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Thread: Spinach, Oxalates, Calcium, and Vitamin A toxicosis

  1. #1
    PBluejay2 Guest

    Default Spinach, Oxalates, Calcium, and Vitamin A toxicosis

    I fear this might cause some controversy because it contradicts some of our long-held assumptions/beliefs (the world is not flat?), but I've been questioning some of our "givens" (questioning minds never stop) and did some research in the USDA and other databases regarding a couple of nutrition issues. I found no where that the oxalates in spinach or any other food blocks the absortion of the calcium contained in any other food. I also tried to confirm that animals (humans included) have been known to get vitamin A toxicosis from vegetables and found nothing. To confirm or refute my findings, I emailed a Phd in nutrition. Below is our exchange:

    My inquiry:

    I rehabilitate squirrels, and certain issues about their diets have come up. My questions are

    1) Do the oxalates in spinach block calcium absorption from any other foods or only the calcium in the spinach itself?
    2) Can an animal (human even) get Vitamin A toxicosis from eating vegetables high in vitamin A? I read about some mountain climbers getting vitamin A toxicosis from eating a diet consisting primarily of bear liver (of all things), but veggies?

    Her response (my bold):

    Oxalates reduce the absorption of the minerals in the food itself (calcium and iron primarily) because they chemically bind the mineral in the food so it’s not absorbed. Other food sources without oxalates will not be affected.

    The active form of Vitamin A is found in animal products like liver… polar bear liver has the most but regular old beef liver has 6580 micrograms/3 oz and upper tolerable level (to avoid toxicity) is 3000. The RDA for humans is 700-900. The plant version is a precursor form of Beta Carotene. There is no possibility of toxicity with plant sources because the liver will not convert it fast enough to be toxic and the excess carotene is stored in the fat cells under the skin and causes the skin to become “orangy”.

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    Default Re: Spinach, Oxalates, Calcium, and Vitamin A toxicosis

    Oxalates can block the calcium in any food with which they are eaten. For example, if you drink tea with milk, the oxalates in the tea will block most of the calcium in the milk. If one were attempting to feed a mix of high-calcium/low-phosphorus vegetables, adding spinach to the bowl hardly seems the healthiest option. Even if there is only enough oxalate in spinach to block the amount of calcium in the spinach, there's still the phosphorus in the spinach, which would now have no calcium to bind with. I guess the point is, anything that blocks calcium hardly seems like the healthiest veggie possible with our MBD-prone critters. Plus, the concern about the formation of crystals or stones in the kidneys and bladder remains.

    As for vitamin A, first of all, vitamin overdoses in humans other than through oversupplementation are rare. In small animals however, there is more danger: they eat 10 times more food relative to their own body weight than a human. Picture eating 15 pounds of healthy foods per day and you might start to get those vitamin levels up there.

    However, my main concern with frank vitamin A toxicosis is, of course, with fortified foods and vitamin supplements designed for birds since they contain large amounts of vitamin A, and it's almost never the nontoxic, natural form (beta-carotene), but rather the much more toxic (and cheaper) retinoids.

    Although HHBs are made with mostly beta-carotene, other rodent blocks contain retinoids--often at very high doses. So the idea behind limiting high vitamin A veggies is simply to keep all the nutrients in balance, understanding that different brands of rodent block may be fed. And in any case, we certainly don't want our squirrels turning orange!

    That being said, the Healthy Diet is super-conservative, admittedly. And I'm sure some of the "rules" there could be broken without harm.
    Last edited by 4skwerlz; 02-02-2010 at 06:06 PM.
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  3. #3
    PBluejay2 Guest

    Default Re: Spinach, Oxalates, Calcium, and Vitamin A toxicosis

    Quote Originally Posted by 4skwerlz
    Oxalates will block the calcium in any food with which they are eaten. For example, if you drink tea with milk, the oxalates in the tea will block most of the calcium in the milk.

    Yes, I read what the nutritionist at the Mayo clinic said about milk and tea, and I can't speak to that (but I don't feed my squirrels either milk or tea), but I researched and asked specifially about the oxalates in vegetables blocking calcium absorption, and from what I could find (and was told), it blocks the absoption of the calcium in the vegetable itself, not the calcium in any other food. That's why spinach, for example, is high in calcium but only 5% (I think) of it is absorbed.

    I quote: "although spinach has a lot of calcium, it also contains a substance -- oxalic acid -- that binds up its calcium and prevents absorption of all but about 5 percent of it. However, the oxalic acid in spinach and foods like rhubarb does not interfere with absorption of calcium from other foods eaten at the same time."

    I looked on several databases to find concrete evidence to the contrary and consulted a Phd with 35 years of researching and teaching nutrition, but if you have evidence to the contrary, I'll present it to her.


    If one were attempting to feed a mix of high-calcium/low-phosphorus vegetables, adding spinach to the bowl would certainly work against that.

    I don't understand this. Spinach has a 2.0 to 1 Calcium to Phosphorus ratio (99 mg Ca to 49 mg Phos per 100 gms). And if the oxalic acid affects only the calcium in the spinach, then for every 100 grams of spinach, the squirrels would still be getting 5 mg of calcium to the good.

    I suppose one could advise folks to feed spinach as a separate meal, but that starts to get complicated. Plus, the concern about the formation of crystals or stones in the kidneys and bladder remains.

    Yes, too much oxalate can cause kidney stones and crystals in the urine, but so can too much calcium. From what I've read, it's often the result of a Ph imbalance. Oxalic acid is an acid (obviously) and calcium is a base.

    As for vitamin A, first of all, vitamin overdoses in humans other than through oversupplementation are rare. In small animals however, there is more danger: they eat 10 times more food relative to their own body weight than a human. Picture eating 15 pounds of healthy foods per day and you might start to get those vitamin levels up there.

    Yes, but if you go on that logic, they're eating 10 times more of EVERYTHING--all vitamins, minerals, amino acids, fats (the idea that they consume their body weight a week is another question I want to research one day. I've read that it requires a pound of "mast" a week for them, but I haven't found evidence yet what percentage of that mast they actually eat). Obviously they are different than we are--their metabolisms and requirements. You could make that same argument for ANY nutritional element. The key word you used was "oversupplementation." I don't consider providing squirrels with a variety of veggies--some high in Vitamin A, some not--"supplementation." ADDING vitamins to a natural diet is supplementation--overdone or not.

    However, my main concern with frank vitamin A toxicosis is, of course, with fortified foods and vitamin supplements designed for birds since they contain large amounts of vitamin A, and it's almost never the nontoxic, natural form (beta-carotene), but rather the much more toxic (and cheaper) retinoids.

    I think any doctor or nutritionist would agree that the BEST way to get the necessary vitamins and minerals one needs is through natural foods. From what I've read, Vitamin A toxicosis has occurred primarily through gross oversupplementation. All blocks, including HHBs (and your blocks aren't the issue!), are supplemented with processed vitamins. Quite frankly, since so many foods have Vitamin A in them, and to use your argument, squirrels eat 10 times the food we do per body weight, I wonder why you supplement it (Vit A) at all if one feeds his or her squirrel a variety of vegetables (including the green, yellow, and orange) a week.

    Although HHBs are made with mostly beta-carotene, other rodent blocks contain retinoids--often at very high doses. So the idea behind limiting high vitamin A veggies is simply to keep all the nutrients in balance, understanding that different brands of rodent block may be fed. And in any case, we certainly don't want our squirrels turning orange!

    Ha! No orange squirrels for me! (But I do have three in my yard with orange tails--think there's a connection?). But again, the point was that they won't get Vitamin A toxicosis from the veggies. I'm sure you put the best quality/healthiest supplements in your HHBs, but again, why supplement something artificially that doesn't need supplementing if the squirrels can get it naturally?

    That being said, the Healthy Diet is super-conservative, admittedly. And I'm sure some of the "rules" there could be broken without harm.

    It's not the "rules" to be "broken" that's the issue, IMHO, but the possibility that the "rules" were made on the basis of inaccurate information"

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    Default Re: Spinach, Oxalates, Calcium, and Vitamin A toxicosis

    The Healthy Diet is always open to improvement. If you have changes to suggest, then by all means do so.
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    Default Re: Spinach, Oxalates, Calcium, and Vitamin A toxicosis

    My Jackie is very healthy and been on your squirrel diet since day 1. I know it could be changed but its not really broken, right.
    Almost everything in this post is misspelled

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  6. #6
    PBluejay2 Guest

    Default Re: Spinach, Oxalates, Calcium, and Vitamin A toxicosis

    Quote Originally Posted by crazysquirrels
    My Jackie is very healthy and been on your squirrel diet since day 1. I know it could be changed but its not really broken, right.
    I didn't post this information to change anything necessarily, or to suggest there's anything "unhealthy" about the "Healthy Diet," but I think we can relax a little bit about what veggies and how much we can feed them. There was a recent post about kale wherein the poster was encouraged to limit kale (high in calcium) because of Vitamin A. This initiated my inquiry since I give my squirrels both kale and collards every day (not that they eat them every day). Since my findings are that Vitamin A in vegetables cannot cause toxicosis (at worst orange skin) as was previously believed, and they won't OD on it, I feel better about the diet I offer. We might also want to rethink spinach, especially since from what I've read doctors and nutritionists believe that the other nutrients in it are of enough benefit that they outweigh the fact that there may not be much absorbable calcium in it and the oxalates in it do not block calcium contained in other foods. Face it, if we're warned against feeding too much yellow and orange and now dark green veggies (those highest in calcium), that really puts a limit on our choices. I'm all for feeding rodent blocks, and will most certainly continue to feed them myself, but in my view they are a vehicle for ensuring the squirrels get their vitamins and minerals (and, arguably, some protein). I believe there are other ways to ensure this, and until I see little bistros out in the wild that squirrels frequent to get blocks, I will continue to believe so. By and large, the cases of MBD and other nutritional problems we have seen have been cases where the owners had no clue about what to feed their pets and were feeding diets that were limited to either junk (crackers and Peanut M&Ms) and/or diets that were WAY unbalanced as far as calcium and phosphorus (corn, sunflower seeds, nuts).

    Once again, my intent was not to suggest that there is anything "wrong" with the "Healty Diet" as it exists. I fully understand that it's difficult for some to rethink the "givens" and venture outside of what they think is "the known," but I am of a mind that, even though something may "work" and not necessarily need "fixing," that doesn't mean it can't be improved or that it is beyond questioning. I have my own ideas about nutrition, some of which may not be what is currently commonly accepted, and will present them when I am ready, but until then I will share what I find concerning specific foods so that our squirrels might enjoy a more varied and natural diet.

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    Default Re: Spinach, Oxalates, Calcium, and Vitamin A toxicosis

    Again, if there are specific changes you'd like to see we can put them up for discussion.
    Last edited by Pam; 02-03-2010 at 06:48 PM.
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    Default Re: Spinach, Oxalates, Calcium, and Vitamin A toxicosis

    See this is exactly what I mean about healthy discussions. And what works for you may not be the best for me. I can dissect each persons theory and build mine to suit my or my babies specific needs. thank you for this information. Though I really can't digest all of it there are bits and pieces that I take from it.

    To all who have every loved a wild baby
    http://www.youtube.com/watch?v=5xpMl9AnaIg

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    Default Re: Spinach, Oxalates, Calcium, and Vitamin A toxicosis

    I stopped in, I read, I posted.
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    Handle every stressful situation like a dog. If you can't eat it or play with it, pee on it and walk away.

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    Default Re: Spinach, Oxalates, Calcium, and Vitamin A toxicosis

    I think the squirrel are alot like human. My grey is VERY PICKY. I do give her alot of good food. However she just refuses to eat it. She like spinish but only fresh. I only give it to he 1 week out of the month. She gets mushrooms everyday cause she loves them and needs them. I also give her mixed lettuses. I am not nutritionist but Jackie is very good about what she picks to eat. She refuses to eat fruits but that not bad since she really does not need the sugar. Now not all squirrels will be the same and I use the Healthy diet and a great foundation as what to feed her. I think the area people live in may be a factor in food as is the time of year when they are available. Clearly not every food is there on the list but its a great foundation to have and keep a pet healthy.
    Almost everything in this post is misspelled

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    Default Re: Spinach, Oxalates, Calcium, and Vitamin A toxicosis

    It makes me think of what has been found pertaining to human diets over the years. Everything in moderation (barring obviously toxic or harmful things).

  12. #12
    PBluejay2 Guest

    Default Re: Spinach, Oxalates, Calcium, and Vitamin A toxicosis

    Just wanted to copy here in case I need to find it later.


    As was discussed in another thread (see below), animals don't/can't get Vitamin A toxicity from vegetables, as we previously believed. At worst, their skin might take on an orangish hue. Vitamin A toxicity is associated with retinol, the form of vitamin A found in animal products, not naturally occurring beta carotine. Any problems associated with beta carotine seem to be the result of supplementation, especially with the synthetic forms of beta carotine manufactured for that purpose. Of course, none of us want our squirrels to turn orange, but I think we can offer our babies much more than the allotted tablespoon a month of yellow and orange vegetables suggested by the "Healthy Diet" and provide them with a much more varied and interesting and ultimately healthy diet. My own get some variety of squash (they love butternut) and sweet potato several times a week, kale and collards every day, along with a variety of other vegetables, and I have seen no adverse effects. Below is some info (my bold):

    "Most beta-carotene in supplements is synthetic, consisting of only one molecule called all trans beta-carotene. Natural beta-carotene, found in food, is made of two molecules - all trans beta-carotene and 9-cis beta-carotene. Beta-carotene is plentiful in vegetables and fruits, and is beneficial in this form. The 600 carotenoids are important for health and are found in yellow, red, and deep green vegetables and fruits. Carotenoids are polyisoprenoids which typically contain 40 carbon atoms and an extensive system of conjugated double bonds. They usually show internal symmetry and frequently contain one or two ring structures at the ends of their conjugated chains. Beta-carotene along with alpha-carotene, lycopene, lutein, zeaxanthin and beta-cryptoxanthin are the principal dietary carotenoids. Three of these carotenoids, alpha-carotene, beta-carotene and beta-cryptoxanthin, can serve as dietary precursors of retinol (all-trans retinol, vitamin A).

    Beta-carotene is the most potent precursor to vitamin A, but its conversion to vitamin A in the body is limited by a feedback system. Beta carotene has two roles in the body. It can be converted into vitamin A (retinol) if the body needs more vitamin A. If the body has enough vitamin A, instead of being converted, beta carotene acts as an antioxidant which protects cells from damage caused by harmful free radicals. The body converts beta-carotene into vitamin A, a nutrient first identified in the 1930s and now recognized as vital to the growth and development of the human body. It is an important antioxidant in its own right and one that can only build up to toxic levels in rare circumstances. Beta-carotene is considered a conditionally essential nutrient. Beta-carotene becomes an essential nutrient when the dietary intake of retinol (vitamin A) is inadequate.


    Beta-carotene (vitamin A) functions, uses, and health benefits

    --------------------------------------------------------------------------------

    The body turns it into vitamin A, and beta carotene is sometimes added to foods or vitamin supplements as a nutrient. The same long chains of conjugated double bonds (alternating single and double bonds) that give the carotenes their colors are also the
    reason they make good anti-oxidants. They can mop up oxygen free radicals and dissipate their energy. Vitamin A and its analogs have shown the ability to help inhibit cancer cell proliferation and help in returning to normal growth patterns. Individuals with highest levels of beta-carotene intake have lower risks of lung cancer, coronary artery heart disease, stroke and age-related eye disease than individuals with lowest lvels of beta-carotene intake. Its inhibitory effects are especially potent against leukemia and certain head and neck cancers. Beta-carotene may have a role to play in staving off heart disease, apparently a function of its ability to keep harmful LDL cholesterol from damaging the heart and coronary arteries. Beta-carotene has been shown to have benefits to the immune system.
    Like all other carotenoids, beta-carotene is an antioxidant. Antioxidants are substances that help prevent or reduce the formation of damaging chemicals in the body called free radicals. Consuming foods rich in beta-carotene appears to protect the body from damaging molecules called free radicals. Free radicals cause damage to cells through a process known as oxidation, and over time, such damage can lead to a variety of chronic illnesses. Beta-carotene's antioxidant actions make it valuable in protecting against, and in some cases even reversing, precancerous conditions affecting the breast, mucous membranes, throat, mouth, stomach, prostate, colon, cervix, and bladder. Beta carotene is sometimes added to products for its anti-oxidant effects, to keep fats from going rancid


    Beta-carotene (vitamin A) dosage, intake, recommended daily allowance (RDA)

    --------------------------------------------------------------------------------

    No RDA has yet been established for beta-carotene, but vitamin A is essential for health, and beta-carotene is converted into vitamin A in the body. The exact conversion factor varies with the circumstances; in general, 2 mcg of beta-carotene in supplement form is thought to be equivalent to 1 mcg of vitamin A. Adults and teenagers need 6 to 15 milligrams (mg) of beta-carotene (the equivalent of 10,000 to 25,000 Units of vitamin A activity) per day. Children need 3 to 6 mg of beta-carotene (the equivalent of 5,000 to 10,000 Units of vitamin A activity) per day. For general health, 15 to 50 mg (25,000 to 83,000 IU) per day is recommended. For adults with erythropoietic protoporphyria, 30 to 300 mg (50,000 to 500,000 IU) per day for 2 to 6 weeks is recommended. The RDA for vitamin A for women who are breast-feeding increases from 800 mcg RE to 1300 mcg RE. This can be met by increasing the intake of beta carotene rich foods. Smokers should be made aware that supplemental intake of beta-carotene of 20 milligrams daily or greater were associated with a higher incidence of lung cancer in smokers.


    Sources of beta-carotene

    --------------------------------------------------------------------------------

    The richest sources of beta-carotene are yellow, orange, and green leafy fruits and vegetables (such as carrots, spinach, lettuce, tomatoes, sweet potatoes, broccoli, cantaloupe, and winter squash). The more intense the green, yellow or orange color the more beta carotene the vegetable or fruit contains. Beta carotene is not destroyed by cooking which, in fact, may make it easier to absorb. In dietary supplements, beta-carotene is available as synthetic all-trans beta-carotene, beta- and alpha-carotene from the algae Dunaliella, and mixed carotenes from palm oil.

    Beta-carotene (vitamin A) deficiency

    --------------------------------------------------------------------------------

    A low dietary intake of carotenoids such as beta-carotene is not known to directly cause any diseases or health conditions, at least in the short term. However, long-term inadequate intake of carotenoids is associated with chronic disease, including heart disease and various cancers. One important mechanism for this carotenoid-disease relationship appears to be free radicals. Research indicates that diets low in beta-carotene and carotenoids can increase the body’s susceptibility to damage from free radicals. As a result, over the long term, beta-carotene deficient diets may increase tissue damage from free radical activity, and increase risk of chronic diseases like heart disease and cancers. Diets low in beta carotene may reduce the effectiveness of the immune system and lead to an increased risk of cancer and heart disease. Old persons with type 2 diabetes have shown a significant age-related decline in blood levels of carotenoids, irrespective of their dietary intake. Symptoms of a beta-carotene deficiency mimic those of a vitamin A deficiency: dry skin, night blindness, susceptibility to infection. Such deficiencies are seldom seen, however, even in people who don't eat fruits or vegetables or take supplements, because so many other foods supply the nutrient.


    Beta-carotene overdose and toxicity

    --------------------------------------------------------------------------------

    Supplementing the diet with beta-carotene does not produce any significant toxicity despite its use in very high doses in the treatment of numerous photosensitive disorders. At recommended dosages, beta-carotene is believed to be very safe. High intake of carotenoid-containing foods or supplements is not associated with any toxic side effects. But the skin may turn slightly yellow-orange in color when extra large amounts are taken. But will return to normal with decreased dosage. However, long-term use of beta-carotene supplements, especially at doses considerably above the amount necessary to supply adequate vitamin A, might slightly increase the risk of heart disease and certain forms of cancer. Beta-carotene supplementation may also decrease blood levels of lutein, another carotenoid.


    http://www.vitamins-supplements.org/beta-carotene.php


    http://thesquirrelboard.com/forums/s...ad.php?t=21270
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    Default Re: Spinach, Oxalates, Calcium, and Vitamin A toxicosis

    No one is disputing the health benefits of vitamin A and beta-carotene. In fact, I wrote a research paper about it 30 years ago, when the idea that certain foods might contain compounds with anti-cancer properties was still fairly radical.

    The concern about vitamin A arose initially because of a rash of sudden deaths in otherwise healthy flying squirrels. After studying the necropsy results and comparing those findings with studies on vitamin/mineral toxicities in rodents, one possible culprit emerged: Vitamin A. I'm pretty sure that this would have been caused by a fortified bird food that was being fed, or some other supplement; not from eating pumpkin. When I consulted Dr. Calvert, he felt that too much vitamin A, in conjunction with a couple of other factors in the stated diet history of the dead flyers, would have created a serious imbalance in the diet. Furthermore, he stated that, in his opinion, "nutrient-dense, energy-dense" foods such as sweet potato, squash, pumpkin, corn, etc. should NEVER be fed to captive squirrels, especially tiny flyers.

    So, perhaps out of an abundance of caution, I decided to add the asterisk to those foods in the Healthy Diet, advising that they be limited.

    If you feel the limits should be raised, we can certainly discuss that. But someone needs to crunch the numbers again, and we need to discuss with the community whether they're comfortable with their squirrels taking in 10 to 20 times the recommended amount of any nutrient.
    Last edited by 4skwerlz; 02-05-2010 at 09:16 AM.
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  14. #14
    PBluejay2 Guest

    Default Re: Spinach, Oxalates, Calcium, and Vitamin A toxicosis

    Quote Originally Posted by 4skwerlz
    The concern about vitamin A arose initially because of a rash of sudden deaths in otherwise healthy flying squirrels. After studying the necropsy results and comparing those findings with studies on vitamin/mineral toxicities in rodents, one possible culprit emerged: Vitamin A. I'm pretty sure that this would have been caused by a fortified bird food that was being fed, or some other supplement; not from eating pumpkin. When I consulted Dr. Calvert, he felt that too much vitamin A, in conjunction with a couple of other factors in the stated diet history of the dead flyers, would have created a serious imbalance in the diet. Furthermore, he stated that, in his opinion, "nutrient-dense, energy-dense" foods such as sweet potato, squash, pumpkin, corn, etc. should NEVER be fed to captive squirrels, especially tiny flyers.

    Did he do an actual study on this, something we might get our hands on? And was there any conclusive evidence/proof that the flyers died of Vitamin A toxicosis? Also, I assume this wasn't any actual experiment, so not knowing the kind of bird seed, what the vitamin A source was in it, plus the amounts they received from both the seed and any vegetables leaves me with nothing but questions. Finally, where did this "rash of sudden deaths" occur? Were all these squirrels in possession of one owner (If so, it seems like there could be numerous causes of their deaths), or did there just happen to be a "rash" of separate owners who fed a particular kind of bird seed along with a diet high in vitamin A? I respect his opinion, but "nutrient dense, energy dense" is a bit of a vague term that could be applied to about any kind of rodent block. Also, in NRLA, it states plainly that vitamin A toxicosis can occur if rats are fed 180 micromols/kg BW/day of diet if the source is retinol, but Beta carotine was not toxic at doses up to 1,800 micromols/kg BW/day," and I'm sure the scientists pumped the rats just as full as they could in an attempt to find a toxic level.



    If you feel the limits should be raised, we can certainly discuss that. But someone needs to crunch the numbers again, and we need to discuss with the community whether they're comfortable with their squirrels taking in 10 to 20 times the recommended amount of any nutrient.
    I think "in moderation" would be sufficient as far as what to put in the healthy diet, but I don't know where you get the numbers 10 and 20.

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    Default Re: Spinach, Oxalates, Calcium, and Vitamin A toxicosis

    Quote Originally Posted by PBluejay2
    Did he do an actual study on this, something we might get our hands on?
    Did who do a study on what?
    Quote Originally Posted by PBluejay2
    And was there any conclusive evidence/proof that the flyers died of Vitamin A toxicosis? Also, I assume this wasn't any actual experiment, so not knowing the kind of bird seed, what the vitamin A source was in it, plus the amounts they received from both the seed and any vegetables leaves me with nothing but questions.
    Yup. More questions than answers for sure. There's a whole 'nother thread somewhere about my attempts to find out from the manufacturer the actual vitamin/mineral content of the bird food in question.
    Quote Originally Posted by PBluejay2
    Finally, where did this "rash of sudden deaths" occur? Were all these squirrels in possession of one owner (If so, it seems like there could be numerous causes of their deaths), or did there just happen to be a "rash" of separate owners who fed a particular kind of bird seed along with a diet high in vitamin A?
    Different owners.
    Quote Originally Posted by PBluejay2
    I respect his opinion, but "nutrient dense, energy dense" is a bit of a vague term that could be applied to about any kind of rodent block.
    Welp, there's more vitamin A in 3 tablespoons of sweet potato than in 2 pounds of HHB's, 9 times the glycemic load, 12 times as much sugars...I could go on. Three tbsp sweet potato has 400% of the HUMAN requirement of vitamin A.
    Quote Originally Posted by PBluejay2
    Also, in NRLA, it states plainly that vitamin A toxicosis can occur if rats are fed 180 micromols/kg BW/day of diet if the source is retinol, but Beta carotine was not toxic at doses up to 1,800 micromols/kg BW/day," and I'm sure the scientists pumped the rats just as full as they could in an attempt to find a toxic level.
    One more time: frank vitamin A toxicosis is a concern with RETINOIDS not beta-carotene. Still, IMO large overdoses of ANY nutrient are a bit of a concern when trying to create a balanced diet.

    Still not sure what your point is....
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  16. #16
    PBluejay2 Guest

    Default Re: Spinach, Oxalates, Calcium, and Vitamin A toxicosis

    Quote Originally Posted by 4skwerlz
    Did who do a study on what?

    I thought you said Calvert examined the necropsy reports of these squirrels. Did he do any kind of report on his study of them, and is that available? I assume each and every one of these necropsies included blood work, tissue histopaths, and so forth to rule out any other cause? No offense to Dr. Calvert, but a nutritionist is naturally inclined to look for a nutritional cause.

    Yup. More questions than answers for sure. There's a whole 'nother thread somewhere about my attempts to find out from the manufacturer the actual vitamin/mineral content of the bird food in question.

    Point me there?

    Different owners.

    How did these squirrels with different owners happen to be collected? Did these different owners take their squirrels to the same place for necropsy? Or did Calvert somehow collect the necropsy results from different places and began to look for commonalities. Was he able to determine that each of these squirrels (how many were there, by the way) were fed a similar diet high in vitamin A or simply they were all fed the birdseed or neither or both?

    Welp, there's more vitamin A in 3 tablespoons of sweet potato than in 2 pounds of HHB's, 9 times the glycemic load, 12 times as much sugars...I could go on. Three tbsp sweet potato has 400% of the HUMAN requirement of vitamin A.

    But if it's Beta carotine, it doesn't matter. By the way, how much does a "batch" (one month's supply) of HHBs weigh? I seem to remember 12 oz., but I may be wrong. Also, if squirrels eat their body weight a week (as is suggested), they are more than likely going to get several times as much of many nutrients in relation to body weight as humans do.

    One more time: frank vitamin A toxicosis is a concern with RETINOIDS not beta-carotene. Still, IMO large overdoses of ANY nutrient are a bit of a concern when trying to create a balanced diet.

    One more time, then since vegetables don't contain retinoids but Beta-carotine, we should stop scaring people away from them by claiming in the "Healthy Diet" that they may cause vitamin A toxicosis.

    Still not sure what your point is....

    I'll try to spell it out: Again, the Beta carotine in vegetables does not cause Vitamin A toxicosis, as is suggested in the "Healthy Diet" and as many have been led to believe. People should feel free to feed those yellow, orange, and dark green vegetables in moderation (as anything should be fed in moderation, including blocks), particularly because those same vegetables contain many other important nutrients but also because feeding them to squirrels will provide those squirrels with a more varied, interesting, and enjoyable diet and will enable owners not to feel so stifled in their selections when they push their carts up and down the produce aisles.
    PBJ

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    Default Re: Spinach, Oxalates, Calcium, and Vitamin A toxicosis

    Dr. Calvert didn't do the necropsies. The veterinarian that did concluded that oversupplementation was a possible cause of death as he found no evidence of disease and did find abnormal levels of some nutrients in the tissues. I consulted Dr. Calvert later regarding feeding certain foods high in vitamin A.

    I really don't have time to go over the whole history here. If you're interested in pursuing the flyer deaths further, PM me and I'll ask my contact if she's willing to be contacted by you.

    If you want to change the recommendation on certain veggies, just start a thread and everyone can discuss it. That's how we do these things. By consensus. I'm not "the decider."

    Whole thing seems like a tempest in a teapot to me. Sheesh.
    Last edited by 4skwerlz; 02-05-2010 at 01:42 PM.
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  18. #18
    PBluejay2 Guest

    Default Re: Spinach, Oxalates, Calcium, and Vitamin A toxicosis

    Quote Originally Posted by 4skwerlz
    Dr. Calvert didn't do the necropsies. The veterinarian that did concluded that oversupplementation was a possible cause of death as he found no evidence of disease and did find abnormal levels of some nutrients in the tissues. I consulted Dr. Calvert later regarding feeding certain foods high in vitamin A.

    "Over supplementation" seems to be the key phrase to me. Again, I don't regard getting nutrients from foods as "supplementation." When vitamins and minerals are ADDED to foods, that's supplementation. Since, I assume, all these flyers were given the same bird seed, and they had different owners who no doubt had their own preferences/differences in the natural foods offered, I would think the seed would be the culprit as it is/was the only common factor (unless there are unknown others such as the squirrels all coming from the same breeder or such). I wonder if a full toxicology screen was done. Some poisons are hard to detect. You said "some nutrients" were found at abnormal levels. Do you know what others? Since Beta Carotine does not cause vitamin A toxicosis, any foods high in Beta Carotine were not the cause. The symptoms of vitamin A toxicosis are progressive and don't include "sudden death" from what I can find.

    I really don't have time to go over the whole history here. If you're interested in pursuing the flyer deaths further, PM me and I'll ask my contact if she's willing to be contacted by you.

    If there is no conclusive evidence as to what killed them, I suppose conjecture is the best anyone could do.

    If you want to change the recommendation on certain veggies, just start a thread and everyone can discuss it. That's how we do these things. By consensus. I'm not "the decider."

    Thank you for letting me know "how we do things." I did start a thread--THIS one. As far as I'm concerned, anyone is welcomed to weigh in.


    Whole thing seems like a tempest in a teapot to me. Sheesh.

    I don't see it that way. I think accurate information regarding any and all foods and their risks and benefits of great importance. It is to me, anyway. I would imagine that many have been avoiding certain foods (yellow, orange, dark green) because of inaccurate information when those foods may be good sources of important nutrients (eg Kale and calcium). Who knows? One day we might discover that certain foods we all think are wonderful are really not so wonderful afterall.
    PBJ

  19. #19
    PBluejay2 Guest

    Default Re: Spinach, Oxalates, Calcium, and Vitamin A toxicosis

    Okay, people, time to put down the popcorn and weigh in on this.

    BTW, 4s, since you've put a copyright notice on the healthy diet chart, I think we should have a healthy diet sticky that belongs to the board and is considered in the public domain.

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    Default Re: Spinach, Oxalates, Calcium, and Vitamin A toxicosis

    Popcorn down and heads for the scale.135... ohhh hey that's down a few more!

    I'd weigh in but I have no credentials here so I feel unqualified.

    Here's all I've learned from the horses. Unless your forage is very deficient for some reason, most of the time the animal will get what it needs and not more than it needs from what it naturally eats. We tend to get into trouble with concentrated foods (pellets, supplements etc).

    The difference with domestic horses as compared to squirrels is the horses are fenced in and if their forage (which tends to be all the same in a pasture for the most part) is over abundant on one nutrient and lacking in another we have issues. With your indoor squirrel you are offering many choices so they aren't forced to eat ONE thing all the time.

    Ideally we would test all our hay to find out the % of sugar, protein, calcium, phosphorous and so forth but that's not overly practical day to day.

    I would think,this is just my thought on the matter and by no means backed by any kind of study, that if you are offering a good balance of "forage" you would be hard pressed to overdo any one nutrient to the point of toxicity.

    The only thing I could see being an issue is if you had an extremely fussy eater who was preferring one food over another to the point of excluding all others.

    Scooby eats EVERY morsel of everything I put on her plate. It's literally empty by the time I feed her again. As long as I vary the produce and provide her some sort of pellet (in moderation I don't want her overdoing those either) I feel like I'm providing her a balance. I honestly don't think a little spinach on her plate daily is going to tip her into some sort of negative balance.

    I'm going back to all things in moderation. I've been feeding every color in the rainbow to Scooby including spinach and kale for the last two years. So far so good. I don't feed any one thing in huge quantity and she is a super eater.

    We have to keep in mind these guys are pretty hardy. Even living outside their diets become unbalanced due to availability of food sources. Sometimes they are eating mostly one single thing because of environmental factors. They are also resourceful and eat things from our homes and feed rooms they probably shouldn't. Still and all they seem to thrive.

    That's my fairly worthless opinion on the topic. Can anyone tell I'm avoiding morning chores?

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