trans fatty acids

from Wikipedia, the free encyclopedia

trans -fatty acids - also TFS for short - are unsaturated fatty acids with at least one trans -configured double bond between two carbon atoms.

In human nutrition, they are found as trans fats in dairy products, meat and industrially produced food.

They are seen as contributing to coronary heart disease ( arteriosclerosis , heart attack ).

The use of the term trans fatty acid is ambiguous:

  • When trans fats are mentioned, one almost always means food fats containing trans fatty acids, i. H. Triglycerides in which one or more trans fatty acids are bonded to glycerol via ester groups .
  • In contrast, unbound , “free” trans fatty acids, usually with 16, 18 or 20 carbon atoms and a carboxy group at one end of the chain-like molecule, are almost never meant.

Occurrence and origin

Bacterial formation

Glycerides of trans fatty acids are found naturally

Unprocessed, unheated vegetable fats are naturally practically free of triglycerides of unsaturated trans fatty acids.

Catalytic partial fat hardening with hydrogen: Above, a triglyceride in an oil with a blue- marked saturated fatty acid residue, a green- marked monounsaturated cis -fatty acid residue and a red- marked triunsaturated fatty acid residue with three cis -configured carbon-carbon double bonds. The triple acylated glycerine ( marked in black ) can be seen in the center of the structural formula above . Below the partially hydrogenated fat, which on the left has a trans -configured carbon-carbon double bond, which was created by the undesired isomerization of a cis -configured carbon-carbon double bond.

Industrial fat hardening

In natural vegetable oils, the unsaturated fatty acid esters are largely in the angled cis form. In industrial processes such as fat hardening , i. H. the conversion of unsaturated double bonds into saturated single bonds by catalytic hydrogen addition , trans -fatty acid esters are formed as by-products (e.g. elaidic acid ):

  • in the rearrangement of monounsaturated (non-hydrogenated) cis fatty acid esters into the trans form, corresponding to an isomerization instead of a successful hydrogenation.
  • polyunsaturated when only partially successful hydrogenation cis - fatty acid ester

In margarine production , the proportion of trans fatty acid ester in the glycerides used to be up to 20 percent due to incomplete fat hardening ; In the meantime, through improved manufacturing techniques, more completely hydrogenated products are available with a far lower proportion (approx. two percent). In addition, it should be mentioned here that the rearrangement is also catalyzed by nitrogen oxides .

Heating and frying at high temperatures

During prolonged heating of vegetable oils with a high content of polyunsaturated cis fatty acid esters (derived from linoleic or linolenic acid ) and also during fat hardening , an isomerization of cis to trans fatty acid esters takes place, e.g. B. when deep-frying .

example

unsaturated fatty acids
trans -fatty acid [( E ) -fatty acid] cis -fatty acid [( Z ) -fatty acid]
Structural formula of elaidic acid Structural formula of oleic acid
Space-filling model of elaidic acid Oleic acid space-filling model
Elaidic acid is a trans fatty acid and occurs as a triglyceride esterified in milk fat . Triglycerides of elaidic acid are also often found in hydrogenated vegetable oils. Elaidic acid has a melting point of 46.5 ° C. Oleic acid is a cis -fatty acid, 55–80% ofwhich isesterifiedas a triglyceride in olive oil . Oleic acid has a melting point of 13.5 ° C.

Analytics

The reliable qualitative and quantitative determination of individual trans-fatty acids from different test materials can be carried out after sufficient sample preparation by capillary gas chromatography and coupling with mass spectrometry . In these cases, special stationary phases , such as DB 23 separation columns with cyanopropylmethylpolysiloxane, must be used to reliably separate the individual fatty acids .

Effect on humans

According to scientific studies, foods with higher proportions of trans fatty acid esters pose an increased health risk. A high consumption of trans fatty acid esters is considered to be a cause of an excessively high LDL level in the blood serum ( low density lipoprotein , also known colloquially as bad cholesterol ) and a drop in the HDL level ( high density lipoprotein , colloquially also known as good cholesterol referred to), which can lead to an increased heart attack and stroke risk due to arteriosclerosis .

People with special dietary habits (frequent consumption of fast food , ready meals, various baked goods and low-quality margarines) consume large amounts of partially hydrogenated fat. It is therefore recommended that adults consume glycerides with no more than two to three grams of trans fatty acid residues per day. A daily intake of triglycerides containing five grams of the trans fatty acid residues increases the risk of coronary heart disease by 25%.

In the opinion of the EU Food Safety Authority, there are no sufficiently conclusive studies available on other health effects of triglycerides of trans fatty acids such as high blood pressure, insulin resistance, cancer risk and allergies . The effects of storage in the cell membranes are unknown , but are generally viewed as an additional health risk.

Occurrence in food

Triglycerides with trans fatty acid residues occur mainly in many fried products and baked goods when partially hydrogenated fats are used. In particular, products such as French fries , biscuits , potato chips and various baking and frying fats contain and contain large amounts of trans fatty acid esters.

In November 1999 the topic of trans fatty acids became known to the wider public. The American Food and Drug Administration (FDA) published the content of trans fatty acids in relation to other fatty acids in the triglycerides of various foods.

Investigations by the Bavarian State Office for Health and Food Safety (January 2007) show that trans fatty acids in Germany v. a. occur in deep-frying fats. The extremely small number of publications on the composition of margarines and the proportions of hydrogenated fats with trans fatty acid esters is striking.

In spreadable and edible fats , the content of triglycerides with trans fatty acid residues is now lower with 1 to 2% of all fatty acid residues. The proportion of trans fatty acids in the triglycerides in certain baked goods ( rusks , crackers , cakes, puff pastries, biscuits, etc.) as well as breakfast cereals with added fat, French fries, dry soups and some sweets still fluctuate widely between less than 1 and 30% - depending on the situation what kind of fats were used for the production.

In a study by Swiss television, puff pastry , deep-frying oil and instant soups were the frontrunners, while Nutella, which was previously the subject of complaint, was only found in low concentrations.

Legal measures

In the EU

There is a limit value for trans fatty acid residues in fats and oils in the European Union for baby food (less than 4% of the total fat content according to the DietVO ) and olive oil. Otherwise there are no limit values ​​for trans fatty acids. According to the Federal Ministry of Consumer Protection, labeling of trans fatty acids is currently being discussed in the relevant EU committees. Due to Regulation (EU) No. 1169/2011 (Food Information Regulation) , it is forbidden under competition law in the EU to indicate low trans fatty acid contents on the packaging.

In Denmark in March 2003 a proportion of less than 2% industrially produced trans fatty acid residues in dietary fats was prescribed by law. Iceland decided in November 2010 to follow the Danish example. In Austria , an ordinance came into effect in September 2009 that sets a limit of two percent trans- esterified fatty acids for fats and fatty oils and for foods with a fat content of more than 20 percent . For foods with a fat content of less than 20 percent, the limit should be four percent. So far there are no legal limit values ​​in Germany and no obligation to declare the proportion of trans fatty acids contained in food . In Germany, according to the Food Labeling Ordinance (LMKV), hydrogenated fats must be declared as "hardened". A joint initiative by the Ministry of Consumer Protection and the food industry to minimize trans fatty acids in food has existed in Germany since mid-2012 . This includes a framework guideline and seven product group-specific guidelines in which ways of further minimization are shown.

From April 2, 2021, foodstuffs may only be sold in the EU if they contain less than 2 g of industrial trans fat per 100 g of fat.

In the populations of a majority of the EU member states, mortality from cardiovascular disease fell sharply between 1980–1984 and 2005–2009, most notably in Denmark, Malta, the Netherlands, Sweden and Great Britain. It is unclear whether a lower intake of industrial trans fatty acids actually contributed to a decrease in cardiovascular mortality of women and men in Denmark towards the end of the period under review 1980–2009.

Other countries

In Switzerland , since April 2008, the sum of trans fatty acids must not exceed 2 g per 100 g of vegetable oil or vegetable fat.

In New York and Philadelphia (USA) the use of trans fats in the preparation of meals in restaurants, snack bars, pubs, cafes and pastry shops has been completely banned by law since mid-2008. In California , trans fats have been banned in restaurants since 2010. Since 2011, the fats may no longer be contained in products offered in retail stores . In June 2015, the FDA decided to ban artificial trans fatty acids in food and remove them from the market within three years. Manufacturers who still want to use trans fats in their products in the future must meet safety regulations and apply to the FDA for permission.

literature

Web links

Wiktionary: Trans fatty acid  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. a b c Food trans fats . In: labor & more . No. 5 , 2007, p. 48 ( PDF ).
  2. K. Kuhnt, M. Baehr, C. Rohrer, G. Jahreis: Trans fatty acid isomers and the trans-9 / trans-11 index in fat containing foods . In: Eur J Lipid Sci Technol. (2011), Vol. 113 (10), pp. 1281-1292. PMID 22164125 .
  3. Hans G. Schlegel General Microbiology p. 397, Georg Thieme Verlag Stuttgart 1981.
  4. a b Trans fatty acids: EFSA panel reviews dietary intake and health effects. European Food Safety Authority (EFSA), August 31, 2004, accessed October 15, 2010 (press release).
  5. Beyer-Walter, Textbook of Organic Chemistry, 23rd Edition, S. Hirzel Verlag 1998 ISBN 3-7776-0808-4
  6. Sabine Krist: Lexicon of vegetable fats and oils. Springer-Verlag, 2012, ISBN 978-3-709-11005-8 . P. 22.
  7. F Beppu, M Asanuma, Y Kawamura, T Nagai, K Yoshinaga, H Mizobe, K Kojima, S Kasatani, K Nagao, A Kubo, J Kanda, N Gotoh: Trans-octadecenoic Acid Positional Isomers Have Different Accumulation and Catabolism Properties in Mice . In: J Oleo Sci. , 2015; 64 (11), pp. 1159-1167, PMID 26521809 .
  8. ^ K Mori, T Ishida, T Yasuda, M Hasokawa, T Monguchi, M Sasaki, K Kondo, H Nakajima, M Shinohara, T Shinke, Y Irino, R Toh, K Nishimura, K Hirata: Serum Trans-Fatty Acid Concentration Isatty Elevated in Young Patients With Coronary Artery Disease in Japan . In: Circ J. , 2015, 79 (9), pp. 2017-2025, PMID 26166015 .
  9. ^ JR Benatar, RA Stewart: The effects of changing dairy intake on trans and saturated fatty acid levels - results from a randomized controlled study. In: Nutr J. , 2014 Apr 3, 13, p. 32, PMID 24708591 .
  10. AR Fardin-Kia, P Delmonte, JK Kramer, G Jahreis, K Kuhnt, V Santercole, JI Rader: Separation of the fatty acids in menhaden oil as methyl esters with a highly polar ionic liquid gas chromatographic column and identification by time of flight mass spectrometry. In: Lipids , 2013 Dec, 48 (12), pp. 1279-1295, PMID 24043585 .
  11. ^ A Li, Y Ha, F Wang, W Li, Q Li: Determination of thermally induced trans-fatty acids in soybean oil by attenuated total reflectance fourier transform infrared spectroscopy and gas chromatography analysis . In: J Agric Food Chem. 2012 Oct 24, 60 (42), pp. 10709-10713, PMID 23025355
  12. ^ Dariush Mozaffarian, Martijn B. Katan, Alberto Ascherio, Meir J. Stampfer, Walter C. Willett: Trans Fatty Acids and Cardiovascular Disease . In: Massachusetts Medical Society (Ed.): New England Journal of Medicine . Vol. 354, No. 15 , 2006, p. 1601-1613 , doi : 10.1056 / NEJMra054035 .
  13. Trans Fatty Acids: The Risk of Heart Attack in Puff Pastry . ( Memento from February 27, 2014 in the Internet Archive ) MTW, broadcast on January 4, 2007
  14. Questions and Answers on Trans Fat Proposed Rule. US Food and Drug Administration / Center for Food Safety and Applied Nutrition / Office of Food Labeling, November 1999, archived from the original on April 13, 2008 ; Retrieved October 15, 2010 (English, 64 FR 62746).
  15. Importance of trans-fatty acids in nutrition: legal situation and current results of the LGL. Bavarian State Office for Health and Food Safety, July 14, 2008, accessed on October 15, 2010 .
  16. Michael Kempf: trans fatty acids: A risk assessment . 2003 ( PDF ( Memento from August 28, 2006 in the Internet Archive ) - seminar paper, University of Würzburg).
  17. ↑ Asked about experts: How dangerous are trans fatty acids? - It depends on the amount. Margarine Institute for Healthy Eating V., archived from the original on February 24, 2011 ; accessed on October 15, 2010 (assessments of interactions with trans fatty acids in the organism).
  18. Trans fatty acids are undesirable in the diet - too much fat too. (PDF; 59 kB) Opinion No. 015/2006. Federal Institute for Risk Assessment , January 30, 2006, accessed October 15, 2010 .
  19. Hidden Killer Fats: Eating as a Matter of Chance. In: Kassensturz . Swiss television , September 19, 2006, archived from the original on April 11, 2014 ; Retrieved October 15, 2010 .
  20. trans fatty acids are undesirable in the diet; too much fat too . (PDF; 59 kB). Federal Institute for Risk Assessment (Germany).
  21. BEK nr 160 of 11/03/2003 - Bekendtgørelse om indhold af transfedtsyrer i olier and fedtstoffer mv (Transfedtsyrebekendtgørelsen).
  22. Reglugerð no. 1045/2010 to hámarksmagn transfitusýra í matvælum. New Icelandic rules for trans fats. In: Norden.org. November 11, 2010, archived from the original on January 17, 2011 ; Retrieved November 12, 2010 .
  23. Federal Ministry of Health (Austria): Trans-Fatty Acids Regulation .
  24. Trans fatty acids: Fixed regulation for stricter trans fat limit values. In: derStandard.at. August 20, 2009, accessed October 15, 2010 .
  25. trans fatty acids and their influence on health www.dge.de ( German Society for Nutrition ), accessed on January 6, 2019.
  26. Guidelines for the further minimization of trans fatty acids in food presented . ( Memento from September 26, 2015 in the Internet Archive ) BMEL, press release No. 184, June 20, 2012.
  27. Background . ovid-verband.de.
  28. Guidelines for further minimizing trans fatty acids in foods . Federation for food law and food science .
  29. n-tv NEWS: EU Commission sets binding upper limit for trans fats. Retrieved June 13, 2019 .
  30. Regulation (EU) 2019/649 of the Commission of April 24, 2019 amending Annex III of Regulation (EC) No. 1925/2006 of the European Parliament and of the Council on trans fatty acids other than those naturally found in fat of animal origin
  31. Melanie Nichols, Nick Townsend, Peter Scarborough, Mike Rayner: Trends in age-specific coronary heart disease mortality in the European Union over three decades: 1980–2009 . In: European Heart Journal (2013) 34, pp. 3017-3027, doi: 10.1093 / eurheartj / eht159 .
  32. Steen Stender, Arne Astrup, Jørn Dyerberg: T racing artificial trans fat in popular foods in Europe: a market basket investigation . In: British Medical Journal (2014), Volume 4, Issue 5.
  33. Art. 3 Para. 8 of the Ordinance of the FDHA of 23 November 2005 on edible oil, edible fat and products made from them .
  34. Art. 7 Paragraph 6 of the Ordinance of the FDHA of 23 November 2005 on edible oil, edible fat and products made from them .
  35. ^ Poison: New York Bans Trans Fats in Restaurants. In: Welt Online. December 6, 2006, accessed October 15, 2010 .
  36. Complying with the Philadelphia Trans Fat Ban. (PDF; 1.4 MB) In: www.phila.gov. December 2007, accessed December 25, 2010 .
  37. ↑ A blow to the food industry: California bans fats that are hazardous to health. In: Spiegel Online. July 26, 2008, accessed October 15, 2010 .
  38. USA wants to ban trans fats in food. stern.de, June 21, 2015, accessed on June 22, 2015 .
  39. 78 FR 67169 (PDF; 257 kB). FDA Ruling Would All but Eliminate Trans Fats. In: NY Times. November 7, 2013, accessed November 8, 2013 . FDA calls for ban on artery-clogging trans fats in processed foods. In: PBS Newshour. November 7, 2013, accessed November 8, 2013 .
  40. Saskia Gerhard: Transfett - Creamy, fatty, unhealthy . Zeit Online , June 2015; Retrieved September 3, 2015.
  41. FDA Cuts Trans Fat in Processed Foods . fda.gov; Retrieved September 3, 2015.