Erucic acid

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Erucic acid
Erucic acid
Chemical name Z-13-Docosenoic acid
Other names Erucic acid
Chemical formula C22H42O2
Molecular mass 338.56 g/mol
CAS number [112-86-7]
PubChem 5281116
Density 0.860 g/cm3
Melting point 33.8 °C
Boiling point 381.5 °C (dec.)
SMILES OC(CCCCCCCCCC/C=C\CCCCCCCC)=O
Disclaimer and references

Erucic acid is a monounsaturated omega-9 fatty acid, denoted 22:1 ω-9. It is prevalent in rapeseed, wallflower seed, and mustard seed, making up 40 to 50 percent of their oils. Erucic acid is also known as cis-13-docosenoic acid and the trans isomer is known as brassidic acid.

Contents

[edit] Uses

It has many of the same uses of mineral oils but with the advantage that it is more readily bio-degradable. Its high tolerance to temperature makes it suitable for transmission oil. Its ability to polymerise and dry means it can and is used as a binder for oil [paint]s. Erucic acid silver salt has be found to useful modify the properties of photographic film. It is widely used to produce emollients, especially for skin and healthcare products. Like other fatty acids it also gets converted into surfactants. It is especially valued in tribology as a superior lubricant. When used in the manufacture of plastic films it migrates to the surfaces and so resists each films sticking to its neighbor. Being a high calorific value hydrocarbon with a very low flash point and high cetane rating and good lubrication qualities it can be a valuable component of bio-diesel. When converted into Behenyl alcohol (CH3(CH2)20CH2OH) it has many further uses such as a pour point depressant, enabling liquids to flow at a lower temperature and Behenyl silver for use in photography.[1]

[edit] Sources of erucic acid

It is produced naturally (together with other fatty acids) across a great range of green plants but especially so in members of the brassica family. It is highest in some of the rapeseed varieties of brassicas. Kale and mustard being some of the highest, followed by Brussels spouts and broccoli. For industrial purposes a High Erucic Acid Rapeseed (HEAR) has been developed. These cultivars can yield 40% to 60% of the total oil recovered as erucic acid.

[edit] Metabolism of erucic acid

Erucic acid is broken down in the human body by enzymes (long-chain acyl-coenzyme A (CoA) dehydrogenase) produced in the liver, which chop it into shorter chain fatty acids, which are in their turn broken down. For more information on this see: Lipid metabolism. Based on animal studies in adult pigs and piglets it can be reasonable presumed that in human infants which have not yet been weaned, these particular enzymes are in short supply (as mothers milk is the normal food source during this period) and so babies should not be given foods high in erucic acid. Before low erucic acid oil rapeseed (LEAR & Canola) cultivars were developed this situation was un-likely to present a realistic danger since erucic acid only occur in nature along with bitter tasting compounds that infants instinctively reject. In some of the new varieties the bitterness or pungency has been considerably reduced to make it more palatable to humans and cattle. Studies on rats have shown that they are less able to digest vegetable fats (whether or not they contain erucic acid) than humans and pigs.[2][3][4] Chariton et. al. suggests: “Inefficient activation of erucic acid to erucyl CoA and a low level of activity of triglyceride lipase and enzymes of betaoxidation for erucic acid probably contribute to the accumulation and retention of cardiac lipid.”[5] Before this was fully understood however, it lead to much misunderstanding which continues to be repeated until this day. See below.

[edit] Health effects

No negative health effects have ever been documented in man although it is advisable not to give un-weaned babies, foods containing erucic acid for the reasons given above.[6]

Epidemiological studies suggest that in regions where mustard oil is still used traditionally that mustard oil exhibits some protection against cardiovascular diseases. In this sense 'traditional' means that the (a) oil is used fresh and (b) vegetable fats only counts as a small percentage of the total calorific intake. Whether this effect is due to the nature of erucic acid per se to make the blood platelets less sticky, or the presences of a reasonable high percentage of α-linolenic acid, or a combination of properties of fresh unrefined oil, is as yet, uncertain. Care needs to be taken with such epidemiological studies to exclude early deaths from other causes slewing the results. Fortunately, early non symptomatic coronary disease is readably detectable at post mortem and is absent in the mustard oil cohorts tends to add weight to the hypothesis that mustard oil is protective. [7]

A four-to-one mixture of erucic acid and oleic acid constitutes Lorenzo's oil; an experimental treatment for a rare neurobiology disorder adrenoleukodystrophy.

[edit] Health concerns

 The neutrality of this section is disputed.
Please see the discussion on the talk page.

Before the days of 'genetic engineering', plant breeders were aiming to produce a blander multi-purpose oil from oil rapeseed which would appeal to a larger market by making it more acceptable to cattle and other livestock. Unfortunately, whilst it was easy to breed out much of the pungent tasting glucosinolates, one of the dominant erucic acid genes would get stripped out of the genome as well, greatly reducing its valuable erucic acid content. Serendipitously for the plants breeders though, studies on rats show lipodosis problems when fed high quantities of erucic acid.[8] Although later trials showed that rats had the same problems with other vegetable fatty acids. [9] This was on account that they are poor at metabolising them.[10] The plant breeding industry ploughed on regardless because low erucic acid was now its Unique selling proposition over that of all its competitors. The thalidomide tragedy showed the importance and value of good epidemiological studies over that of animal studies but without any epidemiological data at all, food science was hijack by this industrial sector to suit its own purposes. Even when animal studies failed to show negative events the studies were repeated under ever more fanciful scenarios. Finally, even though neonate piglets have a limited ability to absorb these fats, they had their normal sows milk totally denied them and were fed instead solely on rapeseed oil for one hundred percent of their calorific needs.[11] Even then, the lipidoses suffered by the piglets proved to only be a transient effect, the liver automatically responded by increase the necessary enzyme levels to cope with the unusual diet and the lipidoses subsided; which is another fact always left out of the sales and marketing accounts. A resent example of more sales and marketing hyperbole was their reporting that a study that recorded the higher rates of lung cancer in those peoples who population cook over inefficient and smoky solid fuel fires and stoves. It was reported by the low erucic oil industry in such a way as to imply that these cancers might really be caused not by the smoke but by the oil, so why take the risk. The possibility of smoke from over heated oil has been considered and ”No consistent differences in risk patterns emerged with regard to the effects of the different types of frying or the use of a specific type of cooking oil.” [12]

Since the public food regulator were set up before varieties of plants could be 'owned' and that they have become biased towards protecting industrial interests, there remains no remedy for the damage being down by this of abuse of science.[13] Nor is there any clear way to stop its distortions slowly creeping into the allied fields of organic chemistry, biology, human physiology, medicine etc. What is the value of trails that would most likely show very harmful effect to total diet substitutions by Brussels spouts, kale, cods liver, hare and so on.[14][15] [16] If the same safety factor (120) was applied to fluoride then all natural spring water would be deemed not fit to drink. Finally, erucic acid, like any other vegetable oil, has a high calorific value. Further, it has only been separated from its seeds' protein rich (but energy poor) meal very recently in mankinds' evolution. Therefore, it and all vegetable oils should only contribute a small amount of an individuals daily calorific needs.[citation needed]

[edit] References

  1. ^ Economic Research Service, USDA ( September 1996) Crambe, Industrial Rapeseed, and Tung Provide Valuable Oils . Fats and Oils, Industrial Uses; Page 18. Retrieved 2007-01-29
  2. ^ Hulan HW, Kramer JK, Mahadevan S, Sauer FD.(1976)Relationship between erucic acid and myocardial changes in male ratsLipids. 1976 Jan;11(1):9-15. Retrieved 2007-02-14
  3. ^ Kramer JK, Farnworth ER, Thompson BK, Corner AH, Trenholm HL.Reduction of myocardial necrosis in male albino rats by manipulation of dietary fatty acid levels. Lipids. 1982 May;17(5):372-82. Retrieved 2007-02-14
  4. ^ de Wildt DJ, Speijers GJ(1984)Influence of dietary rapeseed oil and erucic acid upon myocardial performance and hemodynamics in rats.Toxicol Appl Pharmacol. 1984 Jun 15;74(1):99-108 Retrieved 2007-02-14
  5. ^ K. M. Chariton, A. H. Corner, K. Davey, J. K. G. Kramer, S. Mahadevan and F. D. Sauer (1975) Cardiac Lesions in Rats Fed Rapeseed Oils Canadian Journal of comparative Medicine. Vol. 39- July, 1975 page 267. Retrieved 2007-02-14
  6. ^ Food Standards Australia New Zealand (June 2003) Erucic acid in food : A Toxicological Review and Risk Assessment . Technical report series No. 21; Page 4 paragraph 1; ISBN 0 642 34526 0, ISSN 1448-3017
  7. ^ Tanuja Rastogi (2004) Diet and risk of ischemic heart disease in India. American Journal of Clinical Nutrition, Vol. 79, No. 4, 582-592, April 2004. Retrieved 2007-01-29
  8. ^ K M Charlton, A H Corner, K Davey, J K Kramer, S Mahadevan, and F D Sauer (1975)Cardiac lesions in rats fed rapeseed oils.Can J Comp Med. 1975 July; 39(3): 261–269. Retrieved 2007-01-29
  9. ^ C E Neat, M S Thomassen, and H Osmundsen. Effects of high-fat diets on hepatic fatty acid oxidation in the rat. Isolation of rat liver peroxisomes by vertical-rotor centrifugation by using a self-generated, iso-osmotic, Percoll gradient. Biochem J. 1981 April 15; 196(1): 149–159. Retrieved 2007-1-29
  10. ^ Kramer J K, Hulan H W, Trenholm ,H L and Corner A H (1979) Growth, lipid metabolism and pathology of two strains of rats fed high fat diets.J Nutr. 1979 February;109(2):202-213. Retrieved 2007-01-29
  11. ^ Kramer J K, Hulan H W, Trenholm ,H L and Corner A H (1979)Growth, lipid metabolism and pathology of two strains of rats fed high fat diets.J Nutr. 1979 February;109(2):202-213. Retrieved 2007-01-29
  12. ^ S Kurt, Baan R, Grosse Y, Secretan B, (2006) [ehs.sph.berkeley.edu/krsmith/publications/2006%20pubs/Lancet-Oncology3.pdf Carcinogenicity of household solid fuel combustion and of high-temperature frying]. WHO International Agency for Research on Cancer Monograph Working Group. PDF 52kb. Retrieved 2007-01-29
  13. ^ Lenzer J (2004)FDA's counsel accused of being too close to drug industry BMJ 2004;329:189 (24 July), doi:10.1136/bmj.329.7459.189 Retrieved 2007-01-29
  14. ^ Smith, R H (1980) Kale poisoning: The brassica anemia factor. Vet. Rec., 107: pages 12-15.
  15. ^ Hutchison T W (1977) Onions as a cause of Heinz body anaemia and death in cattle.Can Vet J. 1977 December; 18(12): 358–360.
  16. ^ Canadian biodiversity information facility General poisoning notes Government of Canada. Retrieved 2007-01-29

[edit] See also

[edit] External links

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