Can It Be Used for Cooking?
What is flaxseed oil?
Flaxseed oil, also known as flax oil or linseed oil is made from ripened flaxseeds (Linum usitatissimum) that have been grounded and pressed to release their natural oil. Man had used flaxseed oil for thousands of years as it offers a wide range of health benefits. It is a rich source of the essential omega-3 fatty acid. Although flaxseed oil is healthy, it does not contain the same nutrients as the whole seed. For example, whole flaxseeds contain fibre, magnesium, vitamin B and anticancer lignans but its oil does not.
Types of flaxseed oil
Most of the flaxseed oils available in the market are cold-pressed. In general, they can be divided into 3 basic types:
Lignans are known to provide important health benefits. Some of the lignans found in whole flaxseeds can be converted into mammalian lignans, known as enterolactone (ENL) and enterodiol (END) by bacteria in the colon. They can reduce the risk of various cancers such as breast cancer in women and prostate cancer in men.
How is flaxseed oil made?
Cold-pressed flaxseed oil is a very light and delicate oil with a slight nuttiness when fresh. Cold pressing is usually carried out at temperature less than 60oC and the resulting cold-pressed oil retains almost all of the nutrients in the flaxseed. It is rich in polyunsaturated fatty acids, tastes fresh and not greasy. Cold pressing involves the following steps:
Harvest and screen flaxseeds, then filter to remove any impurities.
Ground the seeds into a paste.
Apply pressure to the semi-solid paste to force the oil out.
Filter the pressed oil through a series of filters.
Carry out a decantation process to separate the remaining sediment from the oil by the simple force of gravity.
Although cold pressing results in a 100% pure and natural oil that retains all its properties, the disadvantages are low yield efficiency and relatively high cost, compared to hot pressing and solvent extraction. Nonetheless, the high temperature seed frying in hot pressing process would lead to protein denaturation and reduce the content of effective composition in the oil. Similarly, in solvent extraction method, almost all nutrients are destroyed with trace amounts of residual organic solvents.
Cold-pressed flaxseed oil is a rich source of omega-3s as shown in the breakdown below.
Fatty Acid Breakdown:
Omega-3: Omega-6 ratio = 3 : 1
Made from ground and pressed flaxseeds, flaxseed oil provides numerous health benefits:
- High in omega-3 fatty acids
Flaxseed oil is very high in omega-3s. One tablespoon (15ml) of flaxseed oil provides 7,196mg of omega-3s. This promises a wide range of potential benefits, including healthy inflammatory response1, healthy heart2 and protection against brain ageing3. If you don’t eat 1 – 2 servings of fatty fish each week or you are not taking any fish oil, supplementing your diet with flaxseed oil will be a good alternative to fill the nutritional gap.
Support healthy blood pressure
A study shows that dietary supplementation with one tablespoon (15ml) of flaxseed oil for middle-aged men with high blood lipid profile for 12 weeks led to significant lower blood pressure, compared to those supplemented with safflower oil4. This result suggests the heart protecting effects of flaxseed oil, which could be attributed to the omega-3s.
Support skin health
A study shows that women whose diet were supplemented with flaxseed oil for 12 weeks experienced smoother skin and better hydration, and skin sensitivity to irritation, skin roughness and scaling significantly decreased5. Animal test showed that mice with dermatitis (skin irritation) administered with flaxseed oil for 3 weeks had decreased redness, swelling and itch6.
- May help reduce cancer cell growth
Several animal studies show that flaxseed oil helps reduce the growth of cancer cells. In one study, mice which were administered with flaxseed oil for 40 days were found to have their cancer and lung tumours7 growth suppressed from spreading. Besides, it has also been shown to prevent the formation of colon cancer in rats8. Although the results are promising, more research is needed to determine how these results can be translated to benefit humans beings.
May help treat constipation and diarrhoea
In a study, constipated patients on hemodialysis were supplemented with flaxseed oil, results showed an increased frequency of bowel movements and improved stool consistency9. Besides constipation, it is also effective as an antidiarrheal agent10. Although the results are encouraging, further research is required to determine its efficacy in the general population.
- Short shelf life
Although flaxseed oils are good for you at the point at which they come off the presses, a major problem with cold-pressed flaxseed oil is its short shelf life. Without refining and processing, these oils turn rancid easily and quickly develop a bitter taste and rancid smell. Flaxseed oil should always be bottled in a dark-coloured bottle, as the oil is heat and light-sensitive. It is best to store in a cool and dark spot such as the refrigerator. It can be kept for 2 months in the refrigerator and for 3 to 4 months in the freezer.
- Unsuitable for cooking
Cold-pressed flaxseed oil is not intended to be used as a cooking oil due to its low smoke point of 107°C (224°F). Since it does not tolerate heat well, it will oxidise easily and become harmful to health when exposed to heat. It is best to use flaxseed oil for salad dressings or as a seasoning for foods to boost richness and nutritional content, especially omega-3s. It can also be added to soups before serving to increase richness.