You really do need them to add that salty / umami flavor however, if you can find them locally and you tolerate soy, then you could replace them with gluten - free tamari sauce (using about 1/2 of the amount called for in the recipe + a few extra tablespoons of juice from the canned pineapple to get that salty / umami taste). (therealfoodrds.com)
Seems like maybe a few extra tablespoons sorghum + a couple of teaspoons flaxseed meal + maybe an extra tablespoon of potato starch may do the trick. (allysonkramer.com)
Thin with a few extra tablespoons of water if needed, but try to keep it to a minimum. (connoisseurusveg.com)