[To quote]
Experimental evidence suggests a component of a B-complex vitamin
may be needed to maintain adequate HCl secretion. It has been
demonstrated that a diet inadequate in the entire B-complex impaired
gastric secretion in experimental animals. This effect was
reversible upon administration of a diet supplemented with B
vitamins.

Cholinergic drugs stimulate production of acid and anticholinergic
drugs inhibit it. HCl production is usually increased by caffeine,

alcohol, histamine, and hypoglycemia. The production of pepsin is
actively stimulated by any stimulant that increases HCl.31

Historically, beyond the direct administration of HCl, several other
substances were believed to stimulate either acid secretion or
digestion. These include the use of diluted lemon or vinegar prior
to meals; the use of herbal bitters, such as Centaurium minus or
erythraea (common or red centaury), Gentiana lutea, (gentian), and
Zingiber officinale (ginger); and the use of stimulants such as
Piper nigrum (black pepper) and Capsicum annum (cayenne). While
there is a little research on the majority of these substances, the
bitter principles of the dried underground organs of Gentiana lutea
have been shown to stimulate gustatory receptors in the taste buds,
causing a reflex increase in the secretion of saliva and gastric
juice. [Note: Watkins has ginger and piper nigrum (black pepper) in
all of their dietary supplements]

Skin Diseases: The preponderance of information on gastric acid
secretion, HCl supplementation and skin disease is based on the work
of Allison published in 1945. In Allison’s experience, a normal
balance of gastric acidity could be restored with administration of
HCl during meals. In severe cases he recommended one capsule of HCl
before, during, and after each meal. He was convinced, in severe
hypochlorhydria or achlorhydria, B-complex vitamins were poorly
absorbed. In patients known to be or suspected to be vitamin B-
complex deficient, he invariably found achlorhydria or
hypochlorhydria. In certain cases, he observed distinct psychic
influences (primarily anxiety and nervousness) seemed to suppress
acid secretion.

All/Best,
Dan