All oils are composed, in varying proportions, of three types of fatty acids: saturated , monounsaturated and polyunsaturated . They are classified according to the predominant fatty acids. Canola (or rapeseed) oil is largely made up of monounsaturated fats, known for their beneficial effects. In addition, other active compounds present in this oil can bring health benefits.
Active ingredients and properties
Canola oil contains over 85% unsaturated fatty acids (monounsaturated and polyunsaturated). Unsaturated fats reduce blood lipid levels when they replace saturated and trans fats in the diet 1 , 2 . For example, they lower the risk of coronary heart disease by lowering blood cholesterol 3 .
In the United States, the labeling of canola oil bottles and certain products that contain canola oil may highlight the potential beneficial effects of monounsaturated fats against coronary heart disease. The Food and Drug Administration (FDA), the US agency responsible for food control, has authorized this health claim 5 . However, it should be noted that this claim must be accompanied by several important nuances, including the fact that it is based on limited and inconclusive scientific data. In Canada, this claim is not permitted.
Canola is a variety of rapeseed, a plant in the cruciferous family. Canola is widely grown in Canada, particularly for oil. Compared to olive oil, refined canola oil has a more neutral taste and is more affordable.
A large study was conducted with men suffering from coronary artery disease. The results indicate that a Mediterranean diet combined with a canola oil-based margarine (to replace butter and cream) can reduce recurrences of coronary heart attacks by 50% to 70% , compared to a low-fat diet. 6 . Most clinical studies show that canola oil lowers LDL (“bad”) cholesterol and total 7-9 and triglyceride 10 levels in the blood compared to a diet high in saturated fat.
Monounsaturated fatty acids . Like olive oil, canola oil is particularly rich in monounsaturated fatty acids . These represent almost 60% of the fat content of canola oil. The effects related to the consumption of monounsaturated fats have been described above.
Polyunsaturated fatty acids . Canola oil stands out from olive oil and certain other oils by its high content of polyunsaturated fats which represent almost a third of its total fat. In general, these fatty acids reduce blood cholesterol levels, particularly LDL cholesterol (“bad” cholesterol), when they replace saturated fatty acids in the diet 11 . They thus help reduce the risk of coronary heart disease 12-15 .
- Alpha-linolenic acid . Alpha-linolenic acid (ALA) is part of the family of omega-3 polyunsaturated fats. As it cannot be manufactured by the body, it is said to be essential , because it must be supplied by food. In the body, it can transform into long chain fatty acids , which are beneficial for cardiovascular health. Canola oil is one of the oils rich in ALA (9% of its total fat content), along with soybean oil (7%) walnut oil (10%) and linseed oil (56 %). The protective effect of omega-3 against coronary heart disease is well known. Some observational studies have shown the effectiveness of LAA in this regard . 16 The optimal supply of ALA would be around 2 g per day17 : 1 tsp. (15 ml) canola oil provides 1.3 g of alpha-linolenic acid.
Antioxidants . Like most vegetable oils, canola oil contains antioxidants.
- Vitamin E . Canola oil contains 7 to 17 times more vitamin E than olive oil, about 17 mg per 15 ml serving. More than half of this vitamin E is present in the form of gamma-tocopherol 18 . The refinement and deodorization stages of the oil partially reduce the vitamin E content of vegetable oils. This loss is often compensated for by adding synthetic vitamin E to the oil. According to one study, a diet rich in canola oil increases blood gamma-tocopherol levels compared to a standard diet or one rich in saturated fat . 19 Some research shows that high levels of gamma-tocopherol in the blood may have a protective effect against prostate cancer20 . However, more studies are needed before establishing a link between the consumption of canola oil and cancer prevention.
- Canolol . An antioxidant called canolol was recently discovered in unrefined canola oil . 21 This compound prevents oxidation of lipids and proteins in vitro. New studies are needed to determine if these effects can occur in the body. It should be noted that most of the canola oils on the market are refined: since refining causes the loss of certain compounds, their antioxidant effect may therefore be less than that of unrefined oils 22 .
Phytosterols . Due to their close chemical structure, phytosterols reduce the absorption of cholesterol in the intestine, which lowers blood cholesterol levels. Canola oil contains about 100 mg of phytosterols per 15 ml (1 tablespoon) serving, two to seven times more than olive oil 23,24 . According to some scientific data, the quantity of phytosterols in the blood is higher after the consumption of canola oil than olive oil 23 , 24 .
A meta-analysis of 41 clinical trials found that daily intake of 2 g of plant sterols reduce by 10% the rate of LDL cholesterol ( “bad”) cholesterol. This reduction can reach 20% as part of a diet low in saturated fat and cholesterol 25. This amount of 2 g per day is practically impossible to achieve only through food. Currently, the marketing of foods fortified with phytosterols is permitted in the United States and Europe, but not in Canada. Foods that naturally contain it, such as canola oil, are still good for cardiovascular health, even if their content is low compared to the dose required to obtain a beneficial effect.
|Is canola oil antioxidant?||We know that oils have antioxidant potential, but their TAC index is not currently available.|
|Is canola oil acidifying?||Data not available.|
|Canola oil has a high glycemic load?||Data not available.|
Most important nutrients
Vitamin K . Canola oil is a good source of vitamin K. Vitamin K plays an important role in blood clotting. It also contributes to the formation of bones. In addition to being found in food, vitamin K is also produced by bacteria present in the intestine. Vitamin K deficiencies are therefore very rare.
Vitamin E . Canola oil is a source of vitamin E. Unrefined oils generally contain more of it than refined oils. Vitamin E is a major antioxidant. It protects the membrane that surrounds the cells of the body, especially red blood cells and white blood cells (cells of the immune system).
|What is a “portion” of canola oil worth?|
|Weight / volume||Canola oil (rapeseed), 14 g (15 ml)|
|– saturated||1.0 g|
|– monounsaturated||8.4 g|
|– Omega 3*||1.3 g|
|Dietary fiber||0 g|
Source : Health Canada. Canadian Nutrient File , 2007.
* Alpha-Linolenic Acid (ALA)
Canola and GMOs
Part of the canola grown in Canada is genetically modified. This practice is intended to make canola resistant to herbicides, which makes it easier to control weeds. It helps keep the cost of canola oil production relatively low. Oils extracted from genetically modified canola, however, are not considered genetically modified organisms (GMOs). Indeed, the typical components of GMOs ( modified DNA and associated proteins) are not found there, except in the state of traces. Nevertheless, people who prefer to avoid consuming products from genetically modified crops can now find organic canola oil on the market.
|Cardiovascular health: olive or canola oil?
Olive oil and canola oil are equivalent in their beneficial effects on blood lipids , according to the results of several intervention studies 7,26,27 comparing these two oils. Other tests indicate that canola oil is slightly higher 23,28 . Their different contents in certain types of fat (alpha-linolenic acid, phytosterols and squalenes) could partly explain the better results of canola oil 29 .
In addition, the consumption of olive oil further prevents the oxidation of LDL-cholesterol (“bad” cholesterol) 7 and the formation of blood clots 30 , two protective factors against cardiovascular disease.
In summary, both oils are beneficial for cardiovascular health.
In the food industry, canola oil can be hydrogenated or partially hydrogenated for better preservation and to be able to withstand high cooking temperatures. Such an oil can be used in margarines, for frying or in various food preparations (pastries, chips, crackers, etc.). It is sometimes mixed with other oils, hydrogenated or not.
Partially hydrogenated oils contain trans fats , which have harmful effects on blood lipids and cardiovascular health 31,32 . By reading the label of food products, one can spot those that contain them and avoid them as much as possibl
Canola (rapeseed) over time
|The word ” rapeseed ” comes from the Dutch koolzaad (or coolzaad ) which literally means “cabbage seed”. It appeared in the French language written in 1671. The word ” canola ” is a neologism created by Canadian rapeseed producers. They wanted to highlight the difference between traditional rapeseed, rich in erucic acid and glucosinolates, and the new varieties they crossed, which are poorer in these two substances. The word would mean Canadian Oil or, again, a contraction of Can adian O il L ow A cid .|
The origin of rapeseed remains unclear. It could result from a spontaneous cross between cabbage ( Brassica oleracea ) and the shuttle ( B. rapa ) or between related species. This crossing would have occurred somewhere around the Mediterranean basin. The plant then spread to India and China to the east, and to Europe in the west. In Asia, about 2,000 years ago, the oil extracted from the seeds of various Brassica species was used for lighting. This custom is widespread in Europe between the XIII th century and the XVI th century.
Asia has long consumed large quantities of rapeseed oil in the diet. In the West, with the exception of a few regions, most of its industrial use, including that of lubricant for ships, was limited to, particularly during the Second World War. It was during this time that Argentine rapeseed was introduced into Canada for large-scale production under the War Measures Act.
Composed under the magnifying glass
|Oil from rapeseed varieties rich in erucic acid is used in the production of industrial lubricants, plastics, soaps and cosmetics. Among the non-food uses of rapeseed oil, it is the production of biofuel that arouses the most interest, given the immense potential that this market currently presents.|
In the late 1950s, a study in laboratory animals indicated that erucic acid – the rich content of rapeseed oil – had harmful consequences on heart health. He is therefore banned in several places. Following numerous tests carried out over the next 18 months, it has been found that erucic acid has in fact no harmful effect: the prohibitions are therefore canceled.
In the early 1970s, the debate over the safety of erucic acid was revived at an international conference, although there was still no evidence of its potentially toxic effects. In France, it is causing the decline in the consumption of rapeseed oil.
Meanwhile, another discovery is made about oil cake, the residue from oil making. This feed, which is intended for livestock, is rich in glucosinolates . However, these substances are considered anti-nutritional, that is to say that they slow or stop growth. Encouraged by the government, Canadian researchers are carrying out breeding work which will lead to the production of varieties low in erucic acid and glucosinolates. From this work was born canola .
|In 1978, the Western Canadian Oilseed Crusher’s Association registered the trade mark Canola . She sold it in 1980 to the Canola Council of Canada, a not-for-profit corporation that represents the interests of the canola industry.|
In nearly 25 countries, the term “canola” and the logo representing the canola flower are licensed by the Canola Council of Canada. This gives the right to use them on the packaging of canola products provided that certain standards are met , particularly with regard to the content of erucic acid and glucosinolates. However, “canola” has become a generic term as an agricultural product.
In 1985, the American FDA granted canola oil GRAS ( generally recognized as safe ) status. In 2006, it even authorized the food industry to display, in a nuanced manner, the potential beneficial effects of canola oil on the label of their products (see the Active ingredients and properties section).
A growing production
|What about rapeseed leaves?
They can be found in Asian grocery stores. They are eaten like turnip greens, cabbage and mustard, all of which belong to the Brassica genus .They are widely consumed in Asia, as well as in certain regions of Africa where, in the opinion of experts, they can help to reduce vitamin deficiencies. They are also used in Spanish and Portuguese cuisine, as well as in the southwest of France.
The flowers produce a large amount of nectar which the bees transform into clear honey, very rich in glucose.
The main producers of rapeseed / canola are China, the European Union, Canada and India. According to the United States Department of Agriculture, from 1999 to 2004, canola and rapeseed were the third largest oil crop in the world after soybeans and oil palm, and the second for protein production.
Rapeseed oil is omnipresent in Europe where it is the first oil for human consumption. Canola oil is mainly found on the shelves of North American grocery stores. It is also used in the composition of margarines , mayonnaises and a host of processed products .
The harmful effects of trans fats have been widely publicized in the media. As a result, both in the United States and in Canada, the food industry is moving away from partially hydrogenated soybean oil – which is also richer in saturated fat – in favor of canola oil.
This new outlet could propel it to the first or second place in the world for consumer oils. By some estimates, in the United States alone, the food industry uses 5 billion pounds of oil (2.3 million tonnes) annually. For Canada, this is great news. In fact, the country remains the world center for canola research and its culture occupies more than 13 million acres, mainly in the Prairies.
Almost all of the canola oil found in North American commerce is refined . This is also the case for rapeseed oil in Europe. In addition, in North America, it comes mainly from transgenic plants.
There is, however, unrefined rapeseed or canola oil that does not come from transgenic plants. It is yellow-green in color, slightly amber. More expensive than refined oil, it has a characteristic flavor reminiscent of almonds, asparagus and artichokes . In contrast, the taste of refined oil is neutral and its color is much less pronounced.
Unrefined oil : it is recommended not to use it for cooking at high temperature, because its smoke point is quite low. Its characteristic flavor goes well with all kinds of preparations:
- on warm salads , pasta or green salads, especially arugula, married to lemon juice or a good balsamic vinegar;
- as an accompaniment to raw salmon ;
- in dips , Indian raïtas, hummus, baba ganoush, etc.
- instead of olive oil, in mayonnaise , anchovy, piperade, tapenade, etc.
- on pistou pasta , grilled or stuffed peppers;
- add a drizzle on potatoes or other steamed vegetables or in soups;
- on oven roasted root vegetables ;
- in baking , in pancake, cake, cookie, muffin, pie, square, etc.
Refined oil has a high smoke point and can therefore be used for deep frying, but unlike olive or peanut oil, it cannot be reused.
Leaves. Cook them as you would for spinach.
Particularly stable, refined oil can be stored at room temperature. Keep unrefined oil in a cupboard in a cool, dry place away from light. Once opened, keep it in the refrigerator. For the longer term, it can be frozen.
Like all field crops, rapeseed has little place in home gardens. However, organic gardeners plant them on the edge of their flowerbeds to attract pollinating insects to the garden. It is also used to “smash” heavy soils, like mustard and radish. It also serves as a ground cover in winter, thus helping to limit nitrogen leaching. In spring, it is buried and it then constitutes a green manure.
Unfortunately, it is virtually impossible in Canada to find rapeseed / canola seeds that are not contaminated with transgenic rapeseed. People who absolutely want to grow organically should therefore avoid this plant and fall back on mustard, radish or turnip. However, if you wish to let these last plants rise in order to collect the seeds, it is better to ensure that there is no rapeseed / canola crop in the area. Otherwise there is a risk of causing spontaneous crossbreeding and transgenic contamination.
Ecology and environment
In Canada, in 2004, 77% of canola acreage was planted with transgenic varieties, according to the Quebec government’s GMO site. Unofficial data indicates that, in Quebec, this rate is now 95%. This makes many observers say that it is virtually impossible to obtain certified organic canola in Canada – or organic canola honey – that is to say that is not contaminated with GMOs.
The majority of researchers recognize this today: the risk of gene dispersal is high in rapeseed / canola, because it is botanically very close to many wild species found in agricultural areas. Crosses between all these plants are therefore possible. A variety of transgenic canola can thus fertilize non-transgenic canola plants that grow in a neighboring field. It can also fertilize related cultivated species, such as mustard or cabbage that is grown for seed production.
There is also a risk that GM canola will contaminate related weed species, which can make them resistant to herbicides. In fact, most of the transgenic rapeseed varieties have been modified to be resistant to herbicides – rapeseed being particularly ineffective in competing with weeds, especially grasses.
Gene dispersal can occur through canola seeds that escape during planting or harvesting. The seeds may then germinate in the field in the following years, or much further when transported by birds or other animals. This dispersion makes it very difficult to monitor contamination. The dissemination can also pass through pollen, which remains viable for a very long time and which can fertilize plants located several kilometers away.
In France, where transgenic rapeseed is prohibited, researchers from the National Institute for Agronomic Research (INRA) have studied the question of dispersal. They concluded in 1998, after ten years of work, that “the risks of dissemination by pollen and seeds exist. Transfer to wild populations seems possible, but with a low frequency ”. According to them, further work was needed to assess the risks.
INRA researchers carried out simulations from models and consulted experts. In 2006, these researchers concluded that the coexistence of GMO rapeseed / canola crops and non-GMO crops would require drastic agricultural measures. In addition, these measures should be applied in the long term to ensure that the level of GMOs in non-GMO seeds does not exceed the current regulatory threshold of 0.9%. This is explained, they say, by the pattern of cross-pollination of canola and the persistence of seeds in the soil for long periods.