Health food stores have stocked that for years, sometimes for various claimed health benefits. Amaranth is easy to grow, and like another American weed, Quinoa, will produce at high altitude.
Amaranth AKA “pigweed”. Leaves are supposed to be a good spinach substitute or pot herb, too.
Huge family, and some surprises as to family/subfamily member generas, one of which is beta (beets)...that takes us to Swis chard, and many other common (and some not so common) garden veggies.