Cold-pressed oils: Benefits and side effects

Seed oils are extracted through two methods. The more popularly used method involves the extraction of oil using a chemical solvent, which is then refined or chemically altered to remove impurities and add nutrients (to make “fortified oil”).

Cold-pressed oils, on the other hand, involve crushing the seeds in a mechanical press to separate the pulp from the oils. While cold-pressed oils may have some impurities (which is essentially some of the pulp) they do not require high heat or chemicals during their extraction, which is the primary reason why they are considered to be beneficial.

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There is now growing evidence that cold-pressed oils have many health benefits to impart. The following are some benefits you are likely to get by including cold-pressed oils into your diet. 

• Immune boost: As mentioned before, cold-pressed oils are packed with nutrients and especially antioxidants. Getting more of these nutrients can not only give your immune system a boost but may also prevent your body from free radical damage.
• Heart healthy: While you may be suspicious of oils being cholesterol heavy and harmful, cold-pressed oils are actually rich in polyunsaturated fatty acids (PUFAs) which are considered to be heart healthy. Cold-pressed oils also contain omega-3 and omega-6 fatty acids, which are also great for your heart. (Read more: Heart disease)
• Blood sugar control: Some studies suggest that consuming cold-pressed oils like virgin and extra virgin olive oil can keep your blood sugar levels under control and may even reduce the risk of type 2 diabetes. Cold-pressed oils are also believed to help lower your blood sugar levels after a meal, which is vital for diabetics.
• Fights inflammation: Because they are packed with antioxidants and healthy fats, studies show that cold-pressed oils can help reduce inflammation levels. It’s important to remember that cold-pressed oils are chemical-free plant-based options and so they have anti-inflammatory properties that you can benefit from.
• Great for your skin: Cold-pressed oils are stable, packed with antioxidants and completely chemical-free. This makes these oils perfect for your skin and scalp as their application not only moisturizes but also prevents allergic reactions, acne or rashes.

Different cold-pressed oils have different levels of PUFAs and antioxidant compositions depending on their source seed or nut. Most cold-pressed oils available in the market are packed with PUFAs and antioxidants which often results in autoxidation. This lipid oxidation process deteriorates the oil quality by the accumulation of unhealthy sediments and causes its shelf life to be short.

(Read more: Nuts and seeds)

To counter this issue, many cold-pressed oil companies tend to fortify these oils or modify the oil manufacturing technology to increase their shelf life. A common practice is to add some amounts of unsaturated fatty acid oil or refined oil to cold-pressed oils, which diminishes the nutritional value of the original product. The trans fatty acid content of these adulterated oils increase and consuming these oils can’t benefit your health as much as consuming pure cold-pressed oil could. 

Another method is the addition of steam treatment during the manufacturing process. This method introduces heat to the manufacturing process, which - although having a stabilising effect on the oil - renders it as an equal of refined oils and negates the benefits of the cold-pressing process. While food standard authorities have strict guidelines for the stabilisation of cold-pressed oils through these processes, it’s best to check for the mark of these authorities while you’re purchasing cold-pressed oils.

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A study published in the International Journal of Molecular Sciences in 2018 explains that cold-pressed oils have better nutritive properties since they have not been refined. Since cold-pressing does not involve heat or chemical treatments, the components and therapeutic effects of cold-pressed oils remained much higher than other oils. 

Cold-pressed oils also contain a very high concentration of antioxidants and phytonutrients like tocopherols, sterols, stanols, phospholipids and phenolic compounds. Most cold-pressed oils are also rich in polyunsaturated fatty acids (PUFAs) which are also good for your health. These oils are also known as fixed or stable oils because they are not volatile at room temperature. However, the presence of antioxidants often makes cold-pressed oils prone to autoxidation, which leads to low shelf life and deterioration unless preserved properly. 

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Cold-pressed oils are generally considered to be healthier than refined oil primarily because of their method of manufacturing. Heat and additives are not added to the cold-pressed oil manufacturing process, which allows them to retain more bioactive compounds like vitamins, minerals and antioxidants. This makes consuming cold-pressed oils a healthier choice.

However, checking the labels of cold-pressed oils in the market is very important. This is because cold-pressed oils may have a short shelf life and you’ll have to use them up within a prescribed duration of time. Buying in bulk is therefore another thing that cannot be done with cold-pressed oils. Further, check the label to see if any refined oils or steam has been introduced during the manufacturing process. If these modifications have been made then it’s best to choose another oil as these processes reduce the benefits of cold-pressed oils.