82
Gamma Linolenic Acid (GLA) Content of Encapsulated Evening Primrose Oil Products Robert A. Gibson*, David R. Lines and Mark A. Neumann Department of Pediatrics and Child Health, Flinders Medical Centre, Bedford Park (Adelaide) 5042, Australia
The fatty acid composition of 16 brands of evening primrose oil (EPO) capsules was determined by capillary gas chromatography. Fourteen of these EPO brands contained y-linolenic acid (GLA) levels between 7% and 10% (mean, 8.7; range, 1.9-10.5%) and there was generally good agreement between the level of GLA claimed by the manufacturer and the level determined by analysis. Low levels of the monoenes 22:1 and 24:1 found in some brands may indicate contamination of EPO with borage oil. Lipids 27, 82-84 (1992). There is evidence that, in humans, either the conversion of linoleic acid (LA, 18:2n-6) to 7-1inolenic acid (GLA, 18:3n-6) is blocked or the A6 desaturase responsible for the conversion is fully saturated. In either event, levels of GLA and other metabolites, including dihomo-),-linolenic acid (DGLA, 20:3n-6) and arachidonic acid (AA, 20:4n-6), are unaffected by dietary supplementation with LA rich oils, but are elevated by consumption of evening primrose oil (EPO) which contains on average 9% GLA (1). A number of clinical conditions have been treated orally with EPO, including pre-menstrual tension (2), rheumatoid arthritis (3) and breast disorders (4). Atopic eczema in children and adults is the condition showing the best result from oral EPO treatment (5). Based on a number of such studies (6), a product license has been granted to at least one pharmaceutical company under the label "Epogam" for the treatment of eczema. In many countries, including Australia, numerous EPO brands are available in pharmacies and health food stores. We report here a systematic study on the fatty acids of a range of EPO products which we measured using sensitive capillary column gas chromatography.
MATERIALS AND METHODS EPO capsules were obtained from pharmacies and health food stores in Sydney, Melbourne and Adelaide and, where possible, more than one batch number of each product was purchased. All capsules tested were in the soft gelatin form. The retail cost varied and ranged from AS 0.19 to AS 0.52 per capsule. All EPO samples were tested against a standard that had been extracted from evening primrose seed in our laboratory. Seeds (5 g) were homogenized in 30 mL of petroleum hydrocarbon and the homogenate centrifuged. The supernatant was decanted and the sediment extracted twice with 30-mL washes of petroleum hydrocarbon. The combined supernatants were filtered and the solvent *To whom correspondenceshould be addressed. Abbreviations: EPO, evening primrose oil; GLA, ),-linoleulc acid (18:3n-6); LA, linoleicacid (18:2n-6);MUFA, monounsaturatedfatty acids; SFA, saturated fatty acids; TLC, thin-layerchromatography. LIPIDS, Vol. 27, no. 1 (1992)
evaporated. Thin-layer chromatography (TLC) revealed that only triglycerides were present. Fatty acid analysis. TLC showed that all commercial products were predominantly in the triglyceride form. EPO was removed from capsules and 1-2 ~L added to glass vials without further purification. Five mL of a solution of 1% H2SO4 in methanol was added to each vial. Vials were sealed and heated at 70~ for 3 hr. After cooling, the resulting methyl esters were extracted with 2 mL n-heptane. The extract was transferred into 2-mL auto sampler vials containing anhydrous sodium sulfate. Fatty acid methyl esters were separated on a wide bore (0.56 ram) 50-m capillary column coated with SP 2340 (Supelco Inc, Bellefonte~ PA) using a Hewlett Packard 5880 gas chromatograph (Hewlett Packard, Palo Alto, CA). Chromatographic conditions were those described in detail elsewhere (7). Helium was used as the carrier gas at a flow of 30 cm/sec. The oven temperature was increased from 120~ to 200~ at 5~ per min; injection temperature was held at 250 ~ and flame ionization detector temperature was 300~ Samples (1 ~L) were injected using the split mode at a 30:1 ratio. Variation. All products were sampled in triplicate. Variation in major peaks was less than 5%, while the variation in minor peaks (20%) of saturates measured in Nature's Own Plus are due to oils present in an added vitamin/mineral mix. Examination of the minor components of the products showed interesting differences between brands. Several brands contained detectable amounts of C22 and C24 monounsaturated fatty acids (MUFA), which were not found in our laboratory standard EPO. While it is possible that these low levels of C22 and C24 MUFA are due to genetic differences among the various strains of evening primrose, we consider this unlikely. Analysis of oil extracted in our laboratory from seeds of evening primrose strains from Europe, China, Australia, New Zealand and North America has failed to reveal the presence of these MUFA.
83 COMMUNICATION TABLE 1
Fatty Acid Compositiona of Different Brands of Evening Primrose Oil Capsules Brand b
B a t c h no.
Label GLA c
GLA
LA
Total SFA d
Total MUFA e
20:1n-9
22:1n-ll
24:1n-9
10 10 10 8 8 8 8 8 8 8 8 10 10 10 10 10 10 10 10 10 10 8 8 8 7.9 7.9 7.9 7.9 9-10 10 10 10 8 10
9.8 9.6 9.2 9.5 8.2 8.2 9.0 8.0 7.6 8.6 8.0 10.1 10.1 9.1 10.4 10.0 9.8 8.8 10.0 10.0 9.0 9.3 8.2 6.3 7.6 7.7 7.4 7.1 10.5 10.5 9.6 9.5 7.6 9.1
72.2 71.2 71.4 71.9 71.1 73.9 69.4 73.1 71.2 74.1 74.3 65.5 65.5 65.5 65.3 65.9 63.5 69.9 63.2 65.5 65.3 74.3 74.7 67.7 59.7 60.1 64.5 63.0 64.0 64.0 72.6 73.3 74.1 64.9
8.5 8.9 9.4 8.4 8.1 8.8 8.5 8.9 8.1 8.3 8.8 9.2 9.2 9.3 9.0 8.8 9.7 9.6 9.2 8.9 9.4 8.4 8.3 10.4 24.2 23.8 26.2 26.3 9.2 9.2 8.5 9.2 8.9 9.6
9.3 10.2 9.8 10.1 12.4 8.9 11.8 9.9 13.1 8.9 8.9 15.2 15.2 16.1 15.5 15.3 16.9 11.6 16.2 15.5 16.4 7.9 8.7 15.3 8.1 8.0 9.9 11.1 16.3 16.2 9.1 7.6 9.3 16.4
0.13 0.21 0.18 0.12 0.13 0.16 0.31 0.13 0.14 0.15 0.16 0.84 0.83 0.80 0.84 0.74 1.00 0.64 0.88 0.80 0.81 0.14 0.15 0.21 0.12 0.12 0.16 0.16 0.95 0.91 0.14 0.15 0.16 0.89
------0.84 ----0.47 0.47 0.46 0.45 0.42 0.60 0.30 0.52 0.45 0.47 --0.09 ----0.53 0.53 ---0.49
-----------0.26 0.26 0.24 0.25 0.22 0.33 0.18 0.29 0.24 0.26 -------0.31 0.30
Soul P a t t i n s o n N a t u r a l Care
30924 30130 30927 30234 23038 23634 24253 29317 22994 23600 23749 A0233 A0139 30305 90835 00422 2900 1039 M9830 E0974 M0093 5987B 3261-2 3064 32315 32315 3399A 34941 07 08 33915 34562 56727 16969
Amcal MicroGenics Moonkist EPO
36439 8481 190
8 10 5.2
8.2 9.7 1.9
74.6 70.0 75.8
8.4 9.4 13.7
8.7 10.8 8.6
0.14 0.58 0.15
-0.28 --
-0.17 --
Naudicelle
Efamol
Eviprim Blackmores
Natural Nutrition
Healtheries
Nature's Own
Bioglan
Nature's Own Plus
Good Health Macro
--0.28
a V a l u e s are m e a n s g i v e n as % w e i g h t of t o t a l f a t t y acids. b T h e following p r o d u c t s were s a m p l e d : Nandicelle (Key P h a r m a c e u t i c a l s P t y . L t d . R h o d e s , N.S.W. Australia}; E f a m o l (Efamol, L o n d o n , England}; E v i p r i m {Key P h a r m a c e u t i c a l s Pty. Ltd.}; B l a c k m o r e s B o t a n i c a l s ( B l a c k m o r e s Ltd. B a l g o w l a h , N.S.W. Australia}; N a t u r a l Nutrition, N a t u r e ' s O w n a n d N a t u r e ' s O w n P l u s (Natural H e a l t h P r o d u c t s Pty. Ltd., Kippa-Ring, Q.L.D. Australia); Healtheries (Healtheries of N e w Zealand, A u c k l a n d , N e w Zealand}; B i o g l a n [Bioglan L a b o r a t o r i e s {Aust.) Pty. Ltd., MarrickviUe, N.S.W. Australia]; Good H e a l t h {Good H e a l t h P r o d u c t s , A u c k l a n d , N e w Zealand); M a c r o (Lederle L a b o r a t o r i e s Division, C y a n a m i d A u s t r a l i a Pty. Ltd., B a u l k h a m Hills, N.S.W. Australia}; Soul P a t t i n s o n [Soul P a t t i n s o n {Laboratories) P t y . Ltd., K i n g s g r o v e , N.S.W. A u s t r a l i a ] ; N a t u r a l Care A u s t r a l i a , B r u n s w i c k H e a d s , N.S.W. Australia}; A m c a l {Allied M a s t e r C h e m i s t s of A u s t r a l i a L i m i t e d , S p r i n g v a l e , V.I.C. Australia); Micro Genics {Twin L a b s Pty. Ltd., W i n d s o r , V.I.C. Australia}; M o o n k i s t {Gum P a r k Pty. Ltd., C a n n a w i g a r a S.A. Australia}. c % A s listed b y m a n u f a c t u r e r . d I n c l u d e s 14:0, 15:0, 16:0, 17:0, 18:0, 20:0, 22:0 a n d 24:0. e I n c l u d e s 14:1, 15:1, 16:1, 17:1, 18:1, 20:1, 22:1 a n d 24:1.
TABLE 2 Fatty Acid Compositiona of EPO, Borage and Safflower Oils
EPO Borage E P O / B o r a g e (84:16) B o r a g e / S a f f l o w e r (60:40)
GLA 18:3n-6
LA 18:2n-6
Total SFA b
Total MUFA c
20:1n-9
22:1n-ll
24:1n-9
7.0 26.1 9.8 9.8
69.7 38.1 64.9 60.9
8.2 12.6 8.8 10.8
15.0 22.8 16.4 18.3
0.24 4.31 0.79 1.94
-2.70 0.46 1.27
-1.56 0.25 0.90
a V a l u e s are m e a n s g i v e n as % w e i g h t of t o t a l f a t t y acids, 15:1, 16:1, 17:1, 18:1, 20:1, 22:1, a n d 24:1.
b I n c l u d e s 14:0, 15:0, 16:0, 17:0, 18:0, 20:0, 22:0 a n d 24:0.
c I n c l u d e s 14:1,
LIPIDS, Vol. 27, no. 1 (1992)
84
COMMUNICATION We investigated the possibility t h a t some of the capsules contained blends of E P O and either borage or safflower oil (Table 2). Starting with an E P O sample with 7% GLA, blends of oils were prepared which were designed to achieve a G L A level of 10%. The f a t t y acid profile of the EPO/Borage oil blend (84:16) more closely m a t c h e d the profile seen in some of the capsules t h a n the Borage]Safflower blend 160:40). G L A is the claimed active ingredient of E P O and, thus, consumers and researchers alike are interested in the G L A content of E P O products. Although the levels of G L A in the products tested in this s t u d y were in the range expected for EPO, minor constituents in some products suggested t h a t some m a y contain contaminants of other oils. Unlike marine oils t8), E P O is relatively easy to analyze (particularly by capillary gas chromatography) as it contains only two major polyunsaturated f a t t y acids {LA and GLA), and sometimes low levels of a-linolenic acid (18:3n-3) E P O is devoid of C22 and C24 MUFA t h a t are present in some other GLA-containing oils, such as borage (9). Despite this, several of the products t h a t we tested were found to contain a m o u n t s of 20:1, 22:1 and 24:1 consistent with a blend of borage and E P O {Table 2). I t is interesting t h a t m o s t of the capsules t h o u g h t to contain EPO/borage blends also contained G L A levels close to 10% of the total f a t t y acids. W h e t h e r this represents an a t t e m p t by manufacturers to supply oils with a s t a n d a r d G L A content or is the result of accidental contamination during pressing and/or extraction is unknown.
LIPIDS, Vol. 27, no. 1 (1992)
There are no reports of the c o m p a r a t i v e physiological or clinical effects of the various G L A containing oils in humans. Until this is done, the significance of capsules of E P O containing low levels of borage or other oils remains largely one of labelling.
REFERENCES 1. Gibson, R.A., and Rassias, G. (1990) in Omega-6 Essential Fatty Acids: Pathophysiology and Roles in Clinical Medicine (Horrobin, D., ed.) pp. 283-293, Alan R. Liss, New York. 2. Ockermarm, RA., Backrack, I., Glans, S., and Rassner, S. 11986) Rec. Adv. Clin. Nutr. 2, 404-405. 3. Belch, J.J.F., Ansell, D., Madhock, R., O'Dowd, A., and Sturrock, R.D. 11988)Am. Rheum. Dis. 47, 96-100. 4. Mansel, R.E., Py~ J.K., and Hughes, L.E. 11990)in Omega~ Essential Fatty Acids: Pathophysiology and Roles in Clinical Medicine
(Horrobin, D., ed.) pp. 557-566, Alan R. Liss, New York. 5. Wright, S., and Burton, J.L. 11982) Lancet ii, 1120-1125. 6. Morse, RE., Horrobin, D.E, Manku, M.S., Stewart, J.C.M., Allen, R., Littlewood, S., Wright, S., Burton, J., Gould, D.J., Holt, P.J., Jansen, C.T.,Mattila, L., Meigel, W., Dettke, T.H., Wexler, D., Guenther, L., Bordoni, A., and Patrizi, A. 11989) Br. J. Dermatol. 121, 75-90. 7. James, M.J., Cleland, L.G., Gibson, R.A., and Hawkes, J.S. 11991) J. Nutr. 121, 631-637. 8. Ackman, R.G. 11987)Acta Meal Scand 222, 99-105. 9. Muderhwa, J.M., Dhuique-Mayer, C., Pina, M., Galzy, E, Grignae, P., and Graille, J. 11987) Oleagineux 42, 207-211. [Received July 26, 1991; Revision accepted October 4, 1991]
Gamma Linolenic Acid (GLA) Content of Encapsulated Evening Primrose Oil Products Robert A. Gibson*, David R. Lines and Mark A. Neumann Department of Pediatrics and Child Health, Flinders Medical Centre, Bedford Park (Adelaide) 5042, Australia
The fatty acid composition of 16 brands of evening primrose oil (EPO) capsules was determined by capillary gas chromatography. Fourteen of these EPO brands contained y-linolenic acid (GLA) levels between 7% and 10% (mean, 8.7; range, 1.9-10.5%) and there was generally good agreement between the level of GLA claimed by the manufacturer and the level determined by analysis. Low levels of the monoenes 22:1 and 24:1 found in some brands may indicate contamination of EPO with borage oil. Lipids 27, 82-84 (1992). There is evidence that, in humans, either the conversion of linoleic acid (LA, 18:2n-6) to 7-1inolenic acid (GLA, 18:3n-6) is blocked or the A6 desaturase responsible for the conversion is fully saturated. In either event, levels of GLA and other metabolites, including dihomo-),-linolenic acid (DGLA, 20:3n-6) and arachidonic acid (AA, 20:4n-6), are unaffected by dietary supplementation with LA rich oils, but are elevated by consumption of evening primrose oil (EPO) which contains on average 9% GLA (1). A number of clinical conditions have been treated orally with EPO, including pre-menstrual tension (2), rheumatoid arthritis (3) and breast disorders (4). Atopic eczema in children and adults is the condition showing the best result from oral EPO treatment (5). Based on a number of such studies (6), a product license has been granted to at least one pharmaceutical company under the label "Epogam" for the treatment of eczema. In many countries, including Australia, numerous EPO brands are available in pharmacies and health food stores. We report here a systematic study on the fatty acids of a range of EPO products which we measured using sensitive capillary column gas chromatography.
MATERIALS AND METHODS EPO capsules were obtained from pharmacies and health food stores in Sydney, Melbourne and Adelaide and, where possible, more than one batch number of each product was purchased. All capsules tested were in the soft gelatin form. The retail cost varied and ranged from AS 0.19 to AS 0.52 per capsule. All EPO samples were tested against a standard that had been extracted from evening primrose seed in our laboratory. Seeds (5 g) were homogenized in 30 mL of petroleum hydrocarbon and the homogenate centrifuged. The supernatant was decanted and the sediment extracted twice with 30-mL washes of petroleum hydrocarbon. The combined supernatants were filtered and the solvent *To whom correspondenceshould be addressed. Abbreviations: EPO, evening primrose oil; GLA, ),-linoleulc acid (18:3n-6); LA, linoleicacid (18:2n-6);MUFA, monounsaturatedfatty acids; SFA, saturated fatty acids; TLC, thin-layerchromatography. LIPIDS, Vol. 27, no. 1 (1992)
evaporated. Thin-layer chromatography (TLC) revealed that only triglycerides were present. Fatty acid analysis. TLC showed that all commercial products were predominantly in the triglyceride form. EPO was removed from capsules and 1-2 ~L added to glass vials without further purification. Five mL of a solution of 1% H2SO4 in methanol was added to each vial. Vials were sealed and heated at 70~ for 3 hr. After cooling, the resulting methyl esters were extracted with 2 mL n-heptane. The extract was transferred into 2-mL auto sampler vials containing anhydrous sodium sulfate. Fatty acid methyl esters were separated on a wide bore (0.56 ram) 50-m capillary column coated with SP 2340 (Supelco Inc, Bellefonte~ PA) using a Hewlett Packard 5880 gas chromatograph (Hewlett Packard, Palo Alto, CA). Chromatographic conditions were those described in detail elsewhere (7). Helium was used as the carrier gas at a flow of 30 cm/sec. The oven temperature was increased from 120~ to 200~ at 5~ per min; injection temperature was held at 250 ~ and flame ionization detector temperature was 300~ Samples (1 ~L) were injected using the split mode at a 30:1 ratio. Variation. All products were sampled in triplicate. Variation in major peaks was less than 5%, while the variation in minor peaks (20%) of saturates measured in Nature's Own Plus are due to oils present in an added vitamin/mineral mix. Examination of the minor components of the products showed interesting differences between brands. Several brands contained detectable amounts of C22 and C24 monounsaturated fatty acids (MUFA), which were not found in our laboratory standard EPO. While it is possible that these low levels of C22 and C24 MUFA are due to genetic differences among the various strains of evening primrose, we consider this unlikely. Analysis of oil extracted in our laboratory from seeds of evening primrose strains from Europe, China, Australia, New Zealand and North America has failed to reveal the presence of these MUFA.
83 COMMUNICATION TABLE 1
Fatty Acid Compositiona of Different Brands of Evening Primrose Oil Capsules Brand b
B a t c h no.
Label GLA c
GLA
LA
Total SFA d
Total MUFA e
20:1n-9
22:1n-ll
24:1n-9
10 10 10 8 8 8 8 8 8 8 8 10 10 10 10 10 10 10 10 10 10 8 8 8 7.9 7.9 7.9 7.9 9-10 10 10 10 8 10
9.8 9.6 9.2 9.5 8.2 8.2 9.0 8.0 7.6 8.6 8.0 10.1 10.1 9.1 10.4 10.0 9.8 8.8 10.0 10.0 9.0 9.3 8.2 6.3 7.6 7.7 7.4 7.1 10.5 10.5 9.6 9.5 7.6 9.1
72.2 71.2 71.4 71.9 71.1 73.9 69.4 73.1 71.2 74.1 74.3 65.5 65.5 65.5 65.3 65.9 63.5 69.9 63.2 65.5 65.3 74.3 74.7 67.7 59.7 60.1 64.5 63.0 64.0 64.0 72.6 73.3 74.1 64.9
8.5 8.9 9.4 8.4 8.1 8.8 8.5 8.9 8.1 8.3 8.8 9.2 9.2 9.3 9.0 8.8 9.7 9.6 9.2 8.9 9.4 8.4 8.3 10.4 24.2 23.8 26.2 26.3 9.2 9.2 8.5 9.2 8.9 9.6
9.3 10.2 9.8 10.1 12.4 8.9 11.8 9.9 13.1 8.9 8.9 15.2 15.2 16.1 15.5 15.3 16.9 11.6 16.2 15.5 16.4 7.9 8.7 15.3 8.1 8.0 9.9 11.1 16.3 16.2 9.1 7.6 9.3 16.4
0.13 0.21 0.18 0.12 0.13 0.16 0.31 0.13 0.14 0.15 0.16 0.84 0.83 0.80 0.84 0.74 1.00 0.64 0.88 0.80 0.81 0.14 0.15 0.21 0.12 0.12 0.16 0.16 0.95 0.91 0.14 0.15 0.16 0.89
------0.84 ----0.47 0.47 0.46 0.45 0.42 0.60 0.30 0.52 0.45 0.47 --0.09 ----0.53 0.53 ---0.49
-----------0.26 0.26 0.24 0.25 0.22 0.33 0.18 0.29 0.24 0.26 -------0.31 0.30
Soul P a t t i n s o n N a t u r a l Care
30924 30130 30927 30234 23038 23634 24253 29317 22994 23600 23749 A0233 A0139 30305 90835 00422 2900 1039 M9830 E0974 M0093 5987B 3261-2 3064 32315 32315 3399A 34941 07 08 33915 34562 56727 16969
Amcal MicroGenics Moonkist EPO
36439 8481 190
8 10 5.2
8.2 9.7 1.9
74.6 70.0 75.8
8.4 9.4 13.7
8.7 10.8 8.6
0.14 0.58 0.15
-0.28 --
-0.17 --
Naudicelle
Efamol
Eviprim Blackmores
Natural Nutrition
Healtheries
Nature's Own
Bioglan
Nature's Own Plus
Good Health Macro
--0.28
a V a l u e s are m e a n s g i v e n as % w e i g h t of t o t a l f a t t y acids. b T h e following p r o d u c t s were s a m p l e d : Nandicelle (Key P h a r m a c e u t i c a l s P t y . L t d . R h o d e s , N.S.W. Australia}; E f a m o l (Efamol, L o n d o n , England}; E v i p r i m {Key P h a r m a c e u t i c a l s Pty. Ltd.}; B l a c k m o r e s B o t a n i c a l s ( B l a c k m o r e s Ltd. B a l g o w l a h , N.S.W. Australia}; N a t u r a l Nutrition, N a t u r e ' s O w n a n d N a t u r e ' s O w n P l u s (Natural H e a l t h P r o d u c t s Pty. Ltd., Kippa-Ring, Q.L.D. Australia); Healtheries (Healtheries of N e w Zealand, A u c k l a n d , N e w Zealand}; B i o g l a n [Bioglan L a b o r a t o r i e s {Aust.) Pty. Ltd., MarrickviUe, N.S.W. Australia]; Good H e a l t h {Good H e a l t h P r o d u c t s , A u c k l a n d , N e w Zealand); M a c r o (Lederle L a b o r a t o r i e s Division, C y a n a m i d A u s t r a l i a Pty. Ltd., B a u l k h a m Hills, N.S.W. Australia}; Soul P a t t i n s o n [Soul P a t t i n s o n {Laboratories) P t y . Ltd., K i n g s g r o v e , N.S.W. A u s t r a l i a ] ; N a t u r a l Care A u s t r a l i a , B r u n s w i c k H e a d s , N.S.W. Australia}; A m c a l {Allied M a s t e r C h e m i s t s of A u s t r a l i a L i m i t e d , S p r i n g v a l e , V.I.C. Australia); Micro Genics {Twin L a b s Pty. Ltd., W i n d s o r , V.I.C. Australia}; M o o n k i s t {Gum P a r k Pty. Ltd., C a n n a w i g a r a S.A. Australia}. c % A s listed b y m a n u f a c t u r e r . d I n c l u d e s 14:0, 15:0, 16:0, 17:0, 18:0, 20:0, 22:0 a n d 24:0. e I n c l u d e s 14:1, 15:1, 16:1, 17:1, 18:1, 20:1, 22:1 a n d 24:1.
TABLE 2 Fatty Acid Compositiona of EPO, Borage and Safflower Oils
EPO Borage E P O / B o r a g e (84:16) B o r a g e / S a f f l o w e r (60:40)
GLA 18:3n-6
LA 18:2n-6
Total SFA b
Total MUFA c
20:1n-9
22:1n-ll
24:1n-9
7.0 26.1 9.8 9.8
69.7 38.1 64.9 60.9
8.2 12.6 8.8 10.8
15.0 22.8 16.4 18.3
0.24 4.31 0.79 1.94
-2.70 0.46 1.27
-1.56 0.25 0.90
a V a l u e s are m e a n s g i v e n as % w e i g h t of t o t a l f a t t y acids, 15:1, 16:1, 17:1, 18:1, 20:1, 22:1, a n d 24:1.
b I n c l u d e s 14:0, 15:0, 16:0, 17:0, 18:0, 20:0, 22:0 a n d 24:0.
c I n c l u d e s 14:1,
LIPIDS, Vol. 27, no. 1 (1992)
84
COMMUNICATION We investigated the possibility t h a t some of the capsules contained blends of E P O and either borage or safflower oil (Table 2). Starting with an E P O sample with 7% GLA, blends of oils were prepared which were designed to achieve a G L A level of 10%. The f a t t y acid profile of the EPO/Borage oil blend (84:16) more closely m a t c h e d the profile seen in some of the capsules t h a n the Borage]Safflower blend 160:40). G L A is the claimed active ingredient of E P O and, thus, consumers and researchers alike are interested in the G L A content of E P O products. Although the levels of G L A in the products tested in this s t u d y were in the range expected for EPO, minor constituents in some products suggested t h a t some m a y contain contaminants of other oils. Unlike marine oils t8), E P O is relatively easy to analyze (particularly by capillary gas chromatography) as it contains only two major polyunsaturated f a t t y acids {LA and GLA), and sometimes low levels of a-linolenic acid (18:3n-3) E P O is devoid of C22 and C24 MUFA t h a t are present in some other GLA-containing oils, such as borage (9). Despite this, several of the products t h a t we tested were found to contain a m o u n t s of 20:1, 22:1 and 24:1 consistent with a blend of borage and E P O {Table 2). I t is interesting t h a t m o s t of the capsules t h o u g h t to contain EPO/borage blends also contained G L A levels close to 10% of the total f a t t y acids. W h e t h e r this represents an a t t e m p t by manufacturers to supply oils with a s t a n d a r d G L A content or is the result of accidental contamination during pressing and/or extraction is unknown.
LIPIDS, Vol. 27, no. 1 (1992)
There are no reports of the c o m p a r a t i v e physiological or clinical effects of the various G L A containing oils in humans. Until this is done, the significance of capsules of E P O containing low levels of borage or other oils remains largely one of labelling.
REFERENCES 1. Gibson, R.A., and Rassias, G. (1990) in Omega-6 Essential Fatty Acids: Pathophysiology and Roles in Clinical Medicine (Horrobin, D., ed.) pp. 283-293, Alan R. Liss, New York. 2. Ockermarm, RA., Backrack, I., Glans, S., and Rassner, S. 11986) Rec. Adv. Clin. Nutr. 2, 404-405. 3. Belch, J.J.F., Ansell, D., Madhock, R., O'Dowd, A., and Sturrock, R.D. 11988)Am. Rheum. Dis. 47, 96-100. 4. Mansel, R.E., Py~ J.K., and Hughes, L.E. 11990)in Omega~ Essential Fatty Acids: Pathophysiology and Roles in Clinical Medicine
(Horrobin, D., ed.) pp. 557-566, Alan R. Liss, New York. 5. Wright, S., and Burton, J.L. 11982) Lancet ii, 1120-1125. 6. Morse, RE., Horrobin, D.E, Manku, M.S., Stewart, J.C.M., Allen, R., Littlewood, S., Wright, S., Burton, J., Gould, D.J., Holt, P.J., Jansen, C.T.,Mattila, L., Meigel, W., Dettke, T.H., Wexler, D., Guenther, L., Bordoni, A., and Patrizi, A. 11989) Br. J. Dermatol. 121, 75-90. 7. James, M.J., Cleland, L.G., Gibson, R.A., and Hawkes, J.S. 11991) J. Nutr. 121, 631-637. 8. Ackman, R.G. 11987)Acta Meal Scand 222, 99-105. 9. Muderhwa, J.M., Dhuique-Mayer, C., Pina, M., Galzy, E, Grignae, P., and Graille, J. 11987) Oleagineux 42, 207-211. [Received July 26, 1991; Revision accepted October 4, 1991]
