Generally speaking, I do not eat much wheat or bread anymore. Occasionally, I may eat some pasta, pita or naan breads, but I do not eat sandwiches regularly.
The only breads I liked are pita bread and naan bread. A few years ago I used to get home baked, whole wheat pita bread from a nearby Greek store. It contains simple ingredients such as whole wheat, salt and water. (By the way, baked foods contain a lot of salt, so watch out!) One day the pita bread caused me stomach pain right after I ate it. I thought it was strange as it never caused me a problem before. Later on, I tried again, then I got stomach pain again. Immediately I suspected that the bread maker must have changed the flour, so I stopped eating the pita bread completely.
The only local breads I can eat without stomach pain is the naan bread from local Indian and Pakistani homemade restaurants. I like Indian foods. By then, I figured out that they may be using the flour from a different source. Yesterday, I had courage to ask the restaurant manager about the origin of the flour that they use to make the naan bread. He told me that they used whole wheat flour imported from their country. My guess was right.
I occasionally make pasta, but when I buy it, I only choose pastas that have been imported from Italy. They do not give me a stomach ache.
It is already known that wheat flour that is produced in the U.S. can cause lots of problems in the digestive tract. Wheat grown in the U.S. may contain GMOs (genetically modified organisms,) or it may be contaminated with GMOs, in order to resist the use of Roundup or any other agricultural herbicides and pesticides. A recent study shows that those GMO foods and the use of the agricultural herbicides containing “glyphosate” can destroy beneficial gut bacteria, thereby promoting food allergies. A researcher claims that antibiotics used for agriculture cause allergic reactions as well as antibiotic resistance.
I suggest that my patients cutout flour/gluten products, especially those of the US origin as much as they can regardless of whether they have trouble with wheat/gluten or not. The occasional use of imported flours may be acceptable if not frequent. Using wheat flour to make fermented breads, such as a sourdough bread, seems less harmful in my experience, but since it is still made of wheat, so you might not want to consume too much.