I have been reading through Jan Kwasniewski’s book Homo Optimus and came across this bit:
Those who are not interested can skip the next few lines, but I would like to explain these processes which lead to advantageous or harmful changes in our bodies. Unsaturated fats, we are told – essential unsaturated fats – are present in mother’s milk at the concentration of 0.4%. No one can dispute that mother’s milk is the ideal nutrition, as far as the biochemical composition is concerned. It contains 3 to [illegible] grams of fat per 1 gram of protein. The conclusion is obvious – if Nature included such a minute quantity of that constituent in such a wonder food, then we should respect it. Meanwhile, people are being persuaded that plant-derived fats containing polyunsaturated fatty acids which do not exist in mother’s milk, are healthy. Nothing is more misleading – in the body they participate in reaction by binding oxygen. Peroxides, superoxides, various other poisons accelerating the formation of atherosclerosis are formed; aging of tissues, mechanical damage, cancer formation occurs. Some time ago, experiments were conducted investigating the effects of the replacement in a diet of saturated fat with unsaturated fats. What was concluded? Patients who were fed unsaturated fats were getting cancer 3-4, even 5 times more often than patients on the same proportion of saturated fats. Its is obvious why. Peroxides, which I have already mentioned, induce inflammations in the body, disease states, they simply degenerate tissues and whole organs. This concerns polyunsaturated fats only, those not present in butter, but instead present in plant-derived oils. That is not the end to it. In the bodies nourished with polyunsaturated fat the chemical compound called malate aldehyde is formed – terrible stuff. Technical gases such as ethane and pentane are also formed, excreted by the body, defending itself against the poisoning. However, together with these gases we also excrete hydrogen – the best fuel for our tissues.
I like that he mentions the aldehydes produced when polyunsaturated fats are oxidized. As he says, “terrible stuff”.