How Inferior Is Beta-carotene Compared To Vitamin A From Meat Sources?

Discussion in 'Vitamins' started by AretnaP, Aug 30, 2017.

  1. AretnaP

    AretnaP Member

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  2. Tarmander

    Tarmander Member

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    Conversion of beta carotene to vitamin A is dependent on an enzyme that is higher and lower in different peoples. So yes, beta carotene has less activity then straight vitamin A. Beta Carotene is also unsaturated.
     
  3. Sucrates

    Sucrates Member

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    I think the more beta-carotene in the diet, the more it becomes in opposition to vitamin A.

    https://www.sciencedaily.com/releases/2012/05/120501134414.htm

    "certain molecules that derive from beta-carotene have an opposite effect in the body: They actually block some actions of vitamin A, which is critical to human vision, bone and skin health, metabolism and immune function."
     
  4. Wagner83

    Wagner83 Member

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    So we shouldn't eat melons, mangoes or peaches? No way!
     
  5. Westside PUFAs

    Westside PUFAs Member

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    Once it's converted, it's vitamin A so to say it isn't nearly as effective doesn't make sense. It's the conversion is some people that may not be effective. GMO Golden Rice was engineered to have carotene to help poor people who have no access to anything with carotene, never mind preformed retinol, get A.

    Also, the preformed retinol from liver consumed can be toxic if consumed too often which is why Peat says to limit liver intake, among it's other negative properties like it's amino acids. Liver is the only food source that can cause toxicity of A. Egg yolks and butter have tiny amounts of vitamin A.

    "they can take care of a lot of carotene.."



    Ha. BC haters are inconsistent.
     
  6. Such_Saturation

    Such_Saturation Member

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    Extremely small amount gets converted unless you're deficient.
     
  7. DaveFoster

    DaveFoster Member

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  8. OP
    AretnaP

    AretnaP Member

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    This is also what I was talking about, I just didn't word it well. The conversion of BC into vit A.
     
  9. Ella

    Ella Member

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    It is individual specific. If your are hypothyroid, low metabolism then you will be less efficient at converting BC to retinol and BC is antagonist to retinol. Retinol is also an unsaturated molecule (which is why Ray says too much can interfere with thyroid function) but BC is a longer unsaturated molecule which is cleaved to form shorter unsaturated molecule of retinol.

    The conversion of BC is not an efficient conversion to begin with regardless of whether you are hypothyroid or not.

    Vitamin A Toxicity Develops when binding proteins are swamped
    Free vitamin A damages cells and toxicity is a real possibility Preformed vitamin A from animal sources come with its transport molecule unless supplemented; fortified foods; supplements and children are most vulnerable.

    Yes a real possibility exists in eating too much liver. You need to titrate to your specific needs. I thought I needed less once every ten days but found out I do better with more. Reason may be because I reduced foods high in beta carotene. I am still trying to work this out.

    You will have warning signs that you are overdoing liver or Vitamin A if you start getting headaches that were never there before and bone pain. Also too much will interfere with calcium, Vitamin D, so it would be prudent to track these along with other fat soluble vitamins.

    Don't just assume, if its coming from natural sources, you can eat loads of it. Balance in everything we do. I remember from my own research way back that there was a case of twin boys where one died from eating too much liver. I don't have the case on hand to post.

    Vitamin A (retinol) Safety - Mayo Clinic

    It is of interest though that McDougall is not concerned about getting preformed retinol and his followers must be converting BC efficiently to retinol. But if we remove those foods that are rich in BC then it is important to include preformed retinol rich foods in the diet. BC will not convert to retinol if there is sufficient stores of retinol. So I don't think it would be a good idea to have loads of retinol with lots of BC rich foods. Tricky I know. Retinol because it is fat soluble and stored in tissues; the Goldilocks Principle of "Just Right" would be prudent.

    Ray talks about really high doses when it comes to acne. These doses have been used in third world countries but the population is also subject to low protein and zinc status.

    [The problem of a high content of vitamin A in the liver of calves, cattle, sheep and swine for the consumer. Amount of accumulation and mechanism ... - PubMed - NCBI

    If you are buying supermarket meats, then these animals have been supplemented with vitamin A and in monogastric chicken's and pig's liver, vitamin A will be higher than found in ruminant animals cows and sheep. Vitamin A is acted on by gut organisms and reduced. So vitamin A is tricky when eating liver because you need to take into account whether the animal has also been subjected to supplemental Vitamin A or not. It really does my head in and if retinol is such a big issue for toxicity, then is it not time we had reliable testing for it. Easy to get garden variety Vitamin D tested and it is advocated for everyone to get tested but not so with retinol??? Should we be advocating in having retinol included on the nutritional label of store bought liver??

    [The problem of a high content of vitamin A in the liver of calves, cattle, sheep and swine for the consumer. Amount of accumulation and mechanism ... - PubMed - NCBI

    HYPERVITAMINOSIS A: A REVIEW

    I raised my kids on raw liver juice and haven't kill them yet. Only in the winter though as summer we have lots of fruits and vegetables. Build up the Vitamin D in the summer for winter and buildup Vitamin A in winter to see you through the rest of the year. I am still working on optimisation and you will know retinol is low if you have problems driving in the night or seeing in the dark. I would never supplement though unless there are serious malabsorption issues like Celiac's and pancreatitis. Retinol is extremely important for the gut lining so it is one vitamin you want to get right.
     
  10. wintagal

    wintagal Member

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    Hypothyroid people can't convert beta-carotene to Vitamin A. I had a friend who turned yellow from eating carrot salad. Now I know that she was probably hypothyroid. My nails were yellowish (as if I smoked) before I started taking thyroid. Probably from beta-carotene in food.
     
  11. JackHanma

    JackHanma Member

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    B12 is needed for the conversion. I have heard numbers as low as 5% is converted to vitamin a.
    Otherwise vitamin a needs to be rationed properly with vitamin d.
    Carotenemia & Hypothyroidism – Functional Performance Systems (FPS)

    Ray used to take up to 100 000 units of actual vitamin a and not beta carotene:

    "For several years, when I had an extremely high metabolic rate, I needed 100,000 units per day during sunny weather to prevent acne and ingrown whiskers, but when I moved to a cloudy climate, suddenly that much was too much, and suppressed my thyroid. The average person is likely to be hypothyroid, and to need only 5,000 units per day. Avoiding large amounts of carotene, and getting plenty of vitamin B12 to be able to convert any carotene that’s in your food, helps to use vitamin A efficiently."

    I think one of the other sites says he was taking 11 000 units of vitamin d with it. More sunlight/vitamin d more vitamin a; less sunlight, less vitamin a, as too much vitamin a is anti-thyroid.
     
  12. Ella

    Ella Member

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    Plenty of Vitamin B12 is crucial which is provided if you eat liver which also contains loads of retinol. Sun exposure is likely to diminish levels of retinol, however I tend to reduce my consumption of liver during the summer months because I tend to eat more BC rich foods. In the summer months, thyroid function is also likely to be functioning more optimally compared to the stressful cold months. I would expect the conversion of BC to retinol to be more favourable. I hate it when I have to guess :( Need a simply way to test to know for sure. You would think in 2017 we could do this cheaply with our iphones!!! Even testing B12 is not so straight forward. I guess orange palms and soles of feet is simple enough :)
     
  13. Waynish

    Waynish Member

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    Any updates on this topic?
     
  14. What-a-Riot

    What-a-Riot Member

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    can anyone point me to any evidence that b12 is involved in converting carotene to useable vitamin A?
     
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