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Gamma-linolenic acid (GLA)
composition and properties
of blackcurrant seed oil
Blackcurrant Seed Oil SabaLine capsules contain the pure and natural oil from black currant seeds, one the world's richest source of gamma-linolenic acid (GLA).
It is well known that dietary oils and fats have numerous functions; they are in particular :
- a source of energy
- a source of structural lipids (cell membranes, tissues)
- a source of essential fatty acids necessary to the synthesis of long chain polyunsaturated fatty acids and prostaglandins
- a vehicle of liposoluble vitamins (A, D, E and K)
- a factor influencing many metabolisms (blood lipid content, immune functions)
The work of Burr and Burr, published in 1930, highlighted that animals on fat deficient diets, would show skin and hepatic anomalies as well as growth and reproduction disorders. These phenomena could be reversible by addition to the diet of certain unsaturated fatty acids. These fatty acids that the organism is not able to synthesise, have been defined as essential fatty acids (EFA) and have even received the denomination Vitamin F. They consist of linoleic acid (C 18:2, n-6) and alpha-linolenic acid (C 18:3, n-3). Subsequently, it was demonstrated that the biological activity of EFA was depending of their derivatives or higher homologous involved in the synthesis of biologically active molecules named eicosanoids (prostaglandins, leukotrienes, thromboxanes and prostacyclines). Eicosanoids regulate many cell functions. They are active in the fields of inflammation, blood coagulation, reproduction, renal function, etc...
The biosynthesis of higher homologous and eicosanoids is under the dependency of enzymes. The young and healthy body is able to assure this transformation starting from EFA. However, in some physiological or pathological situations, these fatty acids are not efficiently metabolised. This happens especially in :
- ageing
- stress
- hepatic deficiency
- alcohol consumption
- diabetes
- treatment with corticoids
In these different situations, one particular enzyme, delta-6-desaturase, has a low activity. Therefore, it was important to find an oil containing fatty acids having already passed this limiting step of transformation of the EFA. The fatty acids resulting from the action of delta-6-desaturase are the gamma-linolenic acid or GLA (C 18:3, n-6) and the stearidonic acid (C 18:4, n-3).
Unfortunately, no standard dietary oil provides these two fatty acids. For a few years, two oils, Evening Primrose oil and Borage oil, providing respectively 7% and 23% of GLA, have been on the market. A third oil containing GLA was discovered later; it is Blackcurrant seed oil (BCO) which has the advantage of containing not only an important quantity of gamma-linolenic acid (15 to 19% of GLA), but also stearidonic acid. The two fatty acids resulting from the limiting step of transformation from EFA are therefore present in BCO, under a form ready-to-use by the organism. Thanks to the direct supply of gamma-linolenic acid and stearidonic acid, the obstacle of the delta-6-desaturase is then by-passed.
Blackcurrant seed oil is very rich in polyunsaturated fatty acids, providing less than 10% of saturated fatty acids. It is also important to underline that Blackcurrant seed oil is particularly well balanced between the two families of n-6 and n-3 fatty acids. Indeed, recommendations from nutritionists indicate that the ideal ratio n-6/n-3 in the diet should be in the range of 5/1. This ratio is in reality around 10/1 in occidental countries. From this point of view, Blackcurrant seed oil is well balanced as the ratio is around 4/1, which is rather rare among vegetable oils.
Composition of fatty acids in BCO:
| palmitic acid |
C 16:0 |
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6 - 8% |
| stearic acid |
C 18:0 |
|
1 - 2% |
| oleic acid |
C 18:1 |
n - 9 |
10 - 15% |
| linoleic acid |
C 18:2 |
n - 6 |
43 - 51% |
| gamma-linolenic acid |
C 18:3 |
n - 6 |
15 - 19% |
| alpha-linolenic acid |
C 18:3 |
n - 3 |
11 - 15% |
| stearidonic acid |
C 18:4 |
n - 3 |
2 - 4% |
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