SVIBOR - Project code: 3-01-110

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Project code: 3-01-110


MODULATION OF LIPID MOLECULES: FOOD AND ENVIRONMENT INFLUENCE


Main researcher: POPOVIĆ, MILIVOJ (38190)


Assistants
Type of research: applied
Duration from: 01/01/91. to 12/31/94.
Papers on project (total): 20
Papers on project quoted in Current Contents: 8
Institution name: Medicinski fakultet, Zagreb (108)
Department/Institute: Departement of chemistry and biochemistry
Address: 10 000 Zagreb, Šalata 3, Hrvatska
City: 10000 - Zagreb, Croatia
Communication
Phone: 385 (0)1-4566-940
Fax: 385 (0)1-272-050
Summary: In this project the effect of unconventional diets on fatty acid changes in both tissues and body fluids was investigated. One of the aims of these investigations was to determine the effect of a fat-free protein-carbohydrate diet on the rate of fatty acid desaturation. The problem of the saturation and possible elongation of fatty acids affected by medium-chain fatty acid triacylglycerols (MCT) diets was investigated, too. Two additional directions of investigations were also planned within this project: (a) the investigation of the effect of dietary n-3 and n-6 essential fatty acids and (b) the effect of lipophylic xenobiotics, on fatty acids of different lipid classes in rat. By summarizing the results obtained so far it can be concluded: (1) Low-fat protein-carbohydrate diets induce a significant desaturation (increase of 16:1 n-7 fatty acid) in particular lipid classes (TG, FFA, PC and PE). This phenomenon was not noticed in total lipids of the investigated rat tissues (liver, brain, lungs, kidneys) indicating a specific dietary interaction of the biosynthesis of particular lipid class. (2) The effect of dietary MCT revealed an increase of saturated fatty acids and a very slight fatty acid chain elongation in the above mentioned lipid classes of the above said tissues of the rat. No essential changes in the overall composition of total lipids was noticed suggesting the same conclusion as above mentioned for low-fat diets.

Keywords: lipids, modulation, nutrition, environment, diet, fat free, medium chain, essential fatty acids

Research goals: The aim if these investigations was to determine thepossibilities of modulations of fatty acids by diets withdifferent fat (oil) compositions. Therefore rats were fed twodifferent diets: (a) low-fat diet (LFD) containing 0.6% fat and(b) medium-chain triacylglycerol (MCT) diet with 18.7% MCT. After14 days, fatty acids of total lipids and particular lipid classes(TG=triacylglycerols, FFA=free fatty acids,PC=phosphatidylcholine, PE=phosphatidylethanolamine) wereanalyzed. On the basis of the obtained data it was possible tocompare the effects of both LFD and MCT-diet on fatty acids ofthe following organs: liver, brain, lungs and kidney. Theobtained differences were expressed as desaturation factor (DF)for LFD and saturation factor (SF) for MCT-diet, respectively. Onthe basis of the obtained results for LFD (also known as fat-freediet) in all of the investigated lipid classes (TG, FFA, PC, PE)an increase of 16:n-7 fatty acid was found. At the same time adecrease of polyenoic fatty acids of the C-18 series was noticed.This might trigger an inhibitory effect in the synthesis of themediators in the eicosanoides series. MCT-diet affected anoverall saturation of fatty acids (SF increase) in all of theabove mentioned lipid classes. This was predominantly expressedas a certain increase of palmitic and stearic acid. Mostobviously, this was present in the PC fraction of the lungs,where the MCT-diet induced an increase of 152% of palmitic acid. Additional investigations have shown that a "tender effect" of fatty acid changes was found. This could probably enable the cell a relatively unchanged membrane fluidity. Fatty acid changes of particular lipid classes were found in the followin rate of preference: PE>PC>PI.

COOPERATION - INSTITUTIONS


  1. Name of institution: Institut fr Biochemie der Technischen Universitaet
    Type of institution: Economical/Production
    City: Graz, Austrija
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