There are lots of different minerals and other nutrients in bone. Bone is also a multilayered part of any vertebrate's body.
Layer by layer, here is what is in bone:
Mostly protein and phospholipids. Not much else. This is the membrane surrounding the bone.
This would be the toughest part to digest because of hydroxyapatite. High calcium and phosphorus in this layer as well as some protein.
This would still be hard to digest but not as hard. There is hydroxyapatite here too but not as much and there is more fat. In the spaces within the spongy bone is bone marrow. This bone marrow is by far the most nutritious part of the bone. High iron, fat, protein etc.
In fact per 100 grams of bone marrow, there is 25% of the iron your body needs. This may sound small since we only need single digit milligrams of iron a day but this is actually very significant since most foods have 2% of required iron or lower.
Organ meats are the only animal products with higher iron than bone marrow.
In both of these, Iron is predominantly in the form of Heme which is easily absorbed.
So anyway I was thinking for the pregnant women when I thought that my people should eat bone. More iron is needed so unless you either:
1) Eat a lot of plants frequently(like every 1-2 hours)
2) Eat meat exclusively, less often(this risks heart disease though
3) Eat a mixed diet making sure to include bone marrow and/or organ meats often.
you are going to end up with Iron Deficiency Anemia while pregnant.
Worse still meat and high amounts of food increases nausea while pregnant.
So this leaves 1 option for high iron food that doesn't risk worsened nausea as much, bone marrow.
Extra calcium and phosphorus is needed to prevent osteoporosis in pregnancy.
And of course carbs, fat, and protein are in higher demand, especially protein and carbs.
Bone fits all except higher carbs but that demand can easily be resolved with fruit.
So I was thinking that since pregnant women would benefit from eating bone, anybody except for infants and toddlers should have bone as part of their diet. The reason why toddlers shouldn't eat bone? Delicate digestive system.
And of course with infants, eating bone not only risks getting a GI bleed but is also too hard to be digested by infants.
So should my people eat bone given all these benefits, especially for pregnant women?