[13 May] I have added a second recommendation for Macadamia Nut Oil
[8 May] I have refined my recommendation after further reviews of Walnut oil and do not recommend it for frying application.
When it comes to the selection of oils for cooking, it can be a tricky business. Before we begin, please take some time to think about the following:
1. What do you look out for in selecting cooking oil?
- Based on the “Healthier Choice” Logo?
- The price of the Oil?
- Using the same oil as a matter of habit?
2. Rank the following oil which you would use for frying:
- Corn Oil
- Grapeseed Oil
- Macadamia Nut Oil
- Sesame Oil
- Sunflower Oil
What is your first choice, and why?
Let’s look at some of the information we can pick out from a Vegetable Oil product label.
1. Healthier Choice labels:
- In Singapore, there are 2 “Healthier Choice” labels for cooking oil:
What does this tell us?
A “Healthier Choice” cooking oil logo informs us about the overall saturated fats and transfat content. Saturated fats and transfat, when consumed in excess, is believed to raise the bad cholesterol (LDL) and increase the risk of heart attacks/ strokes, as these fats deposit itself along blood artery walls and restrict blood flow. Transfat lowers the HDL (good cholesterol. “H” for Happy) as well.
The “No Transfat” label however, DOES NOT mean that there there is 0 transfat. It simply means that it is below statutory limit. Transfat occurs naturally in small amounts in some meat and diary, however, it is not found in vegetables. Industrial manufacturing process of vegetable oils can lead to the artificial formation of trans fatty acids. Recall the news about margarine spreads being tested positive for transfat.
What does the Healthier Choice label not tell us?
If we were looking at the balance between Omegas 6 and 3, the healthier choice label does not indicate any of that currently.
The importance of Omega 6 : Omega 3 Ratio
Studies show that the optimal Omega-6 to Omega-3 fatty acid proportion in our diet is in the ratio of 1:1, up to 4 (omega 6):1 (omega 3)
Let’s take a look at the Omega 6 : Omega 3 content of the common cooking Oils sold in our supermarket.
Note the below mislabel in Sunflower Oil. I contacted the Oil manufacturer but did not receive any response.
Why is a high Omega 6: Omega 3 ratio worrying?
The talk about Omega 6 is incomplete without making reference to Omega 3. Both Omega 6 and Omega 3 fatty acids play crucial regulatory roles in our body. As we would expect, an imbalance in the intake of one over the other will have a constant pro-inflammatory or constant pro-oxidative impact on the body. Either extreme is bad. Some inflammation is needed (for our bodily processes and to fight viruses) and anti-inflammation (to regulate against chronic conditions and long term diseases). However, our modern diets have shifted this balance to excessive omega 6 intakes, leading to our body to be in a pro-inflammatory state.
The most common sources of Omega 6 include consuming food cooked in Vegetable Oil that is very high in Omega 6, consuming animal meat or animal based produces such as milk, where the animal feed is high in Omega 6.
Studies show that a very high omega-6/omega-3 ratio promote the pathogenesis of diseases, including cardiovascular disease, cancer, and inflammatory and autoimmune diseases, whereas a lower omega-6/omega-3 ratio exert suppressive effects.
A Set of Statistical data:
In the secondary prevention of cardiovascular disease, a ratio of 4/1 was associated with a 70% decrease in total mortality. A ratio of 2.5/1 reduced rectal cell proliferation in patients with colorectal cancer, whereas a ratio of 4/1 with the same amount of omega-3 PUFA had no effect. The lower omega-6/omega-3 ratio in women with breast cancer was associated with decreased risk. A ratio of 2-3/1 suppressed inflammation in patients with rheumatoid arthritis, and a ratio of 5/1 had a beneficial effect on patients with asthma, whereas a ratio of 10/1 had adverse consequences.
Vegetable Oil content in Formula Based Milk
To mimic the high fat content of breast milk, Vegetable Oil is one of the major component that has been added to Formula Milk. Due to emerging links between inflammation and excessive Omega 6 intake, concerns arise with regards to the quantity and quality of vegetable oil being used in formula milk. Read more about the quantity of Vegetable oil in formula milk here.
For the above reasons, choose an Oil that has an Omega 6: Omega 3 ratio that is close to 4:1.
2. SMOKE POINT
Smoke point is the temperature above which oil becomes unstable and starts to breakdown (and as the name suggests, smokes). This temperature is important, because cooking with oil above their smoke point causes the oil to break down into components that speeds up aging, is cytotoxic, harmful or possibly carcinogenic.
Choose oils that have high smoke point to be safe for frying applications.
Note: When we do frying, temperatures can reach 170-190 degC.
3. MONOUNSATURATED OIL CONTENT
Monounsaturated Fats (Omega 9 fatty acids), which is predominant in Mediterranean diet, is thought to be good for the heart.
Hence, in the selection of oils, it is recommended to choose one with higher mono-saturated fat content.
Combining #1, #2 and #3, below is a list of the various smoke points of the different fats and oils we might come across on a daily basis. Some are actual store labels, whereas the rest come from research. Do bear in mind that these values are ball park figures; It really depends on the extent of processing, and the measurable extent in defining “smoke point”.
- SFA: Saturated Fatty Acid
- MUFA: Mono-unsaturated Fatty Acid
- Oils which are balanced in the Omega 6: Omega 3 are highlighted in yellow. Macadamia Nut Oil and
Walnut Oil (Semi refined)appear to be suitable for high temperature applications. **Note that unrefined Walnut oils have a low smoke point of 160degC and it is suitable for non heating applications.
- In consideration of the modern day diet which is excessively high in Omega 6, Perilla Seed Oil and Chia Seed Oil, could be used. Perilla Seed Oil is a common Oil used in Korean Cuisine, while Chia Seed Oil is good for non heating applications, such as in Salad Dressing.
- Canola Oil is not recommended for the following reason:
- Canola does not exist in the wild, and had been cultivated to reduce eurcic acid content to low enough levels for human consumption. These plants were subsequently Genetically Modified.
- About 80% of the Canola grown in Canada is now genetically modified to resist specific herbicides. We do not specifically know how a single gene modification impacts the entire plant. Without good knowledge, I would prefer something that is found in nature.
- Rapeseed Oil in the above table is the non-GM version of Canola Seed.
- Coconut Oil is not recommended due to its saturated fat content, and the ongoing research on the effects of Saturated fat on health.
- Fish Oil in the above table comes from a brand that is sold in the Supermarket. It has an imbalance in Omega 6: Omega 3 ratio, so do read labels before buying.
My after thoughts:
With respect to nutrition labeling for Cooking Oils, it is improving but still a long way to go. Smoke point is not currently indicated on nutrition labels, but it is a good information to have. Do buy Oils that shows their Omega 3/6/9 content so that we know what we are eating.
4. METHOD OF EXTRACTION
Vegetable/ Nut Cooking Oil is either extracted mechanistically, such as propeller pressed, or via chemical solvent extraction, e.g. Hexane/ heptane, which are petroleum based solvents.
Upon extraction, the oil could be directly packed and sold as it (Extra Virgin/ Virgin; Unrefined) is, or it undergoes further refinement to remove specific components in the oil that could perhaps breakdown more easily (Pure/ Light/ Extra light; Refined).
Generally, Extra Virgin Oils, having undergone only mechanical extraction, would be
more wholesome better in terms of its nutrients and flavor, antioxidants, enzymes, co-enzymes as compared to its refined counterparts. The main difference between the different processing methods lie in the nutrition level, taste and smoke point. The more refinement, the lighter the taste of the oil, less nutrition, higher smoke points and higher chance of having remnants of the solvent used for processing.
5. METHOD OF STORAGE
Oils from the supermarket is often stored in glass bottles or plastic container. Due to ongoing concerns with migration of plastic molecules to oil (research ongoing), I would opt for glass storage containers as glass is more inert. (Bearing in mind that the raw materials for making plastics is Crude Oil, the same raw material that gives us our petrol).
(Paul Pitchford, “Healing with Whole Foods: Asian Traditions and Modern Nutrition”, North Atlantic Books; 3rd edition (2002), pp 186-187).
Where it is possible, I would opt for tinted glass bottles to minimize natural oxidation of vegetable oils from the sunlight. Another way is to store the oils in a cool and dark place.
In choosing for a “Healthier” Cooking Oil, look out for these factors, in order of importance:
1. Omega 6: Omega 3 ratio
Keep the ratio as close to 1:1 to 4:1 as possible
2. Smoke Point
Choose oils with appropriate smoke point for different purpose, e.g. High smoke point of above 190 degC when frying food.
3. Monosaturated Fatty Acid Content
Choose oil with higher Monounsaturated Fatty Acid as opposed to Polyunsaturated Fatty Acid.
4. Method of extraction
In tandem with the Omega ratios and smoke point, choose Oil that has been mechanically extracted for best nutrition and lowest in chemical solvent remnants. Buy Oil that is cold pressed and unrefined to obtain maximum nutrients and eliminate residue (e.g. Hexane) remnants.
Buy oil that is packaged in glass bottles and store them in cool and dark conditions, away from sunlight to preserve best nutrition in the oil and minimize oxidation. Remember to recycle the bottle to save our precious resource!
Below is my Recommendation for cooking oil.
- Macadamia Nut Oil [Added 13 May]
- Macadamia/ Perilla Nut Oil blend.
- A blend consisting of 95.5% macadamia oil and 4.5% Perilla seed oil. The Omega 6: Omega 3 ratio is 1:1. It has a mild nutty taste and it is suitable for frying due to its higher smoke points.
Note: I have seen certain Macadamia Nut Oil that tested zero for Omega 3. I am not sure why, but please do take note and only buy Oils that shows a good balance between the Omegas. Adding Perilla Oil has an advantage of stabilizing the omega ratios as Macademia Nut Oil ratios tend to vary when used on its own.
Food for thought
If you have additional moments, please read on for some interesting food for thought:
1. Vegetable Oil trend and cancer trends
The chart below shows the proliferation of modern day diseases along the prevalence of vegetable oil into our diet. Of course, correlation does not necessarily imply causation, however, it is worthwhile to investigate further.
(Anti-Cancer, A New Way of Life. 2011. pp 100/ 103. Dr. David Servan-Schreiber)
2. If Vegetable oils are bad, why is Vegetable good? Aren’t they of the same origin?
The extraction of a nutrient from its original source could transform that nutrient’s biochemical structure. In whole food form, nutrients exist collectively. The protective ability of food against free radicals does not only stem from a single phytochemical (nutrients only found in plants), but it is a synergistic interaction between the collective nutrients of the whole plant.
Though vegetables are good for us, their molecular structure undergo changes and many of the nutrients can get destroyed during processing, especially chemical extraction. Hence, when consuming oil, we should choose one with the fewest disadvantages.
Any type of cooking oil is bad for us when consumed in huge amounts. Instead, choose food that is naturally high in fats, for it would have its other wholesome nutrients.
The same applies for vitamins and mineral supplements. In the case of vitamin C, when it is isolated via extraction or lab synthesized, it is more likely to oxidize and lose it’s protective functions as opposed to when it is in the orange. Scientists postulate that it is the powerful phytochemicals liked-limonene in the orange that is beneficial to the health of the immune system.
Just as a car is useful to transport us from point A to point B and the core mechanism of the car is its powerful engine, this engine is of limited use without the other car components e.g. steering wheel, car seats, etc.
3. Never reuse Oil
Have you noticed that in retail cooked food establishments, Oil gets used for a long time? Especially for deep dried food, where the quantity of Oil is huge.
Toxic components can be generated with prolonged/ reused Oil. One example is Malondialdehyde. Malondialdehyde is present in oils in small amounts and increases 10 times or more when oil is reused.
Oil that is used for prolonged periods, especially vegetable oils, will result in the breakdown of polyunsaturated fatty acids. With prolonged use, the smoke point of the oils will be lowered, and this results in a viscous cycle where more fatty acids gets oxidized, and more harmful compounds are formed. These components are toxic and can be carcinogenic.
For this very simple reason, I generally avoid deep fried food retailed outside.
Health is wealth. Maintain a good balance.
I do hope that the above has been useful for you.
Do let me know should you have recommendations or comments.
Cheers to a larger life!