In a large bowl or plastic bag, combine sorghum flour, amaranth flour, flax flour, potato starch, cornstarch, sugar, xanthan gum, yeast, salt, flaxseed and sunflower seeds; mix well and set aside.
Pour water, oil and vinegar into the bread machine baking pan. Add eggs and egg whites.
Select the Dough Cycle. As the bread machine is mixing, gradually add the dry ingredients, scraping bottom and sides of pan with a rubber spatula. Try to incorporate all the dry ingredients within 1 to 2 minutes. When the mixing and kneading are complete, remove the kneading blade, leaving the bread pan in the bread machine. Quickly smooth the top of the loaf. Allow the cycle to finish. Turn off the bread machine.
Select the Bake Cycle. Set time to 60 minutes and temperature to 350°F (180°C). Allow the cycle to finish. Do not turn machine off before taking the internal temperature of the loaf with an instant-read thermometer.
It should be 200°F (100°C). If it’s between 180°F (85°C) and 200°F (100°C), leave machine on the Keep Warm Cycle until baked. If it’s below 180°F (85°C), turn on the Bake Cycle and check the internal temperature every 10 minutes. (Some bread machines are automatically set for 60 minutes; others need to be set by 10-minute intervals.)
Once the loaf has reached 200°F (100°C), remove it from the pan immediately and let cool completely on a rack.