Not just Trans Fats. Cooking oils can contain toxins too
Now that everyone knows that Trans Fats are bad (they were recently banned in New York restaurants) everyone is scrambling to use refined oils for cooking as refined oils do not contain Trans Fats. But if cooking oils are re-heated repeatedly they produce toxins which can be as bad as Trans Fats.
A study was conducted last year which showed that a toxin (4-hydroxy-trans-2-nonenal – HNE), forms when oils like canola, corn, soybean and sunflower are re-heated. Unfortunately it is the healthy oils (Polyunsaturated) which are more susceptible to this problem.That HNE is a dangerous toxin has been proved time and again as it has been linked to heart disease, stroke, liver diseases and also diseases like Parkinson’s, Alzheimer’s and cancer.
The lead researcher of this study is A. Saari Csallany, a professor of food chemistry and nutritional biochemistry at the University of Minnesota. After this study, the American Dietetic Association has advised people not to re-use oil.
Also, according to this article, trans fats are often formed while frying. There is something called Acrylamides. They are often created while frying starchy foods on high heat and a Swedish study has proved that acrylamides cause cancer in rats. Further research on this is being done, mainly to confirm that acrylamides cause cancer in humans.
Which means that we cannot eat baked goods like biscuits and cakes because they contain Trans_Fats, and nor can we eat fried foods (all restaurants re-use oils and many homes do too) because they contain HNE or even Acrylamides! The latter is a mysterious chemical which we still do not know enough about!
If oil must be re-used, here are some tips given by experts:
1. Strain the oil to get rid of the particles
2. Do not heat oil unnecessarily
3. Do not let the oil smoke. The important thing is to pick an oil with a high smoke point as once the oil crosses this point, it burns. Remember that the smoke point decreases with each use because of the particles in the oil, the presence of salt, exposure to oxygen, light, and heat.
4. Store the used and cleaned oil in the refrigerator or in any cool, dark place.
Signs of Deteriorated Oil:
Darkened Oil (this is because the oil and food molecules are burnt because of the heat).
Thick consistency. (This happens as the oil’s molecular structure changes due to the heat).
Particles suspended in the oil.
A rancid smell
Unfortunately Indians have increased their consumption of baked goods (a trend adopted from the west) – and at the same time continue to eat their fried favorites like potato wadas, samosas, cutlets, bhajias, chiwda mixtures etc. Also, we in India tend to eat late dinners (unlike in the west where eating around 7-8 p.m. is the norm) and therefore consume a lot of fried snacks in the evening. And then our meals often contain fried foods like paranthas, puris or bhajias.
This diet could well be contributing to the rapidly rising heart disease rates. According to a nine year old study conducted by President Kalam, the prevalence of coronary artery disease in India has increased from 1% in 1960 to 11% in 2001. It afflicts about 15% of the adult population today.
Eating healthy today means giving up baked goods and avoiding fried foods in restaurants and street corners.