It's probably not a coincidence that H. pylori lowers stomach acidity. It's trying to feed itself. Lowering stomach acidity promotes poor digestion and extra food for hydrogen gas (H2)- producing bacteria further down the digestive tract. H. pylori thrives on the resulting increase in H2. There are countless examples in nature of parasites manipulating hosts to get what they want. A pretty simple example is Bordetella pertussis, the bacterium that causes whooping cough. It secretes factors that irritate the trachea, causing the victim to cough and thus facilitating its own spread through airborne droplets.
H2 is a high-energy molecule. In fact, it's being considered as an automobile fuel. It's also very small, allowing it to diffuse away from the digestive tract and throughout the tissues. Overproducing H2 in the digestive tract creates an all-you-can-eat buffet for whatever bacteria are present in the body that are capable of using it. As I mentioned in the last post, these bacteria include H. pylori, Salmonella and perhaps Clostridium. Nature abhors a vacuum. I'm sure there are organisms happy to siphon off some of this fuel. The interior of the body is relatively sterile, but there are plenty of bacteria hanging around the mucous membranes (nasal cavity, digestive tract, urogenital tracts) that could potentially exploit this energy source.
How do we thwart H. pylori and take back control of our stomachs? There are a few options. The first is to send in the big guns and take antibiotics. This is the standard treatment and it's usually effective, but I'm generally against antibiotics unless absolutely necessary due to their long-term effects on beneficial gut flora. Then there are other treatments like mastic gum, peppermint, gentian and probiotics, which may or may not be effective.
But the method I like best is starvation (of H. pylori). Obviously, the first step is to eliminate excess fructose, wheat, and anything else that causes digestive upset and gas. Several commenters on the last post mentioned that eating a "paleolithic"-type diet improved their digestion and reduced gas. That makes perfect sense to me, and it may actually be a very important effect of that type of diet. The same goes for low-carbohydrate diets. Two other weapons of intestinal flora starvation are chewing thoroughly and avoiding liquids during meals. The former allows you to absorb the maximum amount of calories from your food as rapidly as possible, leaving less for the bacteria. The latter makes digestion more effective by keeping stomach acid concentrated. A little bit of liquid such as a small glass of wine is probably fine.
If necessary, the next step may be to restore full stomach acidity, further cutting off the supply of H2 to H. pylori and breaking the cycle of reduced acidity, leading to increased H2, leading back to increased H. pylori growth. Sufficient stomach acid may also inhibit H. pylori directly, but there isn't much research on this. Restoring stomach acidity is pretty easy to do using betaine HCl supplements. Many people report improved digestion when they use betaine HCl. These basically release hydrochloric acid into the stomach, lowering pH. Most of them also contain pepsin, a protein-digesting enzyme secreted by the stomach. Buy them in capsule form rather than tablets so they dissolve rapidly.
Ideally, you should have your stomach pH checked to confirm you have insufficient stomach acidity before taking betaine HCl. If it's not lacking, there's no point in taking it (although trying it won't do you any harm beyond a little discomfort). But if you want to skip the expense, there are web pages that can teach you how to use subjective measures to determine if it's helpful for you. Some people feel that the stomach eventually "learns" to produce enough HCl again after a course of betaine HCl, after which they can stop taking it. This may reflect a suppression of H. pylori.
I think it's notable that healthy traditional cultures that ate plant foods didn't do it haphazardly. First of all, they typically ate the minimum amount of fiber necessary to get their calories. If they could remove fiber from their food, they did. For example, ogi is a widespread grain porridge eaten in Western Africa. To make it, you soak millet, corn or sorghum overnight. Then you pound it, mix it with water and strain it through a sieve. This removes the bran but allows most of the suspended starch through. The bran is fed to the animals, while the starch is fermented, cooked and eaten.
This is typical of healthy non-industrial cultures. They don't care about the glycemic index of starches, they care about maximizing digestibility and assimilation. In the process, they are minimizing food for their digestive flora. Fermenting grains before cooking may also reduce the amount of food left for gut bacteria. Starchy tubers and fruit (plantain, breadfruit) are also common features of healthy traditional cultures. They cook them thoroughly, sometimes mash them, and sometimes ferment them as well (e.g., poi).
Low-calorie vegetables are not staple foods in most of the world's healthiest non-industrial cultures, including hunter-gatherers. That's the main reason why I'm skeptical of the claim that eating immoderate quantities of vegetables is essential for health.
I do think it's worth mentioning that although they tried to minimize fiber, many (but not all) healthy non-industrial cultures nevertheless ate a lot of it and did just fine. It was inescapable for many of them. If you don't have the technology to remove rice bran, you have to eat it along with the starch. It may be just as well. Bran carries a disproportionate amount of vitamins and minerals. But it also comes along with a disproportionate share of toxins, which must be inactivated prior to eating by soaking, sprouting or fermentation. Healthy grain-based cultures knew this well, but we seem to have forgotten it in modern times.