Part of the problem with foods made from plants (particularly grains) is that you need to eat soooo much more of them to absorb the same amount of protein and micro-nutrients you'd get from almost any kind of animal food - and that's just the nutrients that happen to be available from plant foods.

Back when I was subsisting on huge quantities of junk (even if most of it was homemade junk), I often had cravings for certain foods. One of the weirdest cravings was black olives, and it took me a while to figure out why I was craving black olives: turned out that it was the ferrous gluconate added to the liquid in the canned olives to help maintain the dark color of the olives. Ferrous gluconate is a form of iron. Was there a significant amount of iron in those black olives? Absolutely not - the brand I was buying specifically said that they were not a significant source of iron. (This was before nutrition labels had to provide percentages of iron - nevertheless, if they'd had even 5% RDA, I feel certain the label would have mentioned even that tiny amount) But even being such an insignificant amount that the olives I was buying didn't feel it was worth even mentioning, apparently my brain/body knew it was getting at least a little bit of iron from them, because I craved them.

And yet... that junk that I was making at home? There was a lot of bread and soft pretzels. In other words, lots of flour. One of the nutrients that is added to flour is... you guessed it: Iron. For most flour, they add enough iron that a 1/4 cup serving is supposed to have approximately 10% of your RDA. (I assure you I was eating at least 12 servings worth of flour daily, because not only were the wheat products quite addictive, I was always ravenous)

And yet with all my flour consumption, I still needed iron. I needed iron so desperately that my body was trying to get it from black olives that had so little iron that it was declared on the label to be insignificant.



So I don't doubt one bit that wheat is doing something to block the absorption of iron (and quite likely other nutrients as well), something that the canned black olives was not doing - that the canned black olives somehow helped me absorb the insignificant amount of iron in the olives so much better.