Foods & Substances
Unsaturated oils
When an oil is saturated, that means that the molecule has all the hydrogen atoms it can hold. Unsaturation means that some hydrogen atoms have been removed, and this opens the structure of the molecule in a way that makes it susceptible to attack by free radicals.
Unsaturated oils are fats whose molecular structure lacks hydrogen atoms, creating a chemical openness that makes them susceptible to attack by free radicals. Peat argued that this vulnerability initiates lipid peroxidation, a chain reaction of oxidative damage that spreads within cells and contributes directly to aging. The toxicity is intrinsic to the polyunsaturated fat itself, not a byproduct of industrial processing; these oils are found in high concentrations in seeds like soybean, corn, safflower, canola, and sunflower, and they accumulate in the tissues of animals fed these seeds.
Peat identified two evolutionary reasons for their harmfulness. First, plants produce these oils as defensive toxins to block the proteolytic digestive enzymes in the stomachs of animals that eat the seeds, which means they fundamentally disrupt protein digestion and all systems evolutionarily derived from it, including thyroid hormone production, clot removal, and immunity. Second, the oils are designed to remain liquid at the low temperatures of early spring germination, but they become highly unstable and spontaneously oxidize when warm and exposed to oxygen inside the body, causing them to go rancid. This oxidative stress damages mitochondria, suppressing the respiratory enzyme and uncoupling energy production, which lowers the metabolic rate and creates a hypothyroid state that promotes obesity. Peat noted that the agricultural industry discovered that corn and soy beans had an antithyroid effect that fattened livestock cheaply, and these same oils were subsequently marketed for human consumption.
The systemic consequences of excess unsaturated oil consumption include immunodeficiency, inflammation, abnormal clotting, cancer, and brain damage. Peat cited experiments showing that pregnant mice fed unsaturated oil produced offspring with smaller brains and inferior intelligence, while nursing rats fed soy oil incorporated it directly into brain cells, causing visible structural abnormalities. He also emphasized that dietary linoleic acid is required for the development of alcoholic liver damage, and that unsaturated oils promote the formation of age pigment (lipofuscin). The oils weaken red blood cell structure through lipid peroxidation, causing premature destruction, and their breakdown products act as chaotropic agents that create structural disorder in cell surfaces.
Peat rejected the concept of "essential fatty acids" as a misnomer, stating that the body can synthesize its own unsaturated fats when dietary linoleic and linolenic acids are absent. He also dismissed the claim that unsaturated oils are needed for membrane fluidity, arguing instead that their affinity for binding to proteins—particularly proteolytic and respiration-related enzymes—accounts for their toxicity, and that saturated fats like those in coconut oil can actually increase fluidity in certain cell types, such as lung alveolar cells. The harm from these oils is governed not by absolute quantity but by the relationship between them and saturated fats in the diet. Peat recommended strict avoidance of soybean, corn, safflower, flax, cottonseed, canola, peanut, and sesame oils, and noted that even lard from corn-and-soy-fed pigs is chemically equivalent to vegetable oil and equally toxic.
People also ask
- How do unsaturated oils cause oxidative damage in the body?Peat argued that their molecular structure lacks hydrogen atoms, making them susceptible to free radical attack, which initiates lipid peroxidation—a chain reaction of oxidative damage that spreads within cells and contributes to aging.
- Why did Peat believe unsaturated oils suppress thyroid function?Peat explained that these oils disrupt proteolytic digestive enzymes, impairing systems evolutionarily derived from them, including thyroid hormone production, while their oxidative stress damages mitochondria and lowers metabolic rate, creating a hypothyroid state.
- What is the relationship between unsaturated and saturated fats in the diet?Peat stated that the harm from unsaturated oils is governed not by absolute quantity but by their relationship with saturated fats, and he recommended strict avoidance of common seed oils while noting that saturated fats like coconut oil can increase membrane fluidity.