I don't profess to be a botany expert. I know a fair amount about edible plants, plants I have grown and would like to grow and some about the native plants here...not nearly enough about any of these. So without meaning to sound like a snob...several people I have met who are either into this sort of thing or are uber-health foody (which is to say, even more extreme than I am, which is saying something), don't seem to know beans about botany and basic plant family trees. This would be OK if they weren't striking a lot of foods off their lists of acceptable items based on mistaken relation status. For example, despite the names, coffee beans and cocoa beans are in no way legumes, despite being called beans. Buckwheat is a dicot, while wheat and all true grains are monocots. So yes, buckwheat is gluten free and not a grain, neither are amaranth or quinoa. Not sure about teff- I'll have to find out. These are all seeds which are used as grains. To explain further, all plants which grow from seeds (i.e. not ferns, mosses, liverworts, etc) can be classified as either monocot or dicot. Monocots have one seed leaf, dicots have two. This is the most basic differentiation before you proceed any farther on keying a plant out. Monocots and dicots have a lot of differences, but basically, all grains are monocots, as are all plants of the lily family, Liliaceae, including for example onions and garlic and daffodils. Pine trees are monocots as well. When in doubt, look at the leaves: monocots always have parallel leaf veins (example, tulips) whereas dicots have more of a webbed or branching pattern on the leaves, (maple leaves). Buckwheat is from the family Polygonaceae and is closely related to sorrel and rhubarb- all dicots. So when people say that buckwheat has gluten because it's related to wheat....well, it just makes my brain want to cry.
That rant aside (sorry!)....not very long ago, many of the same plants we eat hadn't been bred for the kind of size that we are accustomed to today. Fruits in particular were smaller, probably many of the root crops were as well. What this means is that if one were to eat a pound of apple today and a pound of apple 400 years ago, the pound of apple in the past would have quite a lot more skin and fiber in proportion to pulp. The same is likely true of anything else we would eat the peels or fiber of. When you must eat 5 apples to equal one the size found in stores today, there is going to be a lot more peel but also far more of whatever nutrients are in or just under the peel. By breeding for maximum size in vegetables, we've been depriving ourselves of both fiber and vitamins and god only knows what else. We could eat exactly the same amounts of roughly the same food as someone ate a thousand years ago and we are not going to be getting the same things from it, even if it's been grown very conscientiously. Our plant foods have changed dramatically in the last 200 years alone. I don't know that it's possible to replicate what was eaten a very, very long time ago. The plants are simply not the same unless we go back to the ancient, primitive forms. This concerns me. By overbreeding our food so that it can be high graded, are we making colon cancer (and god knows what else) more likely? Is there any practical way to determine what was actually eaten in ancient times and whether our modern equivalent is at all comparable to it?