No, it is not always true that erosive duodenum cannot be regenerated. It depends on so many factors. There are many reasons why erosive duodenum may fail to heal. Not taking medications according to directions is one reason. Another is that some types of H. pylori are resistant to antibiotics. Other factors that can interfere with the healing process include regular use of tobacco, alcohol or nonsteroidal anti-inflammatory drugs (NSAIDs). Sometimes the problem is accidental: People are unaware that a medication they're taking contains an NSAID.

In rare cases, it may be a result of:

*Extreme overproduction of stomach acid, such as occurs in Zollinger-Ellison syndrome (It is a complex condition in which one or more tumors form in the pancreas or in the upper part of the small intestine (duodenum). These tumors, called gastrinomas, secrete large amounts of the hormone gastrin, which causes excessive production of acid by your stomach. The excess acid, in turn, leads to peptic ulcers.)

*An infection other than H. pylori

*Other digestive diseases, including Crohn's disease or cancer

Yes, it is confirmed by the researchers that peptic ulcer patients who drank  4 glasses or 1 liter of raw cabbage juice(its high content of glutamine and S-methylmethionine, an amino acid that is the preferred fuel for the cells that line the stomach and small intestine) daily were healed in between 4 and 10 days .

Diet for diet for people with duodenitis problems / Ulcer patient:

The pain experienced by people who have ulcers is caused by the open sore coming into contact with acidic digestive juices. When food is ingested it can bring temporary relief from the pain as the acids are neutralised by the food but the pain returns after the food is digested.
In the past, physicians advised people with ulcers to avoid spicy, fatty, or acidic foods. However, a bland diet is now known to be ineffective for treating or avoiding ulcers. No particular diet is helpful for most ulcer patients. People who find that certain foods cause irritation should discuss the problem with their physicians.
Smoking has been shown to delay ulcer healing and has been linked to ulcer recurrence; therefore, people with ulcers should not smoke.

Now that my wife had her colonoscopia made and no lateral problems have been discovered the doctor told her to keep taking Omeprazol. In ten month she's going to have another endoscopia to check the condition of the duodenum. I bought her 350g of Glutamina, hoping that it will help to heal her duodenum. She's 71 and otherwise pretty healthy. Not smoking, taking alcohol or spicy foods. It seems all getting fine.