Replacement of dietary fats: Effects on serum lipids and plasma fatty acid composition with special emphasis on the metabolism of essential fatty acids: Dissertation

Research output: ThesisDissertation

Abstract

The effects of fat substitution on plasma fatty acid composition, serum lipid levels and plasma lipid classes were investigated in two studies comprising a total of 100 and 48 subjects, respectively. The analytical methods included gas chromatography (GC) of total plasma and plasma phospholipid (PL) fatty acids, including octadecenoic trans-isomers. A high performance liquid chromatographic method using evaporative light-scattering detection (HPLC-ELSD) was applied for the quantitation of lipid classes. Substitute fats included canola-type, ordinary or cold-pressed rapeseed oils containing ca 11% alfa-linolenic (alfa-LLA) and 23% linoleic (LA) acids, a test margarine, and olive and soybean oils. The average daily doses in the groups during the six-week substitutions, designed to replace butter or margarine on bread, ranged from 14 to 23 g (15-22% of total fat intake). The results demonstrate a preference for n-3 polyunsaturated fatty acid (PUFA) metabolism from alfa-LLA to longer-chain n-3 PUFAs over LA and n-6 PUFA metabolism. This was most completely evident in plasma PL, when butter was replaced by rapeseed oil, as a simultaneous fall in saturated fatty acid (SaFA) and serum LDL cholesterol levels. The effect of monounsaturated oleic acid (n-9 MUFA), the main fatty acid in rapeseed oil (60%), remained neutral showing no increase in PL. The changes in PL followed the order of competition between the unsaturated fatty acid families: (n-3) > (n-6) > (n-9). The increase in n-3 PUFAs was predominant at three weeks, while that in n-6 PUFAs was highest at six weeks, without suppressing n-3 PUFAs. This delay is in line with higher desaturase selectivity for alfa-LLA conversion to long-chain n-3 PUFAs, and with their suppressive effect on n-6 PUFAs. The test margarine (3% alfa-LLA; 28% LA) lacked an n-3 PUFA effect, and an increase in PL LA (n-6) was seen already after the first three weeks. Replacement of margarines by rapeseed oil first reduced both PL SaFAs and n-6 PUFAs, but simultaneously raised n-3 PUFAs and MUFAs. Oleic acid in dietary fat is thus a good counterpart with alfa-LLA. The amount of LA in the diet is in the key position during competition, since the rise in n-6 PUFAs at six weeks suppressed both n-3 PUFAs and MUFAs. Olive oil, instead of raising PUFAs, reduced LA levels in margarine users, which is desirable if the LA intake is high. However, due to the low alfa-LLA (
Original languageEnglish
QualificationDoctor Degree
Awarding Institution
  • University of Helsinki
Supervisors/Advisors
  • Hiltunen, Raimo, Supervisor, External person
  • Laakso, Into, Supervisor, External person
  • Vanhanen, Hannu, Supervisor, External person
  • Viikari, Jorma, Supervisor, External person
Award date20 Jan 2004
Place of PublicationHelsinki
Publisher
Print ISBNs952-10-1069-X
Electronic ISBNs952-10-1070-3
Publication statusPublished - 2004
MoE publication typeG5 Doctoral dissertation (article)

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margarine
essential fatty acids
dietary fat
blood lipids
rapeseed oil
phospholipids
fatty acid composition
metabolism
polyunsaturated fatty acids
fatty acid metabolism
butter
olive oil
omega-3 fatty acids
oleic acid
fat substitutes
average daily intake
omega-6 fatty acids
light scattering
fat intake
lipids

Cite this

@phdthesis{42004e3d0f6a43148723a91b2b775d88,
title = "Replacement of dietary fats: Effects on serum lipids and plasma fatty acid composition with special emphasis on the metabolism of essential fatty acids: Dissertation",
abstract = "The effects of fat substitution on plasma fatty acid composition, serum lipid levels and plasma lipid classes were investigated in two studies comprising a total of 100 and 48 subjects, respectively. The analytical methods included gas chromatography (GC) of total plasma and plasma phospholipid (PL) fatty acids, including octadecenoic trans-isomers. A high performance liquid chromatographic method using evaporative light-scattering detection (HPLC-ELSD) was applied for the quantitation of lipid classes. Substitute fats included canola-type, ordinary or cold-pressed rapeseed oils containing ca 11{\%} alfa-linolenic (alfa-LLA) and 23{\%} linoleic (LA) acids, a test margarine, and olive and soybean oils. The average daily doses in the groups during the six-week substitutions, designed to replace butter or margarine on bread, ranged from 14 to 23 g (15-22{\%} of total fat intake). The results demonstrate a preference for n-3 polyunsaturated fatty acid (PUFA) metabolism from alfa-LLA to longer-chain n-3 PUFAs over LA and n-6 PUFA metabolism. This was most completely evident in plasma PL, when butter was replaced by rapeseed oil, as a simultaneous fall in saturated fatty acid (SaFA) and serum LDL cholesterol levels. The effect of monounsaturated oleic acid (n-9 MUFA), the main fatty acid in rapeseed oil (60{\%}), remained neutral showing no increase in PL. The changes in PL followed the order of competition between the unsaturated fatty acid families: (n-3) > (n-6) > (n-9). The increase in n-3 PUFAs was predominant at three weeks, while that in n-6 PUFAs was highest at six weeks, without suppressing n-3 PUFAs. This delay is in line with higher desaturase selectivity for alfa-LLA conversion to long-chain n-3 PUFAs, and with their suppressive effect on n-6 PUFAs. The test margarine (3{\%} alfa-LLA; 28{\%} LA) lacked an n-3 PUFA effect, and an increase in PL LA (n-6) was seen already after the first three weeks. Replacement of margarines by rapeseed oil first reduced both PL SaFAs and n-6 PUFAs, but simultaneously raised n-3 PUFAs and MUFAs. Oleic acid in dietary fat is thus a good counterpart with alfa-LLA. The amount of LA in the diet is in the key position during competition, since the rise in n-6 PUFAs at six weeks suppressed both n-3 PUFAs and MUFAs. Olive oil, instead of raising PUFAs, reduced LA levels in margarine users, which is desirable if the LA intake is high. However, due to the low alfa-LLA (",
author = "Tuulikki Sepp{\"a}nen-Laakso",
note = "BEL 94 p. + app.",
year = "2004",
language = "English",
isbn = "952-10-1069-X",
series = "Dissertationes Biocentri Viikki Universitatis Helsingiensis",
publisher = "University of Helsinki",
number = "3",
address = "Finland",
school = "University of Helsinki",

}

TY - THES

T1 - Replacement of dietary fats

T2 - Effects on serum lipids and plasma fatty acid composition with special emphasis on the metabolism of essential fatty acids: Dissertation

AU - Seppänen-Laakso, Tuulikki

N1 - BEL 94 p. + app.

PY - 2004

Y1 - 2004

N2 - The effects of fat substitution on plasma fatty acid composition, serum lipid levels and plasma lipid classes were investigated in two studies comprising a total of 100 and 48 subjects, respectively. The analytical methods included gas chromatography (GC) of total plasma and plasma phospholipid (PL) fatty acids, including octadecenoic trans-isomers. A high performance liquid chromatographic method using evaporative light-scattering detection (HPLC-ELSD) was applied for the quantitation of lipid classes. Substitute fats included canola-type, ordinary or cold-pressed rapeseed oils containing ca 11% alfa-linolenic (alfa-LLA) and 23% linoleic (LA) acids, a test margarine, and olive and soybean oils. The average daily doses in the groups during the six-week substitutions, designed to replace butter or margarine on bread, ranged from 14 to 23 g (15-22% of total fat intake). The results demonstrate a preference for n-3 polyunsaturated fatty acid (PUFA) metabolism from alfa-LLA to longer-chain n-3 PUFAs over LA and n-6 PUFA metabolism. This was most completely evident in plasma PL, when butter was replaced by rapeseed oil, as a simultaneous fall in saturated fatty acid (SaFA) and serum LDL cholesterol levels. The effect of monounsaturated oleic acid (n-9 MUFA), the main fatty acid in rapeseed oil (60%), remained neutral showing no increase in PL. The changes in PL followed the order of competition between the unsaturated fatty acid families: (n-3) > (n-6) > (n-9). The increase in n-3 PUFAs was predominant at three weeks, while that in n-6 PUFAs was highest at six weeks, without suppressing n-3 PUFAs. This delay is in line with higher desaturase selectivity for alfa-LLA conversion to long-chain n-3 PUFAs, and with their suppressive effect on n-6 PUFAs. The test margarine (3% alfa-LLA; 28% LA) lacked an n-3 PUFA effect, and an increase in PL LA (n-6) was seen already after the first three weeks. Replacement of margarines by rapeseed oil first reduced both PL SaFAs and n-6 PUFAs, but simultaneously raised n-3 PUFAs and MUFAs. Oleic acid in dietary fat is thus a good counterpart with alfa-LLA. The amount of LA in the diet is in the key position during competition, since the rise in n-6 PUFAs at six weeks suppressed both n-3 PUFAs and MUFAs. Olive oil, instead of raising PUFAs, reduced LA levels in margarine users, which is desirable if the LA intake is high. However, due to the low alfa-LLA (

AB - The effects of fat substitution on plasma fatty acid composition, serum lipid levels and plasma lipid classes were investigated in two studies comprising a total of 100 and 48 subjects, respectively. The analytical methods included gas chromatography (GC) of total plasma and plasma phospholipid (PL) fatty acids, including octadecenoic trans-isomers. A high performance liquid chromatographic method using evaporative light-scattering detection (HPLC-ELSD) was applied for the quantitation of lipid classes. Substitute fats included canola-type, ordinary or cold-pressed rapeseed oils containing ca 11% alfa-linolenic (alfa-LLA) and 23% linoleic (LA) acids, a test margarine, and olive and soybean oils. The average daily doses in the groups during the six-week substitutions, designed to replace butter or margarine on bread, ranged from 14 to 23 g (15-22% of total fat intake). The results demonstrate a preference for n-3 polyunsaturated fatty acid (PUFA) metabolism from alfa-LLA to longer-chain n-3 PUFAs over LA and n-6 PUFA metabolism. This was most completely evident in plasma PL, when butter was replaced by rapeseed oil, as a simultaneous fall in saturated fatty acid (SaFA) and serum LDL cholesterol levels. The effect of monounsaturated oleic acid (n-9 MUFA), the main fatty acid in rapeseed oil (60%), remained neutral showing no increase in PL. The changes in PL followed the order of competition between the unsaturated fatty acid families: (n-3) > (n-6) > (n-9). The increase in n-3 PUFAs was predominant at three weeks, while that in n-6 PUFAs was highest at six weeks, without suppressing n-3 PUFAs. This delay is in line with higher desaturase selectivity for alfa-LLA conversion to long-chain n-3 PUFAs, and with their suppressive effect on n-6 PUFAs. The test margarine (3% alfa-LLA; 28% LA) lacked an n-3 PUFA effect, and an increase in PL LA (n-6) was seen already after the first three weeks. Replacement of margarines by rapeseed oil first reduced both PL SaFAs and n-6 PUFAs, but simultaneously raised n-3 PUFAs and MUFAs. Oleic acid in dietary fat is thus a good counterpart with alfa-LLA. The amount of LA in the diet is in the key position during competition, since the rise in n-6 PUFAs at six weeks suppressed both n-3 PUFAs and MUFAs. Olive oil, instead of raising PUFAs, reduced LA levels in margarine users, which is desirable if the LA intake is high. However, due to the low alfa-LLA (

M3 - Dissertation

SN - 952-10-1069-X

T3 - Dissertationes Biocentri Viikki Universitatis Helsingiensis

PB - University of Helsinki

CY - Helsinki

ER -