The thread you found is very, very old. You can post your own and probably get more answers. Just hit "post new topic."
As was said there aren't really any natural remedies that will cure GERD. However, you may be able to reduce your symptoms if you find you have specific food triggers. You are right in suspecting additives, not that they necessarily are your problem.
I was able to get rid of most of my reflux by keeping a food journal - natural and free. My allergist got me doing this and later doing some food challenges. I still had a bad lower esophageal sphincter and needed acid reducers to keep the fluid that flowed into my throat at night. I also got rid of my heart arrhythmias that were triggered by my esophagus and stomach not tolerating specific foods. My problem turned out to be sulfites - a common additive but also natural in a few foods like wine and beer. You may not have a similar problem, but it's worthwhile to spend a couple of months writing down everything you ingest to see if it helps. The commonly cited "GERD Diet" didn't do anything for me. I tolerate many foods in it and cannot eat other foods.
Do you have any reflux when you go to bed after eating? The would be an indication of a possible lower esophageal valve not working properly.
In any case, seeing a gastroenterologist is my best advice. We're not doctors here on the forum. We can only tell our own experiences.
Nissen 6/06 and 5/09
#3 on 8/24/11