Endotoxin (Lipopolysaccharide, LPS)

Endotoxin, chemically known as lipopolysaccharide (LPS), is a structural molecule produced by gram-negative intestinal bacteria that Peat identified as a central driver of systemic stress and metabolic dysfunction. 3 It consists of a starch-like polysaccharide chain attached to fatty acids, giving it a soap-like physical action that destabilizes cells upon contact. 3 Peat argued that while textbooks historically claimed endotoxin is only released when bacteria are broken apart, it likely leaks continuously during normal bacterial growth and division. 2 This molecule is so ubiquitous that all animals have evolved innate immune systems to recognize its presence, triggering the release of serotonin, histamine, and nitric oxide as primary defense reactions. 2

Under healthy conditions, the intestinal barrier and liver work in concert to prevent significant amounts of endotoxin from reaching the general circulation. The bile acids, a major end product of cholesterol, act as detergents that keep endotoxin in solution away from the absorptive surfaces of the intestine, while liver enzymes break down any LPS that does enter the portal vein. 2 Peat emphasized that the microscopic integrity of the intestinal cells, protected by a mucus lining, ultimately regulates passage into the blood and lymphatic vessels. 2 However, this barrier is weakened by stress, malnutrition, and reduced circulation, all of which increase intestinal permeability and allow endotoxin to flood the system. 3 Peat specifically noted that estrogen can inhibit bile flow and shut off blood supply to the intestine, directly compromising the body's primary defenses against LPS absorption. 2

Once in the bloodstream, endotoxin becomes a profound metabolic poison that shifts cellular energy production away from efficient oxidative metabolism. Peat explained that LPS and estrogen converge mechanistically by interfering with the metabolic use of oxygen, turning on glycolysis and forcing the conversion of sugar into lactic acid rather than carbon dioxide. 8 This creates a state of reductive stress, where an excess of electrons and insufficient oxygen drive degenerative processes. 8 The liver is particularly vulnerable; high endotoxin levels slow liver function, impairing its ability to detoxify estrogen and other substances, which creates a vicious cycle of increasing estrogen burden and further metabolic suppression. 7 Dinkov has written that endotoxin's degenerative effects, including fibrosis and cancer, are largely driven by activation of the TLR4 receptor, which triggers a downstream cascade of inflammatory mediators. 10 Roddy notes that endotoxin synergizes with and increases the effects of serotonin, histamine, estrogen, and cortisol, while directly decreasing thyroid production and inducing insulin resistance. 11

The production and absorption of endotoxin are heavily influenced by diet and digestive efficiency. Peat taught that poorly digested foods, particularly undercooked cereals, starchy foods, and poorly cooked vegetable material, pass undigested into the lower intestine where they feed the bacteria that produce LPS. 2 In contrast, quickly digested foods like fruit allow sugars and minerals to be absorbed before reaching the bacterial area of the intestine, reducing the substrate for endotoxin production. 2 Peat recommended raw carrots for their bactericidal effect, which suppresses bacterial growth, while their fiber absorbs and stimulates excretion of endotoxin. 8 He also identified calcium as a specific suppressor of the fermentation of fiber and starch, and noted that saturated fats have a germicidal effect that helps keep the intestine relatively sterile. 2 Antibiotics lower endotoxin formation and protect against its induction of serotonin, histamine, estrogen, and cortisol. 1

The systemic consequences of chronic endotoxin absorption extend far beyond the gut. Peat described how a "leaky intestine" allows toxins to enter the general circulation and travel directly to the brain, heart, and lungs, contributing to conditions including obstructive pulmonary disease, emphysema, reduced heart function, heart failure, insomnia, and sleep apnea. 7 He also observed that reverse peristalsis, driven by local irritation in an over-excited, under-energized state, is extremely common and can move material from the rectum to the mouth overnight. 7 Dinkov has highlighted that serum endotoxin levels directly correlate with the severity of liver disease, including NAFLD, NASH, hepatitis, and cirrhosis, and that vitamin E may be a viable tool for preventing and treating the damage endotoxin causes. 10 Peat maintained that a small amount of endotoxin absorption is normal and acts as a stimulant to the immune system, but when liver function slows, it massively breaches the liver's barriers and begins poisoning the entire organism. 2