Professor of Cardiology, AIIMS, New Delhi
With the multitude of possibilities and even more allegations and counterclaims by the edible oil manufacturers, patients and laypeople alike are often at a loss as to which oil is heart-healthy and ideal for daily cooking needs. In case of doubt, who should you turn to besides the attending physician in particular or the good old doctor in general? However, most doctors cannot answer this simple question. Very often they give unconvincing answers or, at best, refer the patient to a nutritionist, which leaves the patient quite dissatisfied. The ambivalence of medical professionals in this context is due to the huge commercial and technical jargon in this area: MUFA / PUFA, trans fat, smoke point, rancidity, N3: N6 ratio, etc. This opinion article is an attempt to address some of these problems.
Origin of the controversy
All of this confusion started with lifestyle changes and the heralding of new age technology. The hydrogenation of vegetable oil to Vanaspati Ghee was a food revolution; it led to the development of oil that resembled Desighee (which has always been the preferred oil in India) but had enormous storage capacity from a commercial point of view. What really made the deal special, however, was that it was also very cheap. But history agrees that widespread use of this oil coincided with a sudden coronary artery disease (CHD) epidemic. At this point it was recognized that oils rich in saturated fat (SFA) could be harmful to health, at least in connection with heart disease. This led to another massive shift in cooking practice, with consumers switching from Vanaspati ghee to oils that were low in SFA, such as sunflower oil or safflower oil, practically overnight.
Later research found that these oils themselves (although they contained very little SFA) weren’t very healthy either, perhaps because they were imbalanced (they were high in polyunsaturated fats (PUFA) to the exclusion of all other types as well as unhealthy N3: N6 At this point it was recognized that an oil rich in monounsaturated fats (MUFA) or at least balanced (SFA: PUFA: MUFA = 1: 1: 1) might be the ideal choice, which led to another shift the cooking practice of Nun, western oils with a supposedly high MUFA content (extra-virgin olive oil or canola) were used, at least by those who could afford it.
However, it was later discovered that these oils had a very low smoke point (the point where any oil began to smoke and denature as soon as the temperature was raised) and therefore may not be suitable for Indian cuisine where cooked over high heat will and fry. At high temperatures, these “Western Oils” can break down / denature into toxic end products that can be even more harmful than any other oil. There is currently some evidence that SFA alone (when used in moderation) may not be that bad, but that trans fatty acid (TFA) is the worst culprit. Apart from fatty acids, other components of the oil such as antioxidants can also be protective factors.
FIGHTING THE JARGON
TYPES OF FATTY ACIDS
Saturated fatty acids: The fatty acids in oils appear in the form of carbon chains that are linked together either by a single “carbon bond” or sometimes by one or more double bonds. If it is linked by a double bond, there is a possibility of taking in an extra hydrogen ion and thus this oil is unsaturated. On the other hand, when all of the double bonds are broken and only single bonds remain between the carbon atoms, there is no more room to add hydrogen ions and it is known as “saturated” fat. When there is only one double bond, the fat is known as simply saturated fat (MUFA). However, if there is more than one double bond it is called a polyunsaturated fat (PUFA). Saturated fats are generally solid at room temperature, while unsaturated fats are liquid. Health-balanced oils (MUFA / PUFA / SFA; 1: 1: 1) or oils with a high MUFA content are considered to be the best, such as mixed oils or mustard oil, olive oil or rice bran oil. These are better than predominantly PUFA oils; Sunflower oil or safflower oil, which in turn are better than oils rich in SFA such as desighee, butter, coconut oil or palm oil. The worst oils, however, are some unsaturated oils which, during the process of reuse or hydrogenation, twist some carbon chains on the double bonds and become trans fatty acids (TFA). Vanaspati Ghee, or any reused oil, is a good example of this type. The predominant FS types of some oils commonly used in Indian cooking are listed in the table.
OMEGA 6 AND OMEGA 3
Both are types of PUFA; in omega-3 fatty acids the first double bond is on the 3rd carbon atom (counting from the methyl end of the chain), while in omega-6FA it is on the 6th carbon atom. There is some evidence that oils that are mostly rich in omega-6FAs may be worse off than even SFA. The Sydney heart study found that replacing SFA with linoleic acid (an omega-6 fatty acid) could increase the risk of death in patients with CHD. Sunflower, safflower, and corn oils are also rich sources of omega-6. On the other hand, oils high in omega-3 FAs such as fish oils can prevent heart attacks.
As soon as oil is heated the temperature rises and at a certain point it begins to generate smoke known as the “smoke point”. Chemically at this point, the triglycerides are first broken down into fatty acids and glycerin, and then the glycerin is further broken down, producing more fumes and unhealthy free radicals. Thus, the health benefits of any oil are lost once it reaches the smoke point. The Indian way of preparation involves high heat, especially when deep-frying, and therefore only oils with a high smoke point can be used. Extra virgin / virgin olive oil and butter with a low smoke point is therefore completely unsuitable for Indian cuisine and could even be harmful. The smoke point of some common oils used in Indian cuisine are given in the table.
INDIAN COOKING TIPS AND TRICKS
1. The reuse of oils is extremely harmful. It involves the conversion of unsaturated FA to TFA, which is the most harmful fatty acid.
2. Blended oils or blends of 2-3 oils are good choices with at least one oil that is rich in MUFA.
3. If single oil is to be chosen, MUFA-rich oils are good. Rice bran oil, mustard oil, peanut oil are good options
4. Hydrogenated oils or Vanaspati ghee are the worst oils as they are high in TFA. So dishes cooked in Vanaspati Ghee; Street food, dhaba food, bhujiyas, cookies, etc. should be avoided.
5. Natural (unprocessed oils) are better than processed oils.
6. Dietary cholesterol intake is no longer of great concern. Hence, eating eggs is not harmful.
7. Low smoke point olive oil is not ideal for Indian bhunoing (deep-frying) cooking, but can be used as a topping on salads.
For healthy Indian cooking oils rich in MUFA and those with a high smoke point should be used: Rice bran oil, mustard oil, or ground oil are good options. Another clever option is to use 2-3 oils separately or mixed together. Trans fats are the main culprit and therefore reuse of oils and vanaspati ghee should be avoided at all costs.
Table properties of some oils used in Indian cuisine
oil Predominant fatty acids Smoke point area
butter BAR <200? C
Vanaspati Ghee TFA <200? C
Extra virgin olive oil / virgin olive oil Jack <200? C
Rapeseed Jack 200-229? C
Sunflower oil PUFA 200-229? C
peanut oil Jack 230-250 ° C
Corn oil PUFA 230-250 ° C
Coconut oil BAR 230-250 ° C
Palm oil BAR 230-250 ° C
Soybean oil PUFA 230-250 ° C
Pomace oil Jack 230-250 ° C
Ghee BAR > 250? C
Mustard oil Jack > 250? C
Rice bran oil Jack > 250? C
Safflower oil PUFA > 250? C