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Black Currant and Borage Oil Medicinal Uses Interactions Side Effects Dosage
Black Currant and Borage Oil Several parts of the black currant (Ribes nigrum) and borage (Baraga officinalis) plants are used medicinally. Black currant berries are also called quinsy berries, and borage seed oil is also called startlower oil. The plant oils are derived from the berries or seeds.
Uses and Benefits:
Historically, the leaves of black currant and borage plants have been used for various rheumatic and inflammatory conditions, and as herbal diuretics. Black currant has also been used for diarrhea, while borage has also been used as an antipyretic, expectorant, and general tonic. Currently, both plant oils are employed as rich sources of gamma-linolenic acid (GLA). Along with evening primrose oil, these GLA-containing oils are used for chronic inflammatory and other conditions such as eczema, rheumatic disorders, mastalgia, premenstrual syndrome, and diabetic neuropathy.1-4 Patients with these disorders are thought to be unable to sufficiently convert their dietary essential fatty acids to GLA, a precursor of anti-inflammatory eicosanoids 5; thus, supplementation with GLA-rich plant oils is considered beneficial.
Pharmacology:
The richest plant source of GLA is borage seed oil (about 23%), followed by black currant oil (15-20%) and evening primrose oil (7-10%).15 The borage plant also contains small amounts of pyrrolizidine alkaloids (highest in the leaves and stems), mucilages, saponins, and tannins. Black currant contains flavonoids, proanthocyanidins, and tannins, and the oil is also rich in alpha-linoleic acid; this can be converted in the body to eicosapentanoic acid, which is also found in fish oils.
The metabolic pathway of GLA has been well established in humans and other animals. Dietary linoleic acid (LA), an essential fatty acid, is converted to GLA by a rate-limiting enzymatic step.GLA is then rapidly converted to dihomo-gammalinolenic acid (GLA), which is further metabolized to 1-series prostaglandins (PGs, such as PGE 1 ) and 3-series leukotrienes (LTs), which have mti-nflammatory properties, and to arachidonic acid (AA) in limited amounts. AA is converted by cyclo-oxygenases and lipoxyge to pro-inflammatory mediators such as the 2-series prostaglandins
GLA supplementation has been shown to attenuate the in vitro inflammatory response by enriching cells with DGLA, the immedi?ate precursor of PGE 1 , without increasing synthesis of AA.5 DGLA or another metabolite, 15-hydroxy-DGLA, appears to inhibit the AA pathway to its inflammatory byproducts, further inhibiting in?flammation, and also has direct immune modulating effects on T?lymphocytes. A variety of anti-inflammatory effects from GLA supplementation has been demonstrated in animals and humans.
Most pharmacologic studies used evening primrose oil as the source of GLA. However, borage oil (and to a lesser extent, black currant oil) supplementation in humans has similarly been found to increase cellular DGLA concentrations, and to have im?munomodulatory activity by altering cytokine production.
Based on an elevated ratio of PGE to pro-aggregatory eicosanoids, GLA is expected to reduce platelet aggregation. Controlled studies in humans have reported varying results, how? ever, with most studies reporting an increase or no change in ag?gregation. Bleeding time data has not been evaluated.
Clinical Trials:
. Dermatitis-Atopic dermatitis and infantile seborrheic der?matitis have been the subject of several GLA supplementation studies from Germany. Small placebo-controlled studies of borage or black currant oil with doses providing up to 600 mg/day of GLA reported both positive and negative results. The largest and most rigorous study of borage oil (providing 690 mg/day GLA) failed to find a significant benefit in the intention-to?treat group. This was a randomized, double-blind, placebo-con?trolled trial of 160 patients with atopic dermatitis, in which 6 months of supplementation was no more effective than placebo.Subgroup analysis found benefits in specific populations. Similarly, while early trials of atopic dermatitis using evening prim?rose oil reported benefits, more recent and better controlled trials have been disappointing. Thus, while the doses used were rela?tively low, clear benefits with GLA-containing oils for atopic der?matitis have not been demonstrated.
Rheumatoid Arthritis-In patients with rheumatoid arthritis, chronic low doses of evening primrose oil (providing 540 mg/day GLA) have shown conflicting results in two separate trials. Larger doses of GLA from borage or black currant oil were generally more successful in three double-blind, randomized, controlled trials from the same research group, all lasting 6 months. In the two trials using borage oil (n = 37 and 56), daily doses provided 1.4 g and 2.8 g of GLA, respectively. Both of these trials found modest but statistically significant improvements overall, along with improvements in specific signs and symptoms such as joint tenderness, swelling, and pain assessments at 6 months.
In the higher-dose study, patients in the treatment group were 6.5 times more likely than placebo to experience meaningful im?provement at 6 months, and the placebo group was 4 times more likely to experience deterioration. 21 Statistically significant improvements were not seen at interval checks prior to 6 months.
In the trial using black currant oil (providing 2 g/day GLA) in 34 subjects, the investigators found no improvements in global as?sessment, pain, swelling, or stiffness, but the joint tenderness score improved statistically compared to placebo (soybean oil).
Adverse Effects:
GLA-containing plant oils are well tolerated in clinical trials lasting up to 1 year. A few cases of diarrhea or soft stools, belching, and abdominal bloating have been reported.
Side Effects and Interactions:
There are no recognized drug interactions.
Cautions: Although controversial, there is concern that borage oil may contain small amounts of toxic pyrrolizidine alkaloids (PAs), which are found in the leaves and stems of the plant. Unsaturated PAs found in other plants are known to cause severe veno-occlusive hepatotoxicity in animals and humans, and carcinogenic and mutagenic effects in animal models. There are no reports of hepatotoxicity with borage plants or products, probably due to the very low concentrations of these alkaloids, and the seeds and oil of borage may contain insignificant amounts. However, without official quality standards and regulations, American consumers have no way of knowing the PA content of borage oil supplements. Additionally, data regarding the use of black currant and borage oils during pregnancy and lactation is lacking.
Preparations & Doses: Most GLA-containing oils are manufactured in capsule (or softgel) form; they are also available as pure bottled liquid. Capsules may contain about 1000-1300 mg or more of oil (170-300 mg GLA, depending on the plant source). 10 attain daily GLA supplementation of at least 1-2 g, the dose lound to be effective in most controlled studies, 3-12 capsules/day are needed, depending on the product. More traditional preparations of the leaf parts include infusions and tinctures.
Summary Evaluation
Black currant and borage oils are the richest known plant sources of GLA, an omega-6 fatty acid and precursor to anti-inflammatory cicosanoids. Preliminary results from studies of inflammatory skin disease such as atop ic dermatitis were hopeful, but generally poor results were found in larger or better-quality trials. Larger doses benefited patients with rheumatoid arthritis in limited trials; this herbal remedy may be helpful in some of these patients. A practical limitation to the use of GLA-containing plant oils is the large number of capsules needed for adequate dosing, and the long onset of action (several months) before clinical benefits are observed.
Steve Mathew is a writer, who writes many great articles on herbal medicines and ayurvedic medicines for common ailments and diseases. Visit us for more information on herbal remedies and ayurvedic medicines
By: Steve Mathew
Black Currant and Borage Oil Several parts of the black currant (Ribes nigrum) and borage (Baraga officinalis) plants are used medicinally. Black currant berries are also called quinsy berries, and borage seed oil is also called startlower oil. The plant oils are derived from the berries or seeds.
Uses and Benefits:
Historically, the leaves of black currant and borage plants have been used for various rheumatic and inflammatory conditions, and as herbal diuretics. Black currant has also been used for diarrhea, while borage has also been used as an antipyretic, expectorant, and general tonic. Currently, both plant oils are employed as rich sources of gamma-linolenic acid (GLA). Along with evening primrose oil, these GLA-containing oils are used for chronic inflammatory and other conditions such as eczema, rheumatic disorders, mastalgia, premenstrual syndrome, and diabetic neuropathy.1-4 Patients with these disorders are thought to be unable to sufficiently convert their dietary essential fatty acids to GLA, a precursor of anti-inflammatory eicosanoids 5; thus, supplementation with GLA-rich plant oils is considered beneficial.
Pharmacology:
The richest plant source of GLA is borage seed oil (about 23%), followed by black currant oil (15-20%) and evening primrose oil (7-10%).15 The borage plant also contains small amounts of pyrrolizidine alkaloids (highest in the leaves and stems), mucilages, saponins, and tannins. Black currant contains flavonoids, proanthocyanidins, and tannins, and the oil is also rich in alpha-linoleic acid; this can be converted in the body to eicosapentanoic acid, which is also found in fish oils.
The metabolic pathway of GLA has been well established in humans and other animals. Dietary linoleic acid (LA), an essential fatty acid, is converted to GLA by a rate-limiting enzymatic step.GLA is then rapidly converted to dihomo-gammalinolenic acid (GLA), which is further metabolized to 1-series prostaglandins (PGs, such as PGE 1 ) and 3-series leukotrienes (LTs), which have mti-nflammatory properties, and to arachidonic acid (AA) in limited amounts. AA is converted by cyclo-oxygenases and lipoxyge to pro-inflammatory mediators such as the 2-series prostaglandins
GLA supplementation has been shown to attenuate the in vitro inflammatory response by enriching cells with DGLA, the immedi?ate precursor of PGE 1 , without increasing synthesis of AA.5 DGLA or another metabolite, 15-hydroxy-DGLA, appears to inhibit the AA pathway to its inflammatory byproducts, further inhibiting in?flammation, and also has direct immune modulating effects on T?lymphocytes. A variety of anti-inflammatory effects from GLA supplementation has been demonstrated in animals and humans.
Most pharmacologic studies used evening primrose oil as the source of GLA. However, borage oil (and to a lesser extent, black currant oil) supplementation in humans has similarly been found to increase cellular DGLA concentrations, and to have im?munomodulatory activity by altering cytokine production.
Based on an elevated ratio of PGE to pro-aggregatory eicosanoids, GLA is expected to reduce platelet aggregation. Controlled studies in humans have reported varying results, how? ever, with most studies reporting an increase or no change in ag?gregation. Bleeding time data has not been evaluated.
Clinical Trials:
. Dermatitis-Atopic dermatitis and infantile seborrheic der?matitis have been the subject of several GLA supplementation studies from Germany. Small placebo-controlled studies of borage or black currant oil with doses providing up to 600 mg/day of GLA reported both positive and negative results. The largest and most rigorous study of borage oil (providing 690 mg/day GLA) failed to find a significant benefit in the intention-to?treat group. This was a randomized, double-blind, placebo-con?trolled trial of 160 patients with atopic dermatitis, in which 6 months of supplementation was no more effective than placebo.Subgroup analysis found benefits in specific populations. Similarly, while early trials of atopic dermatitis using evening prim?rose oil reported benefits, more recent and better controlled trials have been disappointing. Thus, while the doses used were rela?tively low, clear benefits with GLA-containing oils for atopic der?matitis have not been demonstrated.
Rheumatoid Arthritis-In patients with rheumatoid arthritis, chronic low doses of evening primrose oil (providing 540 mg/day GLA) have shown conflicting results in two separate trials. Larger doses of GLA from borage or black currant oil were generally more successful in three double-blind, randomized, controlled trials from the same research group, all lasting 6 months. In the two trials using borage oil (n = 37 and 56), daily doses provided 1.4 g and 2.8 g of GLA, respectively. Both of these trials found modest but statistically significant improvements overall, along with improvements in specific signs and symptoms such as joint tenderness, swelling, and pain assessments at 6 months.
In the higher-dose study, patients in the treatment group were 6.5 times more likely than placebo to experience meaningful im?provement at 6 months, and the placebo group was 4 times more likely to experience deterioration. 21 Statistically significant improvements were not seen at interval checks prior to 6 months.
In the trial using black currant oil (providing 2 g/day GLA) in 34 subjects, the investigators found no improvements in global as?sessment, pain, swelling, or stiffness, but the joint tenderness score improved statistically compared to placebo (soybean oil).
Adverse Effects:
GLA-containing plant oils are well tolerated in clinical trials lasting up to 1 year. A few cases of diarrhea or soft stools, belching, and abdominal bloating have been reported.
Side Effects and Interactions:
There are no recognized drug interactions.
Cautions: Although controversial, there is concern that borage oil may contain small amounts of toxic pyrrolizidine alkaloids (PAs), which are found in the leaves and stems of the plant. Unsaturated PAs found in other plants are known to cause severe veno-occlusive hepatotoxicity in animals and humans, and carcinogenic and mutagenic effects in animal models. There are no reports of hepatotoxicity with borage plants or products, probably due to the very low concentrations of these alkaloids, and the seeds and oil of borage may contain insignificant amounts. However, without official quality standards and regulations, American consumers have no way of knowing the PA content of borage oil supplements. Additionally, data regarding the use of black currant and borage oils during pregnancy and lactation is lacking.
Preparations & Doses: Most GLA-containing oils are manufactured in capsule (or softgel) form; they are also available as pure bottled liquid. Capsules may contain about 1000-1300 mg or more of oil (170-300 mg GLA, depending on the plant source). 10 attain daily GLA supplementation of at least 1-2 g, the dose lound to be effective in most controlled studies, 3-12 capsules/day are needed, depending on the product. More traditional preparations of the leaf parts include infusions and tinctures.
Summary Evaluation
Black currant and borage oils are the richest known plant sources of GLA, an omega-6 fatty acid and precursor to anti-inflammatory cicosanoids. Preliminary results from studies of inflammatory skin disease such as atop ic dermatitis were hopeful, but generally poor results were found in larger or better-quality trials. Larger doses benefited patients with rheumatoid arthritis in limited trials; this herbal remedy may be helpful in some of these patients. A practical limitation to the use of GLA-containing plant oils is the large number of capsules needed for adequate dosing, and the long onset of action (several months) before clinical benefits are observed.
Steve Mathew is a writer, who writes many great articles on herbal medicines and ayurvedic medicines for common ailments and diseases. Visit us for more information on herbal remedies and ayurvedic medicines
By: Steve Mathew
