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Why I don’t think that this is a legit theory anymore
I updated my previous comment (end of page 10) by adding a metaphor of an ABC powder fire extinguisher getting activated inside a car as one of my ideas as to why there might be high retinol concentration in the muscle meat as per the Egyptian 2015 study.
Could you yourself try to add something of substance to the discussion instead of just your conjectures?
Please stop commenting on my use of simple math in the form of division of two measured numbers that both have the same units, which is a ratio. In this case the ratio simply means how much higher is the vitamin A concentration in a liver sample compared to a muscle meat sample.
Not only is the ratio between Vitamin A in the liver and muscles radically different between these studies, but the amount reported in the liver itself in the newer study is nearly 8x greater, which is quite significant. Either this new methodology (if it is actually new) is revolutionary, or there is something suspect about the numbers, whether it's due to something particular about the animals, the sampling protocol, or a typographical error.
Regarding the "recovery" I had been asking about in previous posts, I just realized I was confusing the paper describing the original methods with the paper that used those cited methods for their own research. In the paper that describes the original methodology ("Improved simultaneous determination method of b-carotene and retinol with saponification in human serum and rat liver"), the term "recovery" is used several times without definition and there is a recovery value greater than 100%, which doesn't make sense to me. So if anyone has insight on that, I would be interested to hear.
I'm not going to respond to the somewhat vague allegations that there is something wrong with the two most recently published studies on retinol content in beef, except to say that we have two studies by different authors telling us a consistent story of high retinol content in beef muscle meat, particularly grass-finished beef muscle meat (and beef fed grains for only three or four instead of five months). This means that there needs to be something wrong with both studies to overturn the basic finding.
Of course there could be something wrong with any study, but random speculation isn't going to determine whether something is right or wrong.
@wavygravygadzooks, I intentionally didn't read the 2003 paper on new methods for extraction by saponification. I will never be an expert, but feel free to tell us what you learned.
Jeremy, how come you have been so infatuated with these two studies, as your main argument for them is that they are the most recent studies?
These are the two studies you brought up at page 9 of this thread and you can't seem to even try to explain why these two studies find extremely strange vitamin A concentrations in the liver and muscle meat:
The 2015 study called "β-carotene and retinol contents in the meat of herbivorous ungulates with a special
reference to their public health importance" by Wageh Sobhy DARWISH et. al. [The 2015 Egyptian study]
The 2015 Egyptian study downloadable as a PDF
The 2015 study called "Effects of feeding β-carotene on levels of β-carotene and vitamin A in blood and tissues of beef cattle and the effects on beef quality" by Qing Jin et. al. [The 2015 Chinese study]
The 2015 Chinese study that is behind a ScienceDirect paywall
I looked at the 2015 Chinese study and I think the idea of them being poisoned seems correct. Not a shocker that some scientist might unknowingly (or knowingly in toxicology studies) poison test animals.
Here is how they fed the animals:
"The concentrate feeding amount was controlled to 1% of the weight of each steer, which was adjusted once a month according to the steer's weight. After all cattle experienced 15 days of adaptation, they received 90 days of βC supplementation followed by 60 days of depletion (no supplementation). During the supplementation period, each steer was fed the same standard basic daily rations with the addition of 0, 600, 1200, or 1800 mg/day βC to the concentrate of each individual."
The animals are said to have had a mean weight of 381 kg at the start of the experiment:
"We randomly selected 120 continental crossbred (Simmental × local yellow cattle) steers (mean live weight of 381 ± 26.01 kg) from feedlots and assigned them to four groups."
Assuming no weight gain of the cows (to get a very conservative number) we then find this amount of feed concentrate given per day to every cow:
381 kg * 1%/day = 3.81 kg/day of feed concentrate
In Table 1 called Composition and nutrient contents of concentrates (air-dry basis), they list that 1% of the concentrate is made of a vitamin and mineral premix. The daily feeding of this premix is:
3.81 kg/day * 1% = 0.0381 kg/day of vitamin and mineral premix
Under Table 1 in the 2015 Chinese study, they write that the vitamin and mineral premix contains 1 250 000 IU of vitamin A supplement per kg of vitamin and mineral premix.
"The premix contained the following components per kg of concentrate: Vitamin A 1250 KIU [kilo-IU], vitamin D3 270 KIU, vitamin E 5 KIU, manganese 3060 mg, zinc 14,280 mg, iron 3170 mg, copper 3040 mg, selenium 100 mg, iodine 180 mg, cobalt 40 mg."
This means the steers (castrated male cows) in the study all got this amount of vitamin A per day during the supplementation phase which was 115 days in total [-15 to 0 days (adaption period) and 0-90 days (supplementation period)]
0.0381 kg/day * 1 250 000 IU vitamin A =47 625 IU vitamin A /day
This can be seen in the their own study in Figure 3 since all the groups values drop at almost the same time from 90 days to 120 days (also 120 to 150 days). This is seen as there is almost no significant difference between any of the groups getting different amounts of supplemental beta-carotene. This is since they probably stopped poisoning all of the animals with the previously described fed concentrate. See this part which I quoted earlier:
"During the supplementation period, each steer was fed the same standard basic daily rations with the addition of 0, 600, 1200, or 1800 mg/day βC to the concentrate of each individual."
Fig. 3. Changes in the amount of retinol stored in tissues over time. (A) Liver; (B) intestine; (C) muscle; (D) subcutaneous fat; (E) omental fat; (F) perirenal fat. Values are represented as mean ± SE, for 10 steers per group. a,b,cValues with different superscripts vary significantly (p < 0.05).
I think this is plenty enough for me to favor the real world 1989 study by M. Heinonen I posted earlier which analytical measured bought food items at least two times of a year instead of some scientists making bad experiments on innocent steers.
I had a quick look at the food scientist M. Heinonen from the 1989 study I posted and I found out she, Marina, had co-authored another interesting study showing the all-trans-retinol, 13-cis-retinol and beta-carotene concentrations in a wide variety of of meats. The name of this 1988 study is "Carotenoids and retinoids in finnish foods: Meat and meat products" by Ollilainen, Heinonen et. al. The study is behind a paywall but can be found a sci-hub using the DOI: https://doi.org/10.1016/0889-1575(88)90022-1
See Table 1 which I attached from the study showing among other all-trans-retinol, 13-cis-retinol and beta-carotene in many different types of meat.
The papers by Marina Heinonen between 1987-1990 was a part of her PhD, and since 2011 she is the professor of Food Safety (Chemical Food Safety) at the University of Helsinki. She has been part of the expert panel of EFSA (European Food Safety Authority) on NDA (Nutrition, Novel Foods and Food Allergens).
A link to a short description of: Marina Heinonen.
EDIT: Marina Heinonen has 16 543 citation on 182 of the scientific papers she has been a part of as per this link: https://www.scopus.com/authid/detail.uri?authorId=7005338538
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@ggenereux2014 I have been seeing news about all the countries (led by USA of course) signing an agreement to reduce methane (which they think comes from cows) by 30 percent in the next 9 years. I am very concerned that we won't be able to get our beef! I have beef 3 times a day!!!!
First, consistency is never proof positive of anything. Second, two data points don't make a trend, so the fact that you found two studies that appear to agree with one another is noteworthy, but does not in itself constitute proof of anything.
It's interesting that you are so confident that this "new" method of measuring Vitamin A content is more accurate and more relevant than any other methods, yet you haven't even attempted to read or understand those methods.
If the values reported in these newer studies are indeed accurate, then what is your explanation for the way they deviate so dramatically from previous measurements? And you can't just say "new and better methods" without explaining how those methods function, how they differ from previous methods, and why they are better. It seems to me you are making a huge assumption that new technology unequivocally leads to better research results, which is never a safe assumption. Some of the best science was conducted decades ago...new technology is no replacement for savvy researchers.
@david is providing some pretty compelling points and so far your response has basically just been that new studies are inevitably more reliable than old studies, which is entirely fallacious.
@wavygravygadzooks You don't have anything interesting to add on measuring vitamin A, either. You and @David seem to like the conclusions of studies published in the 1980s by a grad student from Finland but you both have said nothing interesting about the scientific process other than that you prefer her conclusions because they match your prior views, which presumably themselves come originally from studies published in the 1980s or the USDA database values, which I would imagine often date to the 1980s or earlier.
RESULTS derive from, and are entirely dependent on, METHODOLOGY. It is interesting to see that muscle meat might contain more Vitamin A than previously thought, based on the results from the papers you're citing, and that possibility definitely piques my interest, and we should certainly ask why the data are different from other results. But in order to judge the validity and applicability of the RESULTS, you must understand the validity and applicability of the METHODS . And since you have no grasp of the METHODS used for Vitamin A extraction in the papers you're citing, and how they compare to other methods, you have no basis to judge the validity and applicability of the RESULTS.
My wife's M.S. research was entirely based on new methods that were supposed to be an improvement over old methods, but her thesis work ended up being completely worthless because it turned out the "new and improved" methods she used were inappropriate for addressing the questions they were being used to answer.
Results are nearly meaningless if you don't understand the methods used to reach those results. In many ways, new methods are more suspect than older methods if older methods have a longer track record that vets their legitimacy and applicability.
Bottom line: if you want to strengthen your argument, you're going to need a better understanding of the methods. And I am not so much arguing against the results of these new papers as I am arguing for skepticism and asking why the results are so dramatically different from previous research.