Lilac
Member
- Joined
- May 6, 2014
- Messages
- 636
Ray has a few articles on fats on his website. I just took another look at this one, and I think it is one of his more easily understood pieces:
"The cheapness of the seed oils led to their use in animal feeds, to promote growth. By the 1940s, the polyunsaturated oils, including fish oils, were known to cause deterioration of the brain, muscles, and gonads in a variety of animals, and this was found to be caused mainly by their destruction of vitamin E. A little later, the disease called steatitis or yellow fat disease was found to be produced in various animals that were fed too much fish or fish oil.
"The reason linseed oil and fish oil were used for making varnishes and paints was that they are "drying oils," reacting with oxygen to polymerize and harden. The physical and chemical propertiess of the oils are fairly well understood, and among the polyunsaturated fatty acids (PUFA) the omega -3 fatty acids react most easily with oxygen. Heat, light, and moisture increase their spontaneous interactions with oxygen, and besides polymerizing, these oils produce a variety of reactive particles, including acrolein, which combine with other substances, such as cellular proteins and DNA, with highly toxic effects. At low temperatures and low oxygen concentrations these oils are not highly reactive. Fats that harden at low temperatures (as saturated fats do) wouldn't be convenient for organisms that live in a cool environment, and so organisms regulate the type of fat they synthesize according to the temperature of their tissues. The fact that certain types of polyunsaturated fatty acids function nicely in fish, worms, and insects, doesn't mean that they are ideal fats for mammals.
"The fact that vitamin E prevented or cured some of the major diseases in farm animals caused by excessive PUFA, and that it could retard the development of rancidity in stored oils, led quickly to the persistent belief that lipid peroxidation is the only toxic effect of the vegetable oils. However, the oils were being seen to cause other problems, including accelerated aging and obesity, but those problems weren't of interest to farmers, who wanted to sell plump young animals as cheaply and quickly as possible. Even fresh oils have toxic effects, and the oxidative damage they do is often the consequence of these other toxic actions.
"Another cheap food additive, coconut oil, was found to increase feed consumption while slowing weight gain, so it wasn't popular in the meat industry. The highly unsaturated seed oils had the opposite effect, of producing a rapid fattening of the animal, while decreasing feed consumption, so by 1950 corn and soybeans were widely considered to be optimal feeds for maximizing profits in the production of meat animals. It was at this time that the industry found that it could market the liquid oils directly to consumers, as health-promoting foods, without bothering to turn them into solid shortening or margarine. Somehow, few physiologists continued to think about the implications of metabolic slowing, obesity, and the related degenerative diseases."
