The modern day supermarkets offer a wide variety of edible oils ranging from olive to rice bran. There are heart friendly oils which promise you a healthy heart in their advertisements. And finally there are different brands of the latest craze, olive oil. Its very difficult for an average consumer to make this choice. However this choice is very important as it has major implications on health. In this article we will guide you through some parameters basis which you could navigate this maze. We shall use four criteria to make this choice:
1. Process of Extraction
2. Composition of fat types in an oil
3. Quality of the seed
4. Essential Fatty Acid Profile
5. Type of cooking
6. Season of the Year and geography
The Process of Extraction: Refined vs Cold Pressed
This by and large is the most important parameter in this choice. Most oils that are sold in supermarkets are refined oils. The process of refining involves various stages like extraction, degumming, neutralisation, bleaching and deodorisation, finally resulting in a product which is colourless, odourless, tasteless and can literally last on the grocery shelf for eternity. Lets look at each of these processes.
Extraction involves crushing and steaming the seeds. But to make this more efficient, solvents like hexane ( a petroleum product) are used. There are often residues in the oil and cake. And the cake makes way into our food as its used as animal feed. Sometimes its more direct through products like soya meal maker.
The next process is degumming where phosphatides are removed by adding water.
Neutralisation involves removal of free fatty acids that reduce the shelf life. However free fatty acids by themselves could be useful for health. This is done by adding phosphoric acid.
Bleaching is done to remove any colour pigments like chlorophyll and other antioxidants. This process strips the health benefits of antioxidants.
Finally deodorisation is done to remove any odours which give different oils their unique character. This step involves very high temperatures and could also result in formation of harmful transfats.
Cold pressed oils on the other hand are extracted in a traditional wood press without heat. This retains all the vitamins like tocopherols and the unique flavour of the oil. It also retains the natural antioxidants which are protective.
Bottomline: Always prefer cold pressed oils over refined oils
Quality of the seed
The quality of the oil is only as good as the quality of the nut or seed from which it is extracted. While this might sound obvious, the devil lies in the detail. The nutrient profile of the seed/nut is a function of the soil fertility. Chemically grown produce have a very weak nutrient profile as the yield is driven by chemical fertilisers. For example the iron content of apple has gone down by 60 % in the last few decades, however we eat apple and think its giving us a lot of iron. The same applies to chemically grown oil seeds. The micronutrient profile of the same would be lesser than seeds grown without any fertilisers in natural farming methods.
Bottomline : If you can afford it, make sure you buy oil extracted from naturally grown oil seeds or nuts.
Type of Fats : Saturated vs Monounsaturated vs Polyunsaturated Fatty Acids
Saturated Fats have no double bonds in their structure and most commonly found in animal fats. These fats have been demonised for quite some time, thanks to the Diet Heart Hypothesis by Ancel Keys and the fear of cholesterol. However recent evidence has proved it to be beneficial and thus our good old ghee has made a comeback. In fact 60% of human brain is made of saturated fats and these play a key role hormonal balance of the body.
Monounsaturated fatty acids (MUFA) have a single double bond and are known for their health benefits. Olive oil owes it health benefits to the presence of MUFA. Groundnut oil also has a considerable amount of MUFA.
Polyunsaturated Fatty Acids are mostly found in vegetable/seed oils and have two double bonds. These oils are easily susceptible to oxidation especially when refined.
Bottomline: Saturated fats and mono unsaturated fats are the best. Polyunsaturated fatty acids are better consumed in minimal quantities.
Essential Fatty Acid (EFA) Profile : Omega 6 vs Omega 3 ratio
Essential Fatty Acids are those fats that the body can not synthesise and needs to supplemented through diet. There are mainly two types of EFA’s. Omega 3 and Omega 6. While both of these are essential there is a catch. We need the right balance of these for healthy bodily functions. Both these help in synthesis of prostaglandins that form hormones. However if the ratio of omega 6 is higher, it produces inflammatory prostaglandins and a consistent production of these could result in disease.
Oils like sunflower, safflower, sesame are very high in omega 6 and are better avoided if you have inflammatory conditions like allergies, heart problems etc. Mustard oil is a good example of the right balance. It is also worth noting that within mustard oil the ratio is much better in cold pressed oil. Even groundnut oil has a good balance.
Bottomline : Minimise the use of oils rich in Omega 6 like seed oils and seek oils with a balance like mustard, groundnut.
Type of Cooking
This also plays a major role in the selection. Olive oil inspite of all the benefits, is not very suitable for deep frying and should ideally be used for dressing and saute.
Groundnut oil is very good for deep frying as it has a high smoke point.
Ghee is good for preparations that involve repeated frying like sweets. The reason why all old sweet houses had a tag line of “Pure Ghee Sweets”
Bottomline : Use ghee for sweets and groundnut or mustard for deep frying.
Season of the Year and Geography
Some oils are better for us in certain times of the year. Sesame oil is highly recommended for winters as its very good for joint health and skin. Also sesame and mustard oil generate heat which is needed in the body in winter. Mustard oil is also known to reduce phlegm.
Groundnut oil is good for summer season.
Ghee is good for most part of the year but is good for winter in particular. No wonder Diwali and Dussera fall in this season.
It is strongly advised to consume oils that are native to your area. Coconut oil could work wonders along sea coast. Mustard oil is preferred in the north and groundnut in Gujarat. These aspects of local biodiversity have to be respected.
Bottomline : Eat local and Seasonal
Finally a note on the pricing. Cold pressed oils are much more expensive than refined oils as it takes around 3 kg of groundnut to extract 1 litre of oil in cold press whereas in refined process it takes just 1.8kg. Further cold press is a labour intensive process. However it does make up for the cost in terms of health benefits. If you can afford cold pressed and also naturally grown seeds, thats the best money can afford and of course its expensive. But the right question is not why is cold press expensive but ” WHY IS REFINED SO CHEAP?”