Summary of the Report of the Ad Hoc Committee on the Composition of Special Margarines The Ad Huc Committee on the Composition of Special Margarines was asked to consider and make recommenda- tions on the following questions: (I) Is there a need for special margarines having declared fatty acid characteristics? (2) How should the presence of Irons fatty acids in mar- garines be considered with respect to saturated fatty acids? (3) In consideration of the Committee's response to ques- tion number 2 and the best interests of consumers, should label declarations for margarines (as permitted under the Food and Drug Regulations) take into account the presence of lrans fatty acids? (4) Should the minimum level of eis-methylene interrupted polyunsaturated fatty acids, as specified in current regulations, be replaced by a minimum level of the equivalent amount of linoleic acid? The Committee finds that there is a need for specially labelled margarines and other vegetable oil products rich in linoleic acids in the diet of the general public since they tend to lower serum lipids and should help to reduce the risk from ischemic vascular disease. Specially labelled margarines are essential in the preparation of therapeutic diets, for the treat- ment of patients with very high serum lipid levels and a very high risk of heart disease. The Committee has reviewed the scientific literature concerning Irons fatty acid and heard testimony from seven expert witnesses. In vilro studies have shown that Irons acids are a fatty-acid class with unique characteristics. Studies of activation, oxidation, esterificiation to phospholipids and cholesterol, and of the physical properties of Irans-acid- containing complex lipids have all demonstrated these unique characteristics. In general, these properties tend to more closely resemble the saturated fatty acids than the corresponding eis-unsaturated isomers. Animal studies have shown that Irons fatty acids have no essential fatty acid properties and can actually exaggerate the signs and symptoms of essential fatty acid deficiency. They are hypercholesterolemic in rabbits in the presence, but not in the absence, of dietary cholesterol, and have atherogeni- city similar to saturated fatty acids. Atherogenicity in swine was no different from that observed in a control group fed a basal diet. Trans. Irons-octadecadienoic acids, when in excess of linoleic acid, can cause an increase in kidney weight, liver lipid levels, and decrease the arachidonic acid content of liver lipids. Trans acids are readily absorbed from the diet, and their incorporation into complex lipids seems to be a function of several variables such as animal species, tissue, and nature of the acceptor lipid. Whether the tissue and lipid class selectivity for Irons acids has any physiologi- cal significance has not been resolved. They are readily metabolized by most tissues. Long-term feeding studies have indicated no change in the growth, reproduction or longevity of animals fed hydrogenated fats with various levels of Irons fatty acids. Studies of Irons fatty acid metabolism in man have shown that lrans acids are handled similarly in man as in experi- mental animals, and that the human enzyme systems responsible for maintaining the fatty acid profile of complex lipids are sensitive to the Irons double bond and the physical properties of the fatty acid moiety. There is insufficient evidence to implicate Irons fatty acids in a particular role in human cancer. Whether they elevate plasma lipid levels in man is not certain; studies where Irons. Irans-dienes were a significant component of the diet were generally associated 90/ Affaires de l'lnstitut with elevated serum lipid levels. Where Iran.l'-monoenes were the only lipid variable, hypercholesterolaemia was observed in two related studies, and no significant change in another independent study. The reason(s) for these discrepant results is unknown. The Committee noted that some of the effects of Irons fatty acids were apparent only when there was limited avail- ability of the essential fatty acid, linoleic acid [18:2 (n-6)]. This fatty acid is the major essential fatty acid in the diet. It lowers serum lipids and is potentially antiatherogenic, and is a platelet antiaggregating agent and hence potentially antithrombogenic. Other properties which have been reported and which warrant further attention include an antihypertensive action, improved myocardial function, and the normalization of insulin metabolism in some forms of diabetes. Although linolenic acid [18:3 (n-3)] and its deriva- tives share to a limited extent the lipid-lowering and anti- thrombogenic properties of linoleic acid, they have little essential fatty acid activity and may, in fact, interfere in some normal aspects of linoleic acid metabolism. Accordingly, the Committee has recommended that a linoleic acid standard be adopted for specially labelled margarines and other vegetable oil products. The Committee noted the rapidity of recent change in the understanding of the pharmacology and metabolism of poly- unsaturated fatty acids and their derivatives such as prostaglandins, prostacyclins, throm boxanes, and leuko- trienes. Some of the newer findings are preliminary and occasionally controversial, and further research is required. Accordingly, it is essential that those individuals and organi- zations concerned with dietary recommendations be con- tinuously and critically aware of future developments in this field. Because both professionals and the general public expect that vegetable oil products will contain polyunsaturated fatty acids that are desirable dietary components, and since the most desirable of these acids by far is linoleic, the Com- mittee was very concerned to note that several samples of margarines marketed in Canada contained less than 5% lino- leic acid. In some cases, these products also contained high levels of Irons acids. To aid in achieving the linoleic acid intake recommended by the Canadian Dietary Standard (2% of calories), and in counteracting the less desirable pro- pertii::s of saturated and Irons acids, we strongly recommend that all margarines and margarine-like products should be subject to regulations requiring a minimum content of lino- leic acid [ds. cis 18:2 (n-6)]. The Committee suggests a level of 5% to permit a contribution to the daily linoleate intake, and yet not so high as to create undue problems with respect to cost and supply. We would urge the Bureau and industry to consult together to establish a minimum level compatible with an adequate linoleate intake, reasonable cost to the consumer, and present and projected oil supplies. Since Irons, Irons-I 8:2 has been associated with elevated serum lipid levels, and with changes in organ weight, lipid content, and decreased arachidonic acid content, when levels approximate or exceed those of linoleic acid, and since these Irons acids can be virtually eliminated by good hydrogena- tion practices, we recommend a general regulation limiting the Irons. Irons-I 8:2 content of all margarines, shortenings, and shortening-like products to less than 1%. There is abundant evidence that Irons fatty acids have a unique metabolism in vilro and in vivo. in experimental animals and man. They are not the same as the eis-isomers, but resemble more closely saturated fatty acids. Trans. Irans- 18:2 excepted, and with adeq uate linoleate intake, there is no strong evidence that they are any more harmful than any other fatty acid class. However, some animal and human studies indicate they may elevate serum lipids. These obser- J.lnst. Can. Technol. AlimenJ. Vcl. 14. No. 2, Avril1981
Transcript
Summary of the Report of theAd Hoc Committee on theComposition of Special Margarines
The Ad Huc Committee on the Composition of SpecialMargarines was asked to consider and make recommendations on the following questions:(I) Is there a need for special margarines having declared
fatty acid characteristics?(2) How should the presence of Irons fatty acids in mar
garines be considered with respect to saturated fattyacids?
(3) In consideration of the Committee's response to question number 2 and the best interests of consumers,should label declarations for margarines (as permittedunder the Food and Drug Regulations) take intoaccount the presence of lrans fatty acids?
(4) Should the minimum level of eis-methylene interruptedpolyunsaturated fatty acids, as specified in currentregulations, be replaced by a minimum level of theequivalent amount of linoleic acid?
The Committee finds that there is a need for speciallylabelled margarines and other vegetable oil products rich inlinoleic acids in the diet of the general public since they tendto lower serum lipids and should help to reduce the risk fromischemic vascular disease. Specially labelled margarines areessential in the preparation of therapeutic diets, for the treatment of patients with very high serum lipid levels and a veryhigh risk of heart disease.
The Committee has reviewed the scientific literatureconcerning Irons fatty acid and heard testimony from sevenexpert witnesses. In vilro studies have shown that Irons acidsare a fatty-acid class with unique characteristics. Studies ofactivation, oxidation, esterificiation to phospholipids andcholesterol, and of the physical properties of Irans-acidcontaining complex lipids have all demonstrated theseunique characteristics. In general, these properties tend tomore closely resemble the saturated fatty acids than thecorresponding eis-unsaturated isomers.
Animal studies have shown that Irons fatty acids have noessential fatty acid properties and can actually exaggerate thesigns and symptoms of essential fatty acid deficiency. Theyare hypercholesterolemic in rabbits in the presence, but notin the absence, of dietary cholesterol, and have atherogenicity similar to saturated fatty acids. Atherogenicity in swinewas no different from that observed in a control group fed abasal diet. Trans. Irons-octadecadienoic acids, when inexcess of linoleic acid, can cause an increase in kidneyweight, liver lipid levels, and decrease the arachidonic acidcontent of liver lipids. Trans acids are readily absorbed fromthe diet, and their incorporation into complex lipids seems tobe a function of several variables such as animal species,tissue, and nature of the acceptor lipid. Whether the tissueand lipid class selectivity for Irons acids has any physiological significance has not been resolved. They are readilymetabolized by most tissues. Long-term feeding studies haveindicated no change in the growth, reproduction or longevityof animals fed hydrogenated fats with various levels of Ironsfatty acids.
Studies of Irons fatty acid metabolism in man have shownthat lrans acids are handled similarly in man as in experimental animals, and that the human enzyme systemsresponsible for maintaining the fatty acid profile of complexlipids are sensitive to the Irons double bond and the physicalproperties of the fatty acid moiety. There is insufficientevidence to implicate Irons fatty acids in a particular role inhuman cancer. Whether they elevate plasma lipid levels inman is not certain; studies where Irons. Irans-dienes were asignificant component of the diet were generally associated
90/ Affaires de l'lnstitut
with elevated serum lipid levels. Where Iran.l'-monoenes werethe only lipid variable, hypercholesterolaemia was observedin two related studies, and no significant change in anotherindependent study. The reason(s) for these discrepant resultsis unknown.
The Committee noted that some of the effects of Ironsfatty acids were apparent only when there was limited availability of the essential fatty acid, linoleic acid [18:2 (n-6)].This fatty acid is the major essential fatty acid in the diet. Itlowers serum lipids and is potentially antiatherogenic, and isa platelet antiaggregating agent and hence potentiallyantithrombogenic. Other properties which have beenreported and which warrant further attention include anantihypertensive action, improved myocardial function, andthe normalization of insulin metabolism in some forms ofdiabetes. Although linolenic acid [18:3 (n-3)] and its derivatives share to a limited extent the lipid-lowering and antithrombogenic properties of linoleic acid, they have littleessential fatty acid activity and may, in fact, interfere in somenormal aspects of linoleic acid metabolism. Accordingly, theCommittee has recommended that a linoleic acid standard beadopted for specially labelled margarines and othervegetable oil products.
The Committee noted the rapidity of recent change in theunderstanding of the pharmacology and metabolism of polyunsaturated fatty acids and their derivatives such asprostagland ins, prostacyclins, throm boxanes, and leukotrienes. Some of the newer findings are preliminary andoccasionally controversial, and further research is required.Accordingly, it is essential that those individuals and organizations concerned with dietary recommendations be continuously and critically aware of future developments in thisfield.
Because both professionals and the general public expectthat vegetable oil products will contain polyunsaturatedfatty acids that are desirable dietary components, and sincethe most desirable of these acids by far is linoleic, the Committee was very concerned to note that several samples ofmargarines marketed in Canada contained less than 5% linoleic acid. In some cases, these products also contained highlevels of Irons acids. To aid in achieving the linoleic acidintake recommended by the Canadian Dietary Standard(2% of calories), and in counteracting the less desirable propertii::s of saturated and Irons acids, we strongly recommendthat all margarines and margarine-like products should besubject to regulations requiring a minimum content of linoleic acid [ds. cis 18:2 (n-6)]. The Committee suggests a levelof 5% to permit a contribution to the daily linoleate intake,and yet not so high as to create undue problems with respectto cost and supply. We would urge the Bureau and industryto consult together to establish a minimum level compatiblewith an adequate linoleate intake, reasonable cost to theconsumer, and present and projected oil supplies.
Since Irons, Irons-I 8:2 has been associated with elevatedserum lipid levels, and with changes in organ weight, lipidcontent, and decreased arachidonic acid content, when levelsapproximate or exceed those of linoleic acid, and since theseIrons acids can be virtually eliminated by good hydrogenation practices, we recommend a general regulation limitingthe Irons. Irons-I 8:2 content of all margarines, shortenings,and shortening-like products to less than 1%.
There is abundant evidence that Irons fatty acids have aunique metabolism in vilro and in vivo. in experimentalanimals and man. They are not the same as the eis-isomers,but resemble more closely saturated fatty acids. Trans. Irans18:2 excepted, and with adeq uate linoleate intake, there is nostrong evidence that they are any more harmful than anyother fatty acid class. However, some animal and humanstudies indicate they may elevate serum lipids. These obser-
vations, coupled with the desirability of having as muchlinoleic acid in the product as possible, have led us torecommend that for special margarines, the content ofsaturated plus trans acids should not exceed 40%.
The Committee encountered many areas of uncertaintywith respect to knowledge of the metabolism of Irons acidsand of polyunsaturated fatty acids and their derivatives. Westrongly recommend further research in this field, supportedby government, industry and universities.
It should be noted that low levels of trans fatty acids havebeen a natural component of man's diet for centuries. However, use of hydrogenated fats and oils have increased hisintake appreciably over the past decade. Industry and regulatory agencies should work closely together to ensure themanufacture of products that do not exaggerate this intake.The Committee finds it unacceptable that with current technology in food processing there are hydrogenated vegetableoil products marketed in Canada which have extremely lowlevels of essential fatty acids and high levels of Irons fattyacid. It expects that industry will rapidly alter this situationand that margarines and margarine-like products will easilyexceed the minimum standards in the usual monitoring overthe next five years. Finally, because periodic review andupdating of policies and procedures is essential for a sorapidly changing segment of the Canadian food supply, theCommittee recommends a review of research and industrialadvances similar to this one in approximately five years time.
Recommendations(I) There is a need for margarines, shortenings and salad oils
having declared fatty acid characteristics. These products are desirable for persons wanting to lower serumlipids as a means of reducing the risk of ischemic vasculardisease from atherosclerotic complications. They aredesirable also as a means of ensuring an adequate intakeof the essential fatty acid, linoleic acid.
(2) The appropriate sections of the Food and Drug Regulations should be amended for special margarines, saladoils and dressings of appropriate characteristics. Labelling claims should be permitted when the proportion ofeis. cis linoleic acid [18:2 (n-6)] contained in the total fatis at least 40% in the case ofan oil, and at least 25% in thecase of a shortening, margarine or a margarine-likeproduct. The proportion of saturated fatty acid shouldnot exceed 25%, and saturated plus lrans fatty acidshould not exceed 40%. The label of such a productshould state the proportion of linoleic acid on a total fatbasis. Since linoleic acid may not be a generallyrecognized term, the use of an explanatory statement, inbrackets, such as (the major PU FA) or (the major polyunsaturated fatty acid) should be encouraged.
(3) As noted in (2) above; the standard for polyunsaturatedfatty acids for margarines, shortenings, and margarinelike products should be eis, cis linoleic acid [18:2 (n-6)]rather than eis, cis methylene interrupted polyunsaturated fatty acids.
(4) There should be a general regulation(a) for all margarines, shortenings and margarine-like
products requiring less than 1% trans, transoctadecadienoic acid;
(b) for all margarine and margarine-like productsrequiring a minimum of 5% linoleic acid.
(5) Industry should be encouraged to seek ways to increasethe linoleate content while reducing the trans fatty acidcontent of Canadian foods.
(6) Further research should be supported by government,universities and industry. Important areas requiringfurther study include:
(a) the effects of Irons fatty acids on serum lipids in man;(b) the effects of Irons fatty acids on the physiology and
biochemistry of vital organs such as heart, kidney,tes tis and brain;
(c) the effects of individual fatty acid isomers in biological systems;
(d) improvements in the processing of fats and oils toconserve the linoleic acid;
(e) the biological roles of polyunsaturated fatty acidsand their derivatives.
(7) The Bureau of Nutritional Sciences should remain awareof continuing developments in the biology of polyunsaturated fatty acids and of Irons fatty acids, and conductor sponsor a major review of the area in 5 years. Throughout this period, the fatty acid composition of Canadianretail oil foods should be determined at periodic intervals, and the results and trends assessed at the 5 yearre-examination. Industry should be made aware of thisintent at the outset.
Committee MembershipDr. Jean Davignon, Institut de Recherches Cliniques de
Montreal.Dr. Bruce Holub, Department of Nutrition, University of
Guelph.Dr. J. Alick Little, Department of Medicine, University of
Toronto.Dr. Bruce E. McDonald, Department of Food and Nutri
tion, Faculty of Home Economics, University ofManitoba.
Dr. Matthew Spence, Department of Pediatrics, DalhousieUniversity (Chairman).
Expert WitnessesDr. R.L. Anderson, The Procter and Gamble Co., Miami
Valley Laboratories, Cincinnati, Ohio.Dr. Joyce Beare-Rogers, Bureau of Nutritional Sciences,
Health and Welfare Canada, Ottawa.Mr. D.G. Caldwell, Executive Director, The Institute of
Edible Oil Foods, Toronto.Dr. Margaret Cheney, Bureau of Nutritional Sciences,
Health and Welfare Canada, Ottawa.Dr. J.J. Gottenbos, Unilever Research Laboratory,
Vlaardingen, Holland.Dr. G..D. Micklea, Chairman, Technical Committee, The
Institute of Edible Oil Foods, Toronto.Dr. Leon Rubin, Department of Chemical Engineering,
University of Toronto.
GlossaryFally Acids
The basic chemical nomenclature is based on the hydrocarbon chain.
NumberinK SystemUsed to indicate chain length, degree of unsaturation and
position of the double bond. For example, in 18:1 (n-9), 18indicates the number of carbon atoms, the one to the right ofthe colon indicates the number of double bonds, and thenumber in brackets (n-9), the position of the double bond,measured from the methyl end. Double bond position canalso be indicated by w (omega), e.g.,
n-9 = w9n-6 = w6n-3 = w3
Double-bond pOSitIOn from the carboxyl end is usuallysignified by a t:, nomenclature, often used when describingenzymes that insert double bonds in the saturated fatty acidprecursors, e.g., t:,6-desaturase inserts a bond 6 carbons fromthe carboxyl end.
e 18:1 (n-9)c 18: 1 (n-7)I 18:1 (n-9)c 18:1 (n-12)
cc 18:2 (n-6)I I 18:2 (n-6)
18:3 (n-6)18:3 (n-3)20:4 (n-6)
Geometric Isomers(eis, trans, abbrev. e,t) Cis isomers have two similar
groups on the same side of the double bond (e.g., oleic acid);consequently, the bond has an angle. Trans isomers have twosimilar groups on opposite sides of the double bond; thebond angle is more than the eis bond (e.g., elaidic acid).H-C-(CH2kCH 3 CH 3-(CH 2h-CH
11 11H-C-(CH 2)?-COOH HC-(CH2h-COOH
eis-oleic acid trans-elaidic acid
Positional IsomersFatty acids of similar chain length and number of double
bond(s), but the position of the double bonds in the hydrocarbon chain varies [e.g., e-18: I (n-9), oleic acid and e-18: I(n-II), eis-vaccenic acid]. Conjugated dienes (e.g., eis,eis-9, I I-octadecadienoic acid) are positional isomers of themore usual dienes (e.g., eis, eis-9,12-octadecadienoic acid).The double bonds are separated by two carbons in theformer, and three carbons (methylene-interrupted) in thelatter.
The trivial name, systematic name, and shorthandnumbering system for many of the fatty acids discussed inthis report are listed in Table I.
Editorial Note: The preceding summary was provided byHealth and Welfare Canada. The full report can be obtainedby contacting Jean Sattar, Health and Welfare Canada,(613) 996-0446.
F.R.V.
Canadian Fish Supplies to the German MarketCanada became the world's number one fish exporter in
1978 and European importers and processors should begearing up now to take advantage of Canada's continuity ofsupply, reasonable prices and a vailability, which are assuredby a well managed bounty.
Canada sees itself as only one of the countries thatbenefited from the new 200-mile economic zones and itsfishing industry is concentrating now on preparing to givesuperior value to countries such as Germany which increasingly buys our fish and seafood products.
Canadian catch forecasts are good news for German fishbuyers. For 198 I and 1985 Canada foresees large increases inmost stocks except for herring, freshwater fish, scallops,halibut and haddock, but even these species are expected tohold at their present supply levels.
Presented below are the maximum availability forecastsrelative to actual Canadian landings of major species in 1977(thousands of metric tons round weight):
Source: Department of Fisheries and Oceans, Ottawa, 1979.
The main species Canada has exported to Germany havebeen herring, cod, salmon, snow crab and lobster, andCanadian exporters hope to increase their sales to Germanyof these species and open up exports of other species nowbecause of changes in market preferences or supply patterns.These imports are processed in Germany not only for theirdomestic market but for export to EC countries, Switzerland, Austria and Sweden, providing a large value-addedfactor which guarantees many jobs in Germany.
Canada already supplies 56% of Germany's frozenherring imports (55,637 tonnes in 1977) and about the samepercentage of barrelled herring. Of Germany's salmonimports, 40% are from Canada. Canada also supplies codand other groundfish, lobster, eels and freshwater fish.
While Canadians eat only 7.9 kilos of fish per person,Germans eat 9.1 kg - both far below the 65 kg eaten by eachperson in Japan. Canada is undertaking greatly increaseddomestic market promotion of fish with a view to increasingthe amount of fish eaten. A similar development in Germanywould benefit both Canadian imports and German processors.
Inherent in such marketing success are reasonable prices.Canadian prices are already competitive and the Canadianfishing industry has undertaken energy conservationschemes to cut the effects of increased energy costs on theprice of its fish exports. They have achieved almost a 15%saving over the past 2 years and are aiming at another 15%over the next 5 or 6 years.
J. Ins'. Can. Technol. Aliment. Vol. 14. No. 2. Avri1198!
