotenoids are stored in muscle tissue and will be locally converted into retinol.
Also, grass butter certainly will contain much more retinol than grain.
On the other hand, Grant somehow managed to deplete VA by consuming bison meat. There may be several factors involved:
1) I think Grant's bison have NEVER received vitamin A supplements (am I right, Grant?). 2) Grant eats the most fat-free pieces 3) I think that different types of grass may contain different amounts of carotenoids. Anyway, we would have to measure the VA content in the meat that Grant directly eats. In the meantime, Grant, I agree that you'd be better off sticking to lean grain-fattening chunks.
Hi @daniil,
RE: 1) I think Grant's bison have NEVER received vitamin A supplements (am I right, Grant?).
Yes, that's correct. The rancher that raises them here does not even feed them supplemental grass / hay. Not even in the winter.
They are as 100% natural as you can get. These animals are also not sent to feed-lots for "finishing" aka fattening, as most beef cattle are here in Alberta.
BTW, I didn't go looking for that ultra-natural bison, I just happened on to it by chance. But, I still think beef in reasonable amounts is quite safe too.
RE: 2) Grant eats the most fat-free pieces
Yes, true.
I think that pie chart posted by @david is quite interesting. There was a discussion here a while ago where I think it was @michele that said that she made a big turn around in her health on a mostly fruit diet. It looks like what an all meat and an all fruit diet have in common is they are both really low vA intake.