Author: Heidi du Preez
Fats and oils in their natural form provide numerous health benefits, but processing methods turn fats that heal into fats that kill. There are three main categories of processes that commercial vegetable oils undergo:
- Hydrogenation turns liquid oils into cheap, plastic, spreadable, shelf-stable fats. This process changes fatty acids into twisted molecules called trans-fatty acids that have never existed in nature. They are found in margarines, shortenings, partially hydrogenated vegetable oils and vegetable shortenings. Research studies show that trans-fatty acids can lead to cardiovascular disease and cancer, interfere with immune function, decrease testosterone, increase abnormal sperm and interfere with pregnancy in animals. They also correlate with low birth weight in babies, interfere with blood insulin function and interfere with liver enzymes necessary for detoxification.
- Frying Research consistently shows that fried fats cause cancer and hardening of the arteries. The chemistry of oil molecules changes when we heat oils. The chemically-altered molecules do not fit into the precise biochemical architecture of our body. They therefore interfere with how our cells function, which we experience as health problems. The oils best for our health, those richest in the essential fatty acids, become most toxic when fried. However, frying temperatures also damage hard, stable, saturated tropical fats and butter.
- Refining and deodorising produces colourless, odourless, tasteless and almost completely nutrition less oils. These oils are refined and therefore are the equivalent of white sugar or white flour, where most of the nutrients required for human health have been removed.
Except for extra-virgin olive oils and certain cold-pressed oils, which remain unrefined and undeodorised, all oils that line supermarket shelves have gone through processing where they are subjected to several harsh treatments. Processed fats and oils are:
- Degummed – treated with sodium hydroxide, an extremely corrosive base also used to clean clogged kitchen sink drains;
- Refined – treated with phosphoric acid, an extremely corrosive acid;
- Bleached – this produces rancidity (peroxides), which imparts unpleasant odours and tastes to oils; and,
- Deodorised – heated to above frying temperatures to remove the peroxides produced by bleaching. The taste becomes less objectionable, but other chemical changes, tasteless but toxic, take place at such high temperatures.
During these processes, some of the fatty acid molecules are destroyed or changed chemically into toxic molecules that interfere with normal biochemical interactions, thus interfering with health. When oils rich in essential fatty acids are heated above 150°C, they change from being protective against cancer to cancer-causing. Other phytochemicals, which have major benefits on health, are also removed or destroyed.
All mass-market refined oils, even canola and grapeseed oil, are nutrient-poor and therefore not good oils to use.