HCL "[optimizes] the immune system gut flora"

This is important . . . , but always, always take these claims with your most judicious caveat.  The article begins thus, 

We all know that eating a healthy, balanced, natural diet is a cornerstone of perfect health, but what if all of that nutritious food is not being processed efficiently? 

It opens with a statement that we've all just accepted as a prevailing truth because that point has been droned into our heads for decades, a statement that, in my opinion, tends to benefit the vitamin supplement industry.  Important to eat a "healthy, balanced, natural diet," yes, but what does that even look like?  I mean who can dispute such a fact?  And then that statement of fact ends ominously with a worrisome question, ". . . but what if all of that nutritious food is not being processed efficiently?" For one, at least in America, food is cheap.  Even for people who can afford to eat better than the average American, they still consume junk--fast food, snack food, sweets, etc., in other words, junk.  So the article opens on a dubious premise.  It then proceeds to answer its own question,

Betaine hydrochloride, derived from beets, is a supplement for helping food to be fully dissolved and processed in the stomach for optimum nutritional benefits.

". . . derived from beets"!!  Wow!  It must be okay then.  And I am sure it is.  It's just that the author is looking for some kind of authority, and since beets is a natural food grown in the earth, who can question the nutritious value of beets?  I love beets.  Have eaten them raw and pickled in a syrupy sauce, the way they used to be sold for years.  My mom loved beets.  A supplement derived from beets?  Even safer, right?  Maybe.  I am not disputing the benefits of Betaine Hydrochloride.  It think it is beneficial for folks with gastro-intestinal problems.  I have tried Betaine Hydrochloried, and I noticed several benefits.  However, I am not convinced that one should try as much as they like or for as long as they like.  Short-term in small amounts might be judiciously advised.  

The stomach processes food both mechanically and chemically by breaking it down with hydrochloric acid into its basic constituents, which are then forwarded to the digestive system and blood for nutritional distribution

That's a good point.  It's good to imagine how the muscles of your stomach and its lining are mechanically employed to break food down. And chemically, of course.  But this article poses concerns that stem from digestive inefficiency by the stomach muscles and its chemical, hydrochloric acid.   

If food is not processed effectively by the stomach, it is as if the body is being starved of a healthy diet with the same potential health consequences due to an inefficient or sub-optimal immune system. All disease arises from either low immunity, abnormal immunity or auto-immunity, including cancer, the immune system as a whole being ultimately dependent on gut flora of the stomach and digestive tract.

Okay, some important facts here that can be extrapolated from the sales pitch.  It's true that "the immune system as a whole [is] dependent on gut flora of the stomach and digestive tract."  Which only blows me away when I think how hospitals when they admit patients will flood a patient's body without question or a single regard for their condition with antibiotics that absolutely destroy gut flora, thereby weakening the patient and priming them for doctor-prescribed medicine while they are laid up, getting weaker and sicker in the hospital.  The pharmaceutical industry has for the most part been the agency that has promoted doctors and built their respectable reputation.  But be careful with that; they don't always deserve your unexamined respect.  These guys have peddled antibiotics to people with virus infections, and yet they never offer a sound, logical explanation for prescribing such an irrational remedy.

The article was doing just fine until it reaches into its bag of industry-standard scaremongering, 

Research has shown that, after the age of 21 years, the concentration of hydrochloric acid in the stomach begins to fall progressively with age, a condition known as "hypochlorhydria."

Oh, so now we have a new condition, one that I have never heard of. One, your body has amazing compensatory, feedback mechanisms to keep you alive despite horrible assaults and insults to your biology.  To cite the age of 21, a time when most people are just developing and coming into their own, as the age when people are in decline is absurd.  I had a doctor tell me once, following a short-term bout of declining energy, that I was at that age when things begin to fail.  I stood there with a fixed stare like I was listening to some sorcerer standing in front of an inscrutable sphinx. For men, and I would also say for women, your 40s are some of your best years, but this article contradicts my observation,

By the time people reach the age of 40 or 50, stomach hydrochloric acid concentration is much lower and attributable to age-related immune and auto-immune conditions, including diabetes, cancer and obesity--particularly abdominal fat--hence the so-called "middle age spread." Use of betaine hydrochloride has frequently been credited with flattening the stomach for this reason.

Now that is miraculous.  Using Betaine Hydrochloride can get rid of belly fat.  Actually, it can.  I lost 5 pounds while using the stuff for about ten days.  I just can't say with any certainty that it was a healthy weight loss. Can't say either that it wasn't.  My blood tests came back clean.  Except that I need to drink more water.  I am getting enough protein; didn't think there was a problem with that, but it was nice to hear from the doctor that my blood was good.  He said "You're like Brad Pitt."  I laughed.

The article does note that acid reflux is caused by lactic acid, not hydrochloric acid rising from your stomach up into your esophagus:

Acid reflux is caused by lactic acid, a warning sign for too low of a concentration of hydrochloric acid, causing incomplete digestion of food. Acid reflux needs to be treated by increasing hydrochloric acid, not antacids which will neutralize hydrochloric acid, making reflux worse as well as other health consequences.

That has the ring of truth to it.  

Low hydrochloric acid is a potential cause of cancer and other immune and auto-immune conditions.

Everyone, without exception, has cancer genes, "oncogenes," circulating around the body. These cancer genes are normally kept in check by a healthy immune system, but in the case of cancer, the immune system can no longer suppress the cancer genes, which can then get out of control and multiply. The immune system responds by forming a tumor to contain the malignant cancer cells.

Chemotherapy may suppress cancer cells temporarily but also destroys the immune system, exposing the patient to a very wide range of additional diseases as well as additional types of cancer through immune-suppressed cancer gene expression.

If the "Th1" immune system is compromised or disabled, the "Th2" component of the immune system attempts to take over. Th2, not being equipped to function as Th1, perceives genuine body tissues as foreign invaders, attacking them as it would a bacterium or virus. Th1 suppression is also a root cause of auto-immune diseases such as allergies, celiac disease and arthritis.

How Betaine HCl supplementation can bring valuable health benefits:

Betaine hydrochloride (betaine HCl) increases the concentration of hydrochloric acid in the stomach relative to how much is taken before meals. This enables the stomach to much more completely dissolve and process foods right down to base nutrients, as well as produce methyl groups, an important element in preventing cancer and other diseases.

Taking betaine HCl before meals helps the stomach make optimum use of all dietary nutrients, also optimizing the immune system gut flora, without which, even with a healthy diet, many diseases including cancer can arise and propagate.

Low hydrochloric acid is related to other serious ailments.  See here.