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Conventional beef vs grassfed beef
Is your bison or beef grain-fed or grass-fed? Thanks.
I seem to remember Grant writing that the bison was exclusively grass fed.
Hi @fred,
I buy the bison directly from the rancher, and the animals are naturally grass pastured only with no supplemental feed.
With for the beef, I'm not sure. I just buy regular (non organic) beef and I assume it is grain finished. But, there's a difference in what feed lots use for "grain" finished. I'm my understanding of it here in Alberta the grain is mostly wheat, whereas in some USA feed lots they use corn.
Quote from Moebius on May 26, 2021, 10:07 amI seem to remember Grant writing that the bison was exclusively grass fed.
It is my understanding that cattle is especially bad at converting/cleaving beta-carotene. So grass fed cattle would accumulate a lot more beta-carotene than grass fed anything else. This paper compared VA content in ungulates muscle and livers. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4785134/
"Concerning the total carotenoid contents in the tissues of the examined animals, the values follow the same trend as the β-carotene contents in these tissues. Muscle had lower concentrations compared with the liver (Fig. 2). Cattle and horse had the highest content of carotenoids in both examined tissues followed by buffalo and finally sheep and goats. Rats had very low concentrations compared with ungulates, which indicates that rodents have a different behavior in the accumulation of carotenoids."
"The aim of this study was to estimate total carotenoids, β-carotene and retinol concentrations in the livers and muscles of some ungulates (cattle, buffalo, sheep, goats and horses) in comparison with the Wistar rats as a control. Cattle and horses had the highest contents of total carotenoids and β-carotene. Unexpectedly, sheep was the highest accumulator of retinol with a mean concentration of 203 ± 23.34 µg/g, while the least accumulator was buffalo, having a mean value of 58.28 ± 13.77 µg/g. Livers had higher contents of the examined phytochemicals than muscles. Consumption of these tissues may provide human with some needs from these important phytochemicals, though ingestion of livers, especially that of the sheep, is not advisable for the pregnant women."
Beta-carotene content chart: https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/tileshop_pmc_inline.html?title=Click%20on%20image%20to%20zoom&p=PMC3&id=4785134_jvms-78-351-g001.jpg
Total carotenoid chart: https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/tileshop_pmc_inline.html?title=Click%20on%20image%20to%20zoom&p=PMC3&id=4785134_jvms-78-351-g002.jpg
Retinol content chart: https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/tileshop_pmc_inline.html?title=Click%20on%20image%20to%20zoom&p=PMC3&id=4785134_jvms-78-351-g003.jpg
According to this information it seems like grainfed cattle is the lowest in all forms of VA, then buffalo is the second best (I think all buffalo is grass fed so this is grass fed buffalo), then goat, then lamb, and finally grass fed cattle seems to be the worst.
This is very interesting. I gave up high vitamin A foods but am still on a carnivore diet with grass fed beef, fat, and marrow. Even switching to lamb might be an improvement.
Garrett Smith talks a lot about glyphosate. I imagine the wheat and corn being fed to grain finished cattle has glyophosate all over it. If so, it would be counterproductive to switch to grain finished beef.
Quote from Retinoicon on May 26, 2021, 5:07 pm
This is very interesting. I gave up high vitamin A foods but am still on a carnivore diet with grass fed beef, fat, and marrow. Even switching to lamb might be an improvement.
Garrett Smith talks a lot about glyphosate. I imagine the wheat and corn being fed to grain finished cattle has glyophosate all over it. If so, it would be counterproductive to switch to grain finished beef.
Maybe organic grain fed beef is the best option? Glyphosate is very toxic but I doubt it's as big of a problem as Garrett says
I looked more at the study. You have to look at the vertical axis of each of the three charts. The scale of retinol goes from 0 to 300 mcg/g while the scale of the figures for beta carotene and total carotenoids go from 0 to 9 mcg/g. So the beta carotene and total carotenoids in ruminant muscle meats and livers are pretty irrelevant compared to the retinol content.
Buffalo and grass fed cattle look to be about 10 mcg/g of retinol in muscle meat in Figure 3. So if you eat a lean 16 oz steak of buffalo or grass fed beef, you are getting 453 grams of meat, which equates to 4530 mcg of retinol. Meanwhile, the RDA for vitamin A in 900 mcg of retinol. So this grass fed beef or buffalo steak is getting you 4530/900 = 5.03 times the RDA!!! And this is without any fat at all if we assume the paper is only measuring lean tissues.
This is shocking. I don't see Garrett Smith recommending people avoid grass fed beef. Something is not right with these numbers.
Quote from Retinoicon on May 26, 2021, 5:30 pm
I looked more at the study. You have to look at the vertical axis of each of the three charts. The scale of retinol goes from 0 to 300 mcg/g while the scale of the figures for beta carotene and total carotenoids go from 0 to 9 mcg/g. So the beta carotene and total carotenoids in ruminant muscle meats and livers are pretty irrelevant compared to the retinol content.
Buffalo and grass fed cattle look to be about 10 mcg/g of retinol in muscle meat in Figure 3. So if you eat a lean 16 oz steak of buffalo or grass fed beef, you are getting 453 grams of meat, which equates to 4530 mcg of retinol. Meanwhile, the RDA for vitamin A in 900 mcg of retinol. So this grass fed beef or buffalo steak is getting you 4530/900 = 5.03 times the RDA!!! And this is without any fat at all if we assume the paper is only measuring lean tissues.
This is shocking. I don't see Garrett Smith recommending people avoid grass fed beef. Something is not right with these numbers.
All of these studies have quite different numbers but they all show the same relative values, that grass fed has way more VA than grainfed and I think that is the most important take away. I think probably the numbers on the first page of this page are more realistic. I think they use different methods of measuring it, how long has it been degraded, how has it been stored etc. are all factors. Most of the papers I've seen seem to suggest that 100g of beef has about 5-10 mcg per 100g, and grassfed probably has 5x to 10x that amount.
Quote from salt on May 26, 2021, 5:59 pmAll of these studies have quite different numbers but they all show the same relative values, that grass fed has way more VA than grainfed and I think that is the most important take away. I think probably the numbers on the first page of this page are more realistic. I think they use different methods of measuring it, how long has it been degraded, how has it been stored etc. are all factors. Most of the papers I've seen seem to suggest that 100g of beef has about 5-10 mcg per 100g, and grassfed probably has 5x to 10x that amount.
With respect, the numbers on the first page seem to be about beta carotene, not retinol. Beef is an animal food and the retinol content is far more important to folks like us than the beta carotene content, which is minimal compared to retinol. I am quite worried right now. I emailed one of the others of the Egyptian/Japanese study that measured retinol. Thanks for posting these studies, anyway.
Here's a study I just found that measures both beta carotene (Table 4) and retinol (Table 5) in the muscle of grain fed beef from China. Retinol is much more. But look at the control group (not supplemented with beta carotene) at 150 days, in Table 5. The level of muscle retinol is 3.8 mcg/g of tissue. That is less than the value of around 10 mcg/g for the grass fed cattle in the Japanese/Egyptian study but likely around the value for the grain fed cattle in that same Japanese/Egyptian study.
Maybe both grain fed and grass fed cattle have much more retinol than American food databases suggest.
The idea of supplementing cattle with beta carotene, the topic of the Chinese study, is also quite worrying. It does affect the level of retinol in the muscle.