Cholesterol

Cholesterol is the fundamental sterol molecule in animals, serving as the essential raw material that is massively converted into steroid hormones, a process requiring thyroid hormone and vitamin A. 1 Peat argued that cholesterol is not merely a membrane component but is distributed throughout the cell, associated with chromosomes and the cytoskeleton, where it stabilizes structure and enables normal cell division. 3 He emphasized that cholesterol acts as a broad-spectrum protective substance, an anti-stress hormone that can neutralize toxins and protect red blood cells from disintegration under stresses like hyperthermia. 2

The synthesis and regulation of cholesterol are intimately tied to metabolic rate. Peat explained that hypothyroidism directly causes serum cholesterol to rise as metabolism slows, and that thyroid supplementation normalizes it by facilitating the conversion of cholesterol into protective steroids and bile salts. 5 He noted that a healthy liver, given adequate energy from sugars and minerals, can produce sufficient cholesterol, and that dietary intake has little effect on blood levels in healthy individuals. 7 When an organism is stressed, cholesterol elevates adaptively to provide the precursor for pregnenolone and downstream defensive steroids; a chronically high level often indicates a conversion issue where the thyroid-driven transformation into these hormones is impaired. 2

Peat consistently challenged the dogma that high cholesterol is a primary cause of disease, citing evidence that it is protective for longevity and cognition. He referenced a nursing home study where the optimal cholesterol for longevity was 270 mg/dL, and the Framingham study showing that levels below 200 mg/dL after age 50 were associated with a sharply higher incidence of dementia. 3 He pointed out that the inflammatory nature of atherosclerosis was clear to early pathologists, and that the real culprit in plaque formation is the oxidation of polyunsaturated fatty acids (PUFA), whose breakdown products attract macrophages and degrade the ABCA1 protein responsible for cholesterol removal. 2 The "foam cells" in plaques are filled with oxidized lipids, not simply cholesterol. 10

The lipoprotein carriers of cholesterol have been mischaracterized by mainstream medicine. Peat stated that LDL, often labeled "bad cholesterol," is extremely good because it serves as the direct source for producing progesterone and DHEA. 4 He noted that the HDL/LDL ratio suggesting freedom from heart disease conversely suggests susceptibility to cancer, and that deliberately interfering with cholesterol synthesis with drugs like statins is biologically catastrophic, as it makes it impossible to produce essential brain steroids. 3 Early trials of cholesterol-lowering interventions were halted when they revealed increased cancer mortality in the treatment groups. 8

At a cellular level, cholesterol functions as both a lubricant and a stabilizer of the protoplasmic solution, decreasing cell rigidity by increasing protein mobility. 10 It is essential for the organized interactions between DNA and the nuclear matrix; experimental cholesterol starvation arrests cell division in a tetraploid state, a precursor to aneuploidy and cancer. 2 In the brain, excitatory stimulation lowers cholesterol, while meaningful environmental enrichment increases it, and the age-related accumulation of cholesterol esters at the expense of free cholesterol contributes to neurodegeneration. 2 Peat concluded that cholesterol's physiological meaning touches on movement, stability, differentiation, memory, and sensitivity—essentially everything physiological. 6