Flax (linseed) oil and is it safe to cook with it?

People often say “I thought you shouldn’t cook with linseed(flaxseed) oil?”

THE SHORT ANSWER

Careful safe cooking of omega-3 foods

Well there is cooking and cooking. Just as everyone cooks their omega-3-rich oily fish; effectively the wetness of the fish keeps the cooking temperature in the safe zone for omega-3. Drizzling linseed oil over a baked potato or streamed veg is similarly fine; and even recommended by Nobel-prize nominated scientist Dr Johanna Budwig. Flax Farm uses the same principle to bake Flaxjacks at safe low temperature.

Vegetable oils should not be cooked  at high temperature

Scientific studies have shown Flaxseed/Linseed oil is heat stable at 150C for at least 1 hour without degrading but temperatures over 170C cause omega-3 to degrade. Cooking by frying, stir-fries and roasting can result in fat reaching very higher temperatures that can be over to 300C which is most detrimental to omega-3.  These very high temperatures are bad for polyunsaturated vegetable oils, further details laid out below. For many people cooking with oil simply means frying or roasting; in order to discourage people from damaging the precious linseed oil at these high cooking temperatures blanket advice is given not to cook with linseed  oil.

Flaxjacks are gently cooked

Flax Farm is very careful about all its production from cold-pressing the linseed (or flaxseed) oil, cold-milling ground linseed and making Flaxjacks®.  Flax Farm Flaxjacks are baked  at in a low temperature oven below 150c but because water is added to  the cake mixture the cooking temperature is not much over 100C. This means the temperature of a baking flaxjacks is similar to that of the inside a baked potato when you cut it open.  When linseed is used in baking it is also protected by its own natural antioxidants which includes lignans.  http://flaxcouncil.ca/resources/nutrition/technical-nutrition-information/flax-a-health-and-nutrition-primer/   and http://www.whfoods.com/genpage.php?tname=foodspice&dbid=81

Flax Farm recommends you do not use Flax Farm cold-pressed linseed (flaxseed) oil to fry or roast

Flax Farm does not recommend barbequing, grilling, frying or roasting with linseed oil as that can result in excessively high temperatures. In addition, at Flax Farm we do not recommend frying with any unsaturated vegetable oil, at high temperatures, that includes corn oil, rapeseed and olive  oil.

THE LONG ANSWER

At Flax Farm we take great care to make healthy great tasting food

Whole and ground flaxseed have been a favourite ingredient in baking for centuries.  Flaxseed is a food with very unusual natural chemistry – which is what makes it so good for you!  Some of the chemistry of flax has caused confusion giving rise to a bit of mythology about the food and whilst it is more sensitive than other oils it is a lot more robust than people give it credit for. We cold-press the oil and cold-mill the seed to maintain its nutrients. Baking flaxjacks is done very moist at low temperature and the Flaxjacks themselves remain below 100C .

What’s the difference between Fat and Oil

Before we get going on this answer I will quickly clarify this nomenclature. The terms “fat” and “oil” have no difference scientifically when referring to food.  The two terms are more or less interchangeable but fats is a word that covers all fats and oil but “oil” is simply a colloquial term for fat which is locally liquid at room temperature. Coconut “oil” is so called because where it grows is much hotter and it is usually liquid though where it grows and is processed but here in the colder UK due to being mainly saturated fat, it becomes a solid “fat”.  Olive oil, which typically contains more than 50% more saturated fat than flaxseed/linseed oil often white and sludgy, almost completely solid if stored in a cold room or the fridge  but flaxseed oil will remain liquid.

Omega-3: should linseed oil be cooked?

My next issue was should linseed oil with its omega-3 and can it be cooked with safely.  The first thing I researched was eating oily fish – the most famous source of omega-3. With very few exceptions this is cooked before being eaten. The use of oily fish seems all positive and no negatives due to cooking fish with its omega-3 oils.

Research has been done into the stability of flaxseed oil with heat. The study I read was that it is heat stable at 150C for 1 hour without degradation.

Cooking Omega-3: Flax muffins proves health benefits

When we got into the scientific papers invariably scientists researching the health benefits of flax cook it into muffins and commonly have their guinea-pigs enjoying up to 50g of flax per day.  The scientists were able to compare the results of those who had eaten flax muffins to those who hadn’t eaten flax, so obviously the scientists found cooking didn’t remove the benefits of flax(linseed).

We started using ground linseed in Flaxjacks and people who worked here and only ate their flax in the Flaxjacks – just because they liked them – reported with surprise typical omega-3  related health improvements such as reduced aches and pains from arthritis and bad backs.

Confusion and misinformation

People are quite rightly concerned about heat and cold-pressed linseed (flaxseed) oil but there is also a lot of confusion and misinformation out there.

Generally we and almost everyone else glibly tells people “Don’t cook with linseed (flaxseed) oil”.  This is because most people who make or promote linseed oil are very health conscious and respect the less stable nature of omega-3 fatty acids.  However most of the reason that this dire warning is given is because to many people cooking with oil simply means frying.  The warning is a good one because it makes sure that these highly unsaturated oils are not overheated.

Saturated more stable than unsaturated fat

All unsaturated vegetable oils are relatively unstable compared with saturated fats are much more stable and less inclined to react with itself or other foods. This is why many people recommend frying with coconut oil or beef dripping. It is less prone to chemical changes during cooking.

Different sorts of vegetable oils

All vegetable oils are a combination of fatty acids, Fatty acids are chain-like building-blocks or strings of atoms that make up fats. Saturated fat or oils Unsaturated oils include monounsaturated, such as olive oil and polyunsaturated such as sunflower, safflower and linseed (flaxseed) oil. These oils are all similar in some ways, the chain length being the same in the main but as the more unsaturated a fat is the less stable it is.

Cooking and Frying with flax

Just as one can safely cook oily fish by baking, frying or grilling it is safe to cook and even fry with cold-pressed linseed oil cooked so long as you are careful   http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4375225/ :   “In China, stir frying of flaxseed oil at 150 °C is very common for cooking purposes (Pan 1990). Some studies state that stir frying of flaxseed oil upto177°C did not cause any loss to the quality of the oil (Hadley 1996)”

Frying can involve incredibly high temperatures in excess of 300C which is designed to create typical flavours of fried food through complex chemical reactions.  To quote www.seriouseats.com (http://www.seriouseats.com/2012/06/the-food-lab-for-the-best-stir-fry-fire-up-the-grill.html): “Perfect stir-fries should have a complex smoky, singed flavor known as “wok hei” – the breath of the wok. It comes from a combination of polymers and oil breaking down within the skillet”; this is serious chemistry territory and probably too hot for healthy food

Maillard Reaction, and free radicals

Western cooking traditionally uses a very hot frying pan or deep fat fryer and heavier weight of ingredients which are heated for longer and the food is browned,  This is a combination of carmelisation and something called the Maillard reaction where amino acids and (reducing) sugars such as those,  in steaks, fried onions and fried bread react, brown and combine in hundreds of different ways which also produce free radicals.  This chemistry has a knock on effect in attacking the oil in the frying pan and encouraging oil molecules to react with the browning food and other molecules within the oil itself. The oil then oxidises, polymerises and undergoes other chemical changes including cyclization  causing both the chemical and physical nature of the oil in the frying pan to change.

High Temperature frying

During heating, such as frying, vegetable oils containing linoleic and linolenic fatty acids  at temperatures above 200C monomeric cyclic fatty acids are formed.  This is part of the reason why oil that has been used a few times in a deep fat fryer becomes thicker and sludgy.   http://lipidlibrary.aocs.org/OilsFats/content.cfm?ItemNumber=39196  The toxicity of these new cyclic fatty acids has not been much researched but have been shown to cause inulinapenia and may cause other metabolic issues.

Confusion over bitter taste and rancidity in flax

Part of the problem with linseed which causes people to worry that it is rancid is in fact due to compounds called cyclolinopeptides which degrade and cause the oil to become very bitter. These compounds seem to have synergistic health benefits; research is beginning to uncover these benefits to the immune system which may well be contributory to why the Holism study discovered flax (linseed) oil to be more effective than fish oil. This bitterness seems to be worse in seed that has not been grown, harvested or stored correctly, it occurs within days or weeks of pressing, cooler temperatures slow its progress down albeit only  a very little.  This bitterness is often mistaken for rancidity and is behind  a lot of the worry about using flax in food; the taste of oxidised rancid oil is different and seldom spotted by the average person when consuming oils such as olive oil, sesame oil, walnut oil or rapeseed oil.  Not cooking with flaxseed oil to prevent bitterness is shutting the door after the horse has bolted, cooking doesn’t cause it but can make it appear worse when warm.  This bitterness is exceedingly common in flaxseed oil.  It has nothing to do with omega-3 chemistry or rancidity. Much of the world’s flaxseed oil has this bitter flavour, especially that sold in clear bottles. The degradation of these chemicals is brought about rapidly by uvlight, temperature has a far slower effect.

Flax Farm flaxseed oil and ground linseed (flax) is not “stored” but cold-pressed/cold-milled by us just before dispatch or use in our kitchen.

The Flax Council of Canada has a primer, http://flaxcouncil.ca/resources/nutrition/technical-nutrition-information/flax-a-health-and-nutrition-primer/ with lots of information about using flaxseed/linseed for health, its production, processing and storage. Correctly handled it is stable for far longer than we at Flax Farm  recommend – we are just being more careful.  There is reference there for storage and stability of ground flax, it is more stable than I had expected, and they recommend longer storage of the product than ever Flax Farm practices.  The original reference to “not storing ground linseed” was Dr Johanna Budwig. As Budwig was working on a diet for cancer patients in Germany after WW2 where food adulteration was rife I am sure she told people they had to use freshly ground linseed to protect them from adulterated foods because a ready ground product then  could have contained anything, including chemically extracted contaminated linseed meal.   Dr Budwig herself created a breakfast cereal made with ground linseed called Linomel made up, boxed and sold on the shelf with a longish shelf life. Dr Budwig also recommended against frying with linseed/flaxseed oil however she did suggest frying with linseed oil-coconut oil mix called oleolux for us to “three minutes”.   She also recommended using this oil on dishes  (hot) cooked buckwheat and baked potatoes. She was a very highly qualified chemist and a senior chemist for fats in Germany. Her reputation and efficacy of her diet still stands.

Safe cooking zone

Omega-3,or any unsaturated fat  will oxidise. Heating does speed this up but because cooking only happen sfor a relatively short while there is not the huge change in this rate between ambient temperature of 20C and a low baking/steaming temperature of around a 100C; a  person perceives this as very great – it scalds!  Body temperature is around 36C Raw food is produced at temperatures up to 50 °C, given that absolute zero is -273C and boiling 100C which is around the cooking temp of a Flaxjack you can see that there is significant between cooking linseed in a wet mix in a cool oven and high temperature frying are very different.

Refrigeration is not essential

Much mythology surrounds refrigeration of flaxseed oil to the point where people are prepared to pay a fortune because they think it needs to be kept refrigerated at all times. This is not the case, the cool temperature of freezing  may help to extend the freshness for an extra month or two but actually only makes a little difference. However the freezer is a bit cooler and does help keep the oil a bit fresher for longer; so it is the best place for it but not essential.

Flax carefully produced and cooked in controlled temperatures is healthy

Flax is a traditional food, which carefully produced and cooked is safe, wholesome and healthy as it has been for centuries. you can see that this cooking temperature is not that bad.