Erucic acid

Erucic acid is a monounsaturated omega-9 fatty acid, denoted 22:1ω9, with the chemical formula CH3(CH2)7CH=CH(CH2)11CO2H[1]. It is prevalent in wallflower seed and other plants in the family Brassicaceae, with a reported content of 20 to 54% in high erucic acid rapeseed oil and 42% in mustard oil[1]. Erucic acid is also known as cis-13-docosenoic acid, and its trans isomer is known as brassidic acid[1].

Uses

Erucic acid is a precursor to brassylic acid, a C13-dicarboxylic acid that is used to make specialty polyamides and polyesters[1]. The conversion entails ozonolysis, which selectively cleaves the C=C bond in erucic acid[1]. Amides of erucic acid are used as lubricants and surfactants[1]. Hydrogenation of erucic acid gives behenyl alcohol, CH3(CH2)21OH, a pour point depressant (enabling liquids to flow at a lower temperature), and silver behenate, for use in photography[1].

Sources of Erucic Acid

The name "erucic" means "of or pertaining to Eruca", which is a genus of flowering plants in the family Brassicaceae[1]. Erucic acid is produced naturally (together with other fatty acids) across a great range of green plants, but especially so in members of the genus Brassica[1]. For industrial purposes and production of erucic acid, rapeseed is used; for food purposes a 'low-erucic acid rapeseed' (LEAR) has been developed (canola), which contains fats derived from oleic acid instead of erucic acid[1].

Biochemistry

Erucic acid is produced by elongation of oleic acid via oleoyl-coenzyme A and malonyl-CoA[1]. Erucic acid is broken down into shorter-chain fatty acids in the human liver by the long-chain acyl CoA dehydrogenase enzyme[1].

Health Effects

Studies done on laboratory animals in the early 1970s show that erucic acid appears to have toxic effects on the heart at high enough doses[1]. However, more recent research has cast doubt on the relevance of rat studies to the human health of erucic acid[1]. Rats are unusual in their inability to process erucic acid, and the symptoms in rats caused by a diet with high levels of erucic acid have not been observed in pigs, primates, or any other animals[1]. An association between the consumption of rapeseed oil and increased myocardial lipidosis, or heart disease, has not been established for humans[1]. While there are reports of toxicity from long-term use of Lorenzo's oil (which contains erucic acid and other ingredients), there are no reports of harm to people from dietary consumption of erucic acid[1].

Publication of animal studies with erucic acid through the 1970s led to governments worldwide moving away from oils with high levels of erucic acid, and tolerance levels for human exposure to erucic acid have been established based on the animal studies[1]. In 2003, Food Standards Australia set a provisional tolerable daily intake (PTDI) for an average adult of about 500 mg/day of erucic acid, extrapolated based on "the level that is associated with increased myocardial lipidosis in nursing pigs"[1]. "There is a 120-fold safety margin between this level and the level that is associated with increased myocardial lipidosis in nursing pigs. The dietary exposure assessment has concluded that the majority of exposure to erucic acid by the general population would come from the consumption of colza oil. The dietary intake of erucic acid by an individual consuming at the average level is well below the PTDI; therefore, there is no cause for concern in terms of public health and safety. However, the individual consuming at a high level has the potential to approach the PTDI. This would be particularly so if the level of erucic acid in colza oil were to exceed 2% of the total fatty acids"[1]. Food-grade rapeseed oil[1].

Food Safety Focus

Erucic acid naturally occurs in oil-rich seeds of species of the mustard family (Brassicaceae)[2]. It is found primarily in rapeseed oil and mustard oil[2]. Erucic acid can constitute about 30 – 60% of the total fatty acids of natural rapeseed and mustard seed[2]. It has also been reported in some marine animal oils[2]. Unlike some other monounsaturated fatty acids which may reduce the risk of heart disease, experimental animal studies have shown that exposure to diets with oils containing excessive erucic acid may lead to adverse health effects, with the heart as the principal target organ[2]. The most common effect in the experimental animals is myocardial lipidosis, an accumulation of lipids in heart muscle fibres that may reduce the contractile force of heart muscles[2]. So far, no evidence that dietary exposure of erucic acid is correlated to myocardial lipidosis has been established yet in humans[2]. In order to protect the public's health, local statutory requirements have already been in place to control the level of erucic acid in food[2]. Currently in Hong Kong, all oil or fat and food to which oil or fat have been added shall not contain erucic acid with concentration greater than 5% of the total fatty acids[2].

Low Erucic Acid Rapeseed Oil

In response to the potential safety concerns associated with high levels of erucic acid in rapeseed, efforts have been made to produce cultivars with a low erucic acid trait[2]. Nowadays, rapeseed oils with low levels of erucic acid, including rape oil, colza oil and canola oil, are commercially available[2]. They are produced from low erucic acid oil-bearing seeds of cultivated varieties derived from the Brassica napus L., Brassica rapa L. and Brassica juncea L. species[2]. According to Codex, these oils contain erucic acid level less than 2% of the total fatty acids[2]. The term “Canola” was derived from “Canadian oil, low acid”[2]. It was developed through conventional cross breeding of the rapeseed plant (flowers are yellow with four petals) with unwanted traits removed[2]. Once registered as a trademark in Canada in 1970s, canola has now been recognised and used internationally as a generic term for edible varieties of rapeseed with erucic acid less than 2% in the oil[2]. In fact, low erucic acid rapeseed oils contain low level of saturated fatty acids and has high proportion of unsaturated fatty acids[2]. They can be considered as one of the healthier oils in our diet[2].

Erucic Acid a Possible Health Risk for Highly Exposed Children

Erucic acid is a monounsaturated omega-9 fatty acid, which is present in the oil-rich seeds of the Brassicaceae family of plants, particularly rapeseed and mustard[3]. It mainly enters the food chain when rapeseed oil is used in industrial food processing and home cooking in some countries[3]. It is present in pastries, cakes and infant/follow-on formulae and also in some animal feed (e.g. rapeseed meal)[3]. Although natural forms of rapeseed and mustard contain high levels of erucic acid (over 40% of total fatty acids), levels in rapeseed cultivated for food use are typically below 0.5%[3]. In 1976 the EU set maximum limits for erucic acid as a contaminant in vegetable oils and fats, and foods containing added vegetable oils and fats as an ingredient[3]. Also, specific maximum limits for infant formulae and follow-on formulae were set five times lower than for other foods[3]. EFSA was asked for a new risk assessment as part of a review of these maximum levels[3].

Scientific Follow-up

To address information gaps, the Panel recommended further data collection on erucic acid concentrations in processed foods such as fine bakery wares and food for infants and small children[3]. Levels in animal-derived products (meat, milk, eggs) transferred through animal feed would also be useful[3]. New toxicity studies could also improve understanding on the effects for humans and animals, particularly for target livestock animals and fish[3].

Heart Condition

Tests on animals show that ingesting oils containing erucic acid over time can lead to a heart condition called myocardial lipidosis[3]. This is temporary and reversible[3]. Other potential effects observed in animals – including changes in the weight of the liver, kidney and skeletal muscle[3].

Canola Oil: Healthy or Harmful?

Canola oil continues to be wildly misunderstood[4]. Some worry about the erucic acid, a toxic compound found in rapeseed[4]. But canola oil comes from an edible form of rapeseed, with erucic acid levels well below the U.S. Food and Drug Administration standards[4]. Others warn that 90% of canola oil is genetically modified, though there are no scientific studies to suggest GMOs are harmful[4]. Still others cite the fact that canola oil is used in products such as diesel fuel alternatives and items made with plasticizers, like tires[4]. Plenty of other ingredients appear in inedible items[4]. That doesn't mean they're harmful[4]. If you look at the real story behind canola oil and study its nutrient profile, you'll discover it's actually one of the healthiest oils on the shelf[4].

Canola Oil: Nutrition Facts

There are a number of reasons to include this healthy oil in your diet[4]:

• It’s low in saturated fat[4].
• It’s high in heart-healthy fats[4].
• It has a mild taste[4].
• It has a high smoke point[4].

A Versatile Oil

Whether you’re cooking with high heat or baking tasty treats, canola oil is among the most versatile oils you can choose, and among the healthiest, too[4]. This light-colored, mild-flavored oil is ideal in myriad dishes[4]. The take-home message for your food preparation adventures: Canola oil is a healthy, versatile oil that should be welcome in any of your signature dishes[4].

Citations:

[1] https://en.wikipedia.org/wiki/Erucic_acid

[2] https://www.cfs.gov.hk/english/multimedia/multimedia_pub/multimedia_pub_fsf_162_02.html

[3] https://www.efsa.europa.eu/en/press/news/161109

[4] https://www.henryford.com/blog/2019/11/canola-oil-healthy-or-harmful

[5] https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/erucic-acid