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Why I don’t think that this is a legit theory anymore
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.
You don't understand the methods either! No one on this forum does. You write as if the results you prefer from the 1980s are correct until someone on this group does an immense amount of studying and convinces you otherwise. Your preferred results are certainly no more justified as some sort of default position than mine are, and possibly less justified as they use older methods that were possibly supplanted for a good reason.
Quote from wavygravygadzooks on November 4, 2021, 2:19 pmNot 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.
>but the amount reported in the liver itself in the newer study is nearly 8x greater, which is quite significant.
Either you're looking at the vitamin A content in the liver of grass-fed instead of grain, or I don't understand which database you're looking at. The vitamin A content in the liver of grain fattening (~5000 mcg/100g) in Egypt study corresponds to what I see in the database that I use.
Quote from David on November 5, 2021, 4:45 amJeremy, 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 PDFThe 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 paywallI 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) when find this amount of feed concentrate per day and cow:
381 kg * 1%/day = 3.81 kg/day of feed concentrateIn 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 premixUnder Table 1 in the 2015 Chinese, 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 /dayThis can be seen in the their own study in Figure 3 since all the values drop at almost the same time from 90 days to 120 days and also 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.
>This is since they probably stopped poisoning all of the animals with the previously described fed concentrate.
LoL. I was interested in what animals are fed in Russia. The standard premix for cows contains 2,500,000 IU per kg, for pigs 2,000,000, and for chickens 1 000 000 + 50 gram of beta-carotene. They there took pity on the bulls.
Quote from David on November 5, 2021, 5:09 amI 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: https://www.scopus.com/authid/detail.uri?authorId=7005338538
I will ask you to explain why the content of beta-carotene in meat in the table you have given, is several times higher than the content of retinol, which, in my opinion, is nonsense.
Also a little strange is the low (~1900 mcg /100 grams) vitamin A content in the liver of cows.
And I will ask you to publish links to the studies you cite. Because, as everyone knows on this forum, I have some problems with access to research for a number of reasons. As I understand it, we are talking about two studies from 1988-1989.
In general, given that the amounts of retinol vary very much, and beta-carotene is the same, I think the problem or is in the determination methods(although they seem to use the same methods), or someone made a stupid mistake in calculations. I can't find anything. @johannes2 please help us to to decide an important issue
@jeremy I remember that you have contacted the authors of the Egyptian study. Could you ask them why the numbers vary so much?
Quote from Даниил on November 5, 2021, 8:02 pmIn general, given that the amounts of retinol vary very much, and beta-carotene is the same, I think the problem or is in the determination methods(although they seem to use the same methods), or someone made a stupid mistake in calculations. I can't find anything. @johannes2 please help us to to decide an important issue
@jeremy I remember that you have contacted the authors of the Egyptian study. Could you ask them why the numbers vary so much?
I never got a reply back from the one author I contacted, although he might have been reluctant to respond to someone concerned about high vitamin A in meat. Can you repeat what you mean by "why the numbers vary so much"?
Funny that you made a conversion error from the value of beef liver in the 1988 study I posted!
I myself do conversion errors all the time which is why I always try to double check conversions. But in this case you could just have checked Table 2 in the 1988 study, co-authored by Heinonen, that clearly says vitamin A (RE) in beef liver was 20 000 mcg/100 g not ~1900 mcg of all-trans-retinol/100 g.
If you wonder what the liver/muscle meat-ratio between vitamin A (RE) is in the 1988 study, and I even choose beef brisket as the muscle meat since it has the highest vitamin A concentration (RE/100g):
Beef liver: 20 000 mcg/100 g
Beef brisket (bone less): 26 mcg/100 g
Beef liver/beef brisket-ratio: 20 000 / 26 = 769
Which is far off the ratio of around 10 in the 2015 Chinese study and the 2015 Egyptian study.
@daniil Unless you really bring something meaningful to the discussion I won't reply to you any further.
PS. I am concerned about the high retinol number of the 2015 studies and wonder how prevalent the supplemental vitamin A poisoning is of farm animals. It is truly disturbing but I believe it is not in any shape or form an inherent problem with the animals or what they natural eat. The older studies shows us that a better way is possible even if the 2015 Chinese study and the 2015 Egyptian study could be shown to be applicable to meat that is made for human consumption, not experiment animals.
Think of the 1925 Wolbach and Howe study, which segmenting vitamin A as vitamin, which for sure just poisoned the test animals as Grant Genereux has brought up many times.
Source for the 1925 Wolbach and Howe study: https://pubmed.ncbi.nlm.nih.gov/19869087/
Quote from Retinoicon on November 5, 2021, 8:12 pmQuote from Даниил on November 5, 2021, 8:02 pmIn general, given that the amounts of retinol vary very much, and beta-carotene is the same, I think the problem or is in the determination methods(although they seem to use the same methods), or someone made a stupid mistake in calculations. I can't find anything. @johannes2 please help us to to decide an important issue
@jeremy I remember that you have contacted the authors of the Egyptian study. Could you ask them why the numbers vary so much?
I never got a reply back from the one author I contacted, although he might have been reluctant to respond to someone concerned about high vitamin A in meat. Can you repeat what you mean by "why the numbers vary so much"?
I'm talking about "the ratio of retinol in the liver and muscles"