In such matters, it is best to listen to the experts. Doctors, Nutritionists and Dieticians point out that an ideal cooking oil should have the following characteristics:
It should be cholesterol-free
It should be trans-fats-free
It should be low in Saturated Fats
It should have high levels of MUFA and PUFA
It should have an ideal Omega-6 to Omega-3 ratio
It should have a high smoking point
It should be natural and free from chemicals
Mustard Oil controls bad cholesterol (LDL) and boosts good cholesterol (HDL); it contains zero trans-fats; it has the lowest levels of Saturated Fats among all cooking oils; it is rich in good fats, namely Monounsaturated Fatty Acids (MUFA), Polyunsaturated Fatty Acids (PUFA) and Omega-3 Fatty Acids; it has an Omega-6 to Omega-3 ratio that comes closest to the ratio recommended by the World Health Organisation; it has a high smoking point which makes it ideal for Indian cooking; and it is completely natural and contains no chemicals or artificial additives.
So there is no reason to be confused about which cooking oil to choose. The parameters are well-defined… and the choice is clear.