Phytic Acid Steals Minerals but Does Some Nice Stuff Too
Phytic acid isn’t well understood (at least, its impact on human health isn’t), but it’s definitely found in many nuts and grains (white flour and rice have far less of it; it’s mostly in the hulls/bran), and is good at removing minerals (by chelation) from the human body, e.g. zinc and iron, which is generally bad. On the other hand, it’s nice for removing uranium from the body. It also reduces colon cancer. It penetrates the brain and can protect neurons there by chelating iron (which I guess you don’t want in the brain - iron does get in there somehow and exacerbates many brain diseases).
Grain consumption has long been known to damage vitamin D status and bone health. Indeed, it is difficult to induce bone frailty in laboratory animals without feeding them grain. In Edward Mellanby’s original experiments leading to the discovery of vitamin D, he induced rickets by feeding dogs a diet of oats or wheat bread.  In human infants, wheat bran induces rickets.  In addition to interfering with vitamin D, grains also contain high levels of phytic acid, which interferes with bone mineralization by blocking absorption of calcium and magnesium.source (while making fun of Gwyneth Paltrow’s ridiculous macrobiotic diet)
Another crucial factor in bone health is vitamin K2. Since dairy fats are the leading source of vitamin K2, it’s likely Ms. Paltrow was deficient in this crucial vitamin. Most people are deficient in vitamin K2 – let alone those who avoid meats and dairy. In clinical trials, vitamin K2 supplementation reduced non-vertebral fractures by a remarkable 81%. reduced by 81% = 1/5 the odds. I like milk. Funny that they thought it was calcium (with supplemented D to aid absorption) that made milk bone-friendly, since it’s pretty easy to get enough calcium in general.
a high omega-6 to omega-3 ratio reduces bone density.omega-6 = vegetable oil (roughly - saturated vegetable oils obviously aren’t), omega-3 = fatty cold water fish The fact that paleo people get excited about phytic acid shows that they’re looking for confirmation of their already-held beliefs (grain is bad! etc.) Fermentation, cooking, and sprouting whole grains, significantly reduce phytic acid content. Almonds and sesame seeds are very high in it; toasting them might help. It seems like you can benefit from moderate phytic acid (nullifying iron in your brain sounds good), by simply ensuring you have excess of the minerals it chelates and steals from you.