Hydrochloric Acid

Aajonus drew a critical and frequently stated distinction between how carnivores such as dogs and cats produce hydrochloric acid and how humans produce it. Carnivores concentrate 15 times the amount of hydrochloric acid in the stomach itself, relative to humans. Their intestinal tracts are short, roughly three times the length of their torso, and they digest meat in 10 to 14 hours. Humans produce a smaller concentration of hydrochloric acid in the stomach but secrete it continuously throughout the entire length of the small intestine, so that when the total amount produced across the stomach and intestines is compared to that of a dog or cat, the quantities are roughly equivalent.

This distributed production pattern explains why humans have a much longer digestive process. Meat takes 19 to 24 hours to move through the human digestive tract fully, compared to 10 hours in dogs and cats. The long human intestinal tract, which Aajonus stated is approximately 112 times the length of the torso, gives the body time to secrete hydrochloric acid gradually along the way and to saturate the food with bacteria at each stage.

Within the stomach itself, Aajonus described two functional compartments. The first compartment is where the bulk of the stomach's hydrochloric acid is secreted into the food, beginning the dissolution of large protein-based chunks. The second compartment, the duodenum, is where bile enters from the gallbladder and begins breaking down fats. These two processes, hydrochloric acid on proteins and bile on fats, operate in sequence, with the hydrochloric acid phase preceding the bile phase.

The intestinal wall itself can also generate hydrochloric acid on demand. Aajonus described a sensing mechanism in which the villi of the small intestine register the size of food particles passing by them. If particles remain too large, signals are sent to produce additional hydrochloric acid to continue breaking them down so bacteria can eat them. Bile is also transported via the lymphatic system to various locations along the intestinal tract to assist with fats that were not fully processed in the duodenum.

Aajonus used the word putrefactive repeatedly to describe the character of human hydrochloric acid, meaning it is designed to work on animal-derived matter. The bacteria present in the mouth and stomach also have a putrefactive character, meaning they are adapted to digesting animal cells, whether meat, dairy, or eggs, and have little productive interaction with vegetation, fruit, or grains. He distinguished this from the hydrochloric acid of herbivores such as cows and sheep, whose stomach acids are designed to break down the proteins locked inside cellulose walls.

When vegetation is consumed and passes through the human intestinal tract, its alkaline secretions neutralize hydrochloric acid and disrupt the acidic bacterial environment. The intestinal pH must remain in a range of approximately 4.9 to 5.2 for hydrochloric acid to function and for acid-bearing bacteria such as salmonella, listeria, campylobacter, and E. coli to operate properly. When vegetable matter raises the intestinal pH to around 6, hydrochloric acid can no longer dissolve food particles efficiently, and the bacteria cannot digest protein effectively.

This is why Aajonus gave qualified instructions about how to incorporate vegetable juice into the diet without neutralizing the digestive environment. Vegetable juice, as opposed to whole vegetables, passes into the stomach and moves quickly into the duodenum without triggering hydrochloric acid secretion, because it contains virtually no protein. The small amount of fat in vegetable juice is handled by a small amount of bile, and whatever trace pulp makes it through is insufficient to cause indigestion. Whole vegetables, by contrast, send alkaline secretions throughout the intestines as they transit, suppressing the acid-bacteria system that digests meat and dairy.

Aajonus was explicit about how much hydrochloric acid different foods require, and this forms a practical framework for understanding why food preparation and food combining matter in the Primal Diet.

Eggs require no hydrochloric acid at all. Because an egg is already in liquid form, bacteria can infiltrate it immediately without any preliminary dissolution. Aajonus stated that an egg digests in 27 minutes, the fastest of any food. He emphasized this point by describing how he would suck an egg into his mouth and move it around to mix it thoroughly with salivary bacteria before swallowing, allowing bacterial digestion to begin immediately with no requirement for the dissolving action of hydrochloric acid.

Milk requires very little hydrochloric acid but does require significant time. Raw milk, Aajonus said, takes 6 to 16 hours to digest, depending on the version of the statement, because its proteins must still be broken down despite the fact that the liquid form reduces the burden on hydrochloric acid.

Meat requires substantial amounts of hydrochloric acid when consumed in chunks or pieces of significant size. The bacteria can only penetrate the outer layers of a thick slice, so the acid must dissolve the interior before bacteria can reach it. This is why meat takes 19 to 24 hours to move through the digestive tract.

However, if meat is completely minced, ground to a paste, or pated in a food processor until the particles are liquid in consistency, the need for hydrochloric acid is greatly reduced or eliminated entirely. Aajonus was explicit about this based on his own experience. Because of his vagotomy, which severed all vagus nerves to his stomach and eliminated his gastric hydrochloric acid production, he could not dissolve meat chunks and had to consume meat in very small pieces or ground and pated form so that his intestinal hydrochloric acid, which continued to function, could manage the load. He observed that eating meat pated reduced his sleep requirement to 3.5 hours per day, whereas eating meat in chunks that he had chewed thoroughly still required him to sleep an hour to an hour and a half more per day, because the additional digestive work consumed energy.

Nuts contain up to 20 percent protein, and grains contain a maximum of 15 percent protein, but Aajonus argued that the entire apparatus of human hydrochloric acid production to deal with those small percentages of protein made no biological sense, especially since the acid had essentially no effect on the cellulose or plant-cell walls containing that protein. The efficient use of such a robust digestive acid against a substrate it barely affects would be evolutionarily irrational, which he took as further evidence that the system evolved for meat and dairy consumption.

Avocado and coconut are the only plant foods that Aajonus observed the human hydrochloric acid working on meaningfully, though still not as completely as on animal products.

A common medical and popular claim Aajonus addressed repeatedly is that stomach acid destroys ingested bacteria. He flatly rejected this for the body's own resident bacteria. In his experiments, food extracted from the stomach before it entered the small intestine and examined under a microscope showed bacteria still alive and active despite having been bathed in hydrochloric acid. He stated that the body's own bacteria and the hydrochloric acid work together as a coordinated system, not in opposition. The hydrochloric acid dissolves large particles, and then the bacteria move into the dissolved and smaller material to digest it.

He also noted a timing element: hydrochloric acid and bacteria do not work optimally at precisely the same moment. There is a necessary lapse in which the acid performs its dissolution first, and then the bacteria move in afterward. They can work in proximity to each other but need some sequential separation to function at their best.

Digestion in the small intestine is approximately 90 percent bacterial when the gut is healthy, meaning the person has not been treated with antibiotics and does not carry large amounts of accumulated poisons in the stomach and intestines. The remaining 10 percent of digestion is handled by the body's own secreted juices, including hydrochloric acid and bile. Campylobacter, which Aajonus mentioned as a normal resident of the stomach environment, is one of the bacteria present in the stomach alongside hydrochloric acid that assists in the digestive process.

Separate from its digestive role, Aajonus gave extensive detail about hydrochloric acid's capacity to neutralize venoms and poisons. He described the body's natural mechanism of routing toxins to the stomach so that hydrochloric acid can be produced in response. Nausea is always, in his framework, the body's signal that poisons are being dumped from the blood, neurological fluids, or stomach lining into the stomach for neutralization, and the nausea itself reflects the body's production of hydrochloric acid in response to that influx.

He stated that hydrochloric acid neutralizes any venom, from snakes, scorpions, spiders, tarantulas, bees, wasps, or any other venomous creature, without exception. He described the conventional medical production of antivenoms as an elaborate and expensive process that ultimately relies on essentially the same chemistry that hydrochloric acid provides naturally, and he argued that the entire antivenin industry could be replaced by the simpler intervention of inducing vomiting to release concentrated hydrochloric acid.

Aajonus described using this principle on himself when bitten by a rattlesnake. His leg swelled to a size he compared to elephantiasis. He forced himself to vomit, extracted the hydrochloric acid that came up, drew it into a hypodermic syringe, and injected it directly into the swollen leg. The swelling resolved within five hours. He had also tested the principle on another person bitten by a rattlesnake, in that case using beet juice, which he described as high in hydrochloric acid naturally, along with topical application, to neutralize the venom.

He described raw beet juice and raw corn, particularly starchy feed corn, as foods that are high in hydrochloric acid and can be used to supply it when the body's own vomiting response is not possible or available.

The poison neutralization mechanism also explains why, in Aajonus's framework, nausea during detoxification is not a bad sign. The body is intentionally directing poisons to the stomach so that hydrochloric acid can be produced and deployed against them. Suppressing nausea with antacids or Maalox, which he described as essentially liquid chalk, prevents that neutralization from occurring and allows the poisons to remain active in the body.

Aajonus addressed the use of MMS (sodium chlorite, a chlorine-based compound) and noted that because hydrochloric acid is itself a chlorine-containing compound, the body can use chlorine-rich materials to form hydrochloric acid internally. He stated that most bodies will utilize the chlorine and sodium in MMS to form hydrochloric acid, which then acts as a solvent. In the stomach and intestines, this means it dissolves large protein-based food chunks so that intestinal bacteria can penetrate and eat them. He noted that isolated and concentrated chlorine is a solvent that dissolves most substances it contacts, with the exception of digestive and lymphatic tissues.

Because nausea reflects the stomach's production of hydrochloric acid against poisons, Aajonus gave specific guidance about how to work with that process rather than suppress it. When nausea occurs, the body is dumping poisons from the stomach lining or bloodstream into the stomach cavity. Hydrochloric acid is produced to neutralize those poisons, but the neutralized byproducts still need to be absorbed or eliminated.

Cheese, in his protocol, absorbs poisons that are dumped into the stomach, drawing them into its mineral matrix. If poisons are absorbed by cheese before the body must resort to producing hydrochloric acid to neutralize them, the body is spared the metabolic cost of manufacturing and secreting the acid. This is why Aajonus recommended small amounts of cheese, sometimes as small as a sugar cube or half a teaspoon, eaten every 15 minutes during periods of frequent nausea.

The timing protocol he described for cheese before meals works along the same lines. Eating a small piece of cheese and then waiting 10 minutes before eating a meal causes the stomach to dump its accumulated toxins into that cheese alone, since the stomach stops dumping poisons approximately 10 minutes after eating. Then, when the meal is eaten approximately 10 to 25 minutes after the cheese, the stomach is no longer actively dumping toxins into the food, and the hydrochloric acid that is secreted during the meal is devoted to digestive rather than neutralization work.

He also noted that vegetable juice consumed as the last food of the day, particularly before bed, can neutralize the acid environment in the intestines overnight, so that upon waking the system has returned to an acid-capable state, ready to digest whatever is eaten next.

Aajonus described the intestinal environment as needing to remain in a range of approximately pH 4.9 to 5.2 to allow hydrochloric acid to work and acid-bearing bacteria to function. When vegetable matter is present and releasing alkaline secretions, the pH rises to approximately 6, at which point hydrochloric acid ceases to dissolve food particles efficiently, the bacteria cannot eat because their acid-dependent chemistry is disrupted, and protein digestion effectively stops. This is why consuming large amounts of vegetables with meat creates indigestion and incomplete protein breakdown in Aajonus's framework.

Aajonus's personal medical history is woven through almost every discussion of hydrochloric acid in his lectures. At approximately 19 years old, he developed a stomach ulcer, for which doctors prescribed Maalox at doses as high as two bottles per week. The Maalox suppressed acid production, which prevented the ulcer from healing and led instead to the formation of a cancerous tumor adjacent to the ulcer. Doctors then performed what they called a vagotomy pyloroplasty, which severed all the vagus nerves to his stomach, eliminating his ability to produce gastric hydrochloric acid for the rest of his life. They also stretched his duodenum to three times its normal size. He was placed in the category of octogenarians who cannot produce hydrochloric acid and was told he would be in danger of death from bacterial and parasitical contamination if he ever ate anything raw.

After beginning the Primal Diet years later, he ate raw meat, raw dairy, raw eggs, parasite-infested meat, and fecal matter from various animals without contracting parasites or experiencing the bacterial harm he had been warned about. His doctors repeatedly attributed his apparent safety to his hydrochloric acid, until he reminded them that he had none in his stomach. The point he made repeatedly from this personal experience was that the body's hydrochloric acid throughout the small intestine, combined with the resident bacterial population, is sufficient to handle digestion and pathogen management even without the gastric concentration, provided the foods consumed are raw and the diet is appropriate.

He also noted that his lack of gastric hydrochloric acid made him a direct test case for another commonly stated fear, that raw bacteria or parasites in food would overwhelm a person without sufficient stomach acid. His lived experience of eating high meat, fermented foods, and raw animal products without illness while lacking gastric acid production was, in his view, the clearest possible refutation of that claim.

Because he had no gastric hydrochloric acid, he adapted his food preparation to reduce the burden on his intestinal hydrochloric acid. He ground and pated his meat into fine particles rather than eating chunks, because without stomach acid to dissolve large pieces, he needed to mechanically reduce particle size before swallowing. He described ripping meat into very small pieces manually as his practice. He observed that when he did this consistently and ate approximately one pound of meat per day in two meals, he healed rapidly.

He also observed that eating a primarily egg-based diet caused his blood and urine analysis to show a reduction in chlorine levels, which he connected to reduced hydrochloric acid production. Since eggs require no hydrochloric acid, the body produces less of it when eggs are the dominant food, which he noted was not necessarily a problem but was a measurable effect. He also observed that people who produce robust hydrochloric acid do not typically show red urine after consuming beet juice, because the acid breaks down the beet pigments before they can be absorbed, whereas people with reduced hydrochloric acid production, like himself, will show strong pink or red coloring in their urine after eating beets.

The practical implications Aajonus drew from the mechanics of hydrochloric acid are concrete. Chewing meat until it is completely minced eliminates the need for hydrochloric acid, because the mechanical reduction performed in the mouth accomplishes the same dissolution that acid would perform in the stomach. Running meat through a food processor until it is pated to a fine paste accomplishes the same result with less effort. Both approaches allow bacteria to immediately infiltrate the food without waiting for acid dissolution, speeding up digestion, reducing energy expenditure, and reducing sleep requirements.

When food is consumed in large chunks, hydrochloric acid must work throughout the entire length of the intestinal tract, and some portion of the food will reach the end of the intestine without being fully digested, exiting in the feces. This is a direct function of insufficient acid time relative to particle size, not a failure of the digestive system per se, but a consequence of food particle size exceeding what the acid-bacteria system can fully process in the available length and transit time of the intestine.

Swallowing food in large chunks as dogs and cats do is, in his framework, only safe and efficient when the gastric hydrochloric acid concentration is 15 times higher than the human stomach produces, as it is in carnivores. Humans who swallow large chunks are essentially trying to run a carnivore's digestive chemistry with one-fifteenth the available stomach acid, which results in incomplete digestion even with the additional intestinal secretions.

Aajonus described his own ulcer as a failure of the stomach's mucous lining rather than an overproduction of hydrochloric acid. The stomach's lining manufactures hydrochloric acid and, under normal conditions, the lining itself is not dissolved by the acid because it is the most resilient tissue in the human body. When the mucous lining is insufficient, the hydrochloric acid can reach and damage the stomach wall, creating an ulcer. The conventional response of prescribing Maalox neutralizes the acid and stops the erosion temporarily but also completely prevents protein digestion, which over time leads to deficiency and other problems. His argument was that the appropriate response to an ulcer is to support mucus production so the lining can protect itself, not to eliminate acid production.

The surgical remedy he received, severing the vagus nerves, permanently eliminated gastric acid production on the theory that no acid means no ulcer erosion. While technically true, the consequence was the elimination of normal protein digestion capacity and the beginning of the cascade of problems he spent years recovering from through the Primal Diet.