Wednesday, October 27, 2010

Is Butter High in AGEs?

20 comments:

  1. So maybe some of the more AGE-resistant foods (like butter) resulted in less complex structures, better targets for the antibodies?

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  2. Chris, did you see that the butter used in the Mount Sinai study was whipped? My concern is that the whipping process might distort the results.

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  3. With dietary AGEs being present in virtually all cooked food to some degree, should we even care? I have to think that we're equipped to deal with such things.

    It is endogenously-produced AGEs that I worry about.

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  4. Donny and Stephen,

    Yes, I saw that it was whipped. I find it much more likely that, as Donny suggested, the whipping distorted the stucture, perhaps shredding it apart, to make the existing CML better targets for the antibodies, than that whipping butter is 500 times more effective at producing CML than evaporating milk.

    That said, this doesn't explain why, on the whole, all their fats and oils were very high. So, I think part of the issue is that these antibodies just aren't accurate. In fact I have more certain reasons to believe that AGE antibodies have abysmal specificity and I'll write about those reasons in the future. Suffice it to say for now, I take anything on AGEs that uses immunoassay quantification with a grain of salt and if I am forced to use these antibodies for my dissertation work (which, thankfully, it appears I will not be), I would be embarassed to publish it.

    Nathaniel, AGEs are present even in raw foods. Yes, most of us are equipped to deal with them. Whether we deal with them perfectly is an issue worth discussing. In any case, that's another matter for a future post.

    Yes, endogenous AGEs are of much greater concern. More posts on that coming in the next few months too.

    Chris

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  5. Dr Davis has been hating on butter for a while. Someone made a comment on his blog along the lines of whether exogenous AGE's even enter the blood stream after digestion. Does a high consumption of exogenous AGE's promote higher levels of endogenous AGE's?

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  6. James,

    There is some evidence that about 10% of AGEs enter the bloodstream in both humans and rats. The rat evidence is of good quality whereas the human evidence is a much more poorly designed experiment by the same group. In humans without kidney disease, these AGEs are rapidly excreted.

    There is pretty good evidence that high-heat cooking has a variety of negative effects on clinical parameters in people who are not in the best of health, but very little indication it is due specifically to the exogenous AGE content of those foods.

    So, there are two reasons why it is ridiculous to make dietary conclusions from an AGE database: first, the evidence is incomplete to say the least that dietary AGEs are a problem; second, AGE databases with immunoassays should be more or less ignored until the immunoassay is validated with mass spectrometry for use across a broad spectrum of food groups and processing types, which is not the case currently.

    Chris

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  7. Wow, this is such a relief! Not that I would have given up my pasture butter anyway!

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  8. Chris,
    Thanks for the post! Do you know if the milk in these trials was raw or pasteurized? It seems that would make a big difference in the quantity of AGEs in the whole milk.

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  9. Austin,

    The mass spectrometry study looked at raw and pasteurized whole milk and found about 70% higher CML in the pasteurized milk. The comparison I made between butter and whole milk was based on the pasteurized milk. In the antiobody study, the only milk they looked at was commercial whole milk.

    Chris

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  10. I was rather devastated after Dr. Davis' article. I am excited to see new info. Thanks for posting Chris.

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  11. Hi Chris,

    Excellent work. I was not devastated by Dr. Davis' article. I knew someone would put the smack down on this. Your points make great sense. Anyways, if butter really did have 5000 times the AGEs of whole milk, we would be seeing many of the well known whole health gurus who eat butter as a staple develop significant health issues after years and years of consumption. But, alas, that is not the case. Sometimes, common sense can lead the way. Here, you have bridged common sense with a detailed explanation. Well played.

    Jack Kronk

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  12. Hi Chris,

    Awesome. I was puzzled by the butter result too. Why would butter contain way more CML than you'd expect from taking the fatty fraction of whole pasteurized milk? Butter isn't heated after extraction, so it makes no sense. Also, according to their data, extra virgin olive oil has nearly as much CML as butter if I recall correctly. Now that makes no sense whatsoever. Dr. Davis neglected to mention that in his post.

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  13. I've read the paper that lists butter as a high-AGE food: "Advanced Glycoxidation End Products in Commonly Consumed Foods" (2004, Journal of the American Dietetic Association, via Google Scholar cache).

    Here are some numbers from Table 1:

    Milk, cow, whole .... 0.05 kU/mL
    Butter .............. 265 kU/g

    The table caption refers to "foods prepared by standard cooking methods" (these include frying). The table doesn't say that the butter was used in cooking, but I'd be willing to bet that it wasn't raw!

    Expecting high AGEs in uncooked butter -- over 5000 times the level in milk! -- would make little sense. There's every reason to think that this butter had been exposed to high temperatures.

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  14. Ed, certainly the butter and milk were both pasteurized. There is a much newer paper I cited by the same authors that has similar data but many more foods. I do not think they fried the butter. That would be extremely disingenuous, and I think they make it clear that they fried the thigns that are commonly consumed fried. No one repeatedly fries things in butter and then consumes the butter.

    I think it is very much missing the point to believe that the result is an effect of temperature. The result is most likely an effect of the assay having no specificity for CML.

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  15. Nice post. What's your opinion on butter vs ghee on a health point of view?

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  16. Hi Chris,
    I had to check out your blog after your excellent talk on Saturated fats and PUFAs on the cruise. Great technical analysis on what I hope can be refiled as a non issue for butter lovers. It's good to know your informative blog is available for us microbiologists who know just enough analytical chemistry to be dangerous.

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  17. I eat all animal products raw and only cook vegetables/starches(and perhaps bones). Boiling and steaming are the only cooking methods I use.

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  18. I know that this is an old post, but like Florent I'm really curious about ghee as well. I would really appreciate your weighing in on it!

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    Replies
    1. I think ghee is better for cooking and butter is better for spreading or melting on top of hot things.

      Chris

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  19. It made no sense that butter would be high in AGE's.Thank you for setting things straight.

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