Name: Evening Primrose Oil, Oneothera biennis
Active Compounds: Gamma linolenic acid
Goes well with: Alpha Lipoic Acid, Vitamin E
Number of scientific references: 18
Level of Evidence: Level II What is this?
Note: Evening primrose oil assists in restoring nerve function in peripheral neuropathy by proving gamma-linolenic acid. Robust clinical trials are needed to confirm its therapeutic effectiveness. At present, there is insufficient evidence to recommend the use of evening primrose oil in peripheral neuropathy treatment.
Evening primrose oil (EPO) is extracted from the seeds of the plant Oenothera biennis. It is used as a dietary supplement since it is rich in essential omega-6 fatty acids.
Evening primrose was a staple food for Native Americans; its roots, leaves, flowers and buds can be consumed. Traditionally it was used to treat stomach aches, bruises, wounds, skin inflammation, shortness of breath etc.
Research has examined its efficacy in atopic dermatitis, mastalgia, rheumatoid arthritis, cholesterol, atherosclerosis, premenstrual syndrome etc.
Evening primrose seed contains about 14% fixed oil which contains 65–75% linoleic acid, 7–10% gamma-linolenic acid (GLA), oleic, palmitic, and stearic acids and steroids.
The gamma-linolenic acid content contributes to the health benefits of the oil. Linolenic acid and alpha-linolenic acid are essential fatty acids that are converted to GLA, DHA, EPA in the body and these metabolites play an important role in the inflammatory process.
By directly providing GLA, the oil skips the rate-limiting step of converting linolenic acid. GLA is then directly converted to DGLA or dihomogammalinolenic acid which is a precursor of anti-inflammatory agents in the body.
Therefore evening primrose oil is thought to be beneficial for chronic inflammatory conditions, but at this stage, the evidence regarding its efficacy is limited and preliminary.
Evening primrose oil benefits in peripheral neuropathy by restoring nerve function. It improves blood flow and rectifies metabolic abnormalities to protect nerve health. It may also assist in nerve regeneration. But, at present, there is insufficient evidence to recommend evening primrose oil for peripheral neuropathy treatment.
What does research say about the effect of Evening primrose oil in Peripheral Neuropathy?
Pre-clinical studies have proven multiple pharmacological properties of EPO that can benefit in peripheral neuropathy. A few human studies have found GLA beneficial in reducing diabetic neuropathy symptoms. Let’s have a look at the research available to date.
1.GLA in evening primrose oil helps in diabetic neuropathy
Most of the research on evening primrose oil and peripheral neuropathy is focused on diabetic neuropathy. Pre-clinical studies show that EPO acts on various aspects of diabetic neuropathy.
Table of Contents
- 1 What does research say about the effect of Evening primrose oil in Peripheral Neuropathy?
- 2 Dosage of Evening Primrose Oil For Peripheral Neuropathy
- 3 Precautions with Evening Primrose Oil Use
- 4 Conclusion
High blood sugar levels, alterations in the pancreas cells, irregular fat metabolism, disruption of blood flow damage the structure of nerves in diabetes. The myelin sheath around the nerve cell degenerates, the nerve fibres begin to separate, the axon length decreases etc.
Treatment with evening primrose oil prevents such structural damages to the nerve cells. It inhibits myelin degeneration and protects axon length.
Evening primrose oil prevents peripheral nerve dysfunction in diabetes. It rectifies nerve conduction velocity which is reduced in diabetes.
Gamma linolenic acid and its metabolite DLMG are the active components of the oil that protect nerve function by improving blood flow to the nerves. EPO counteracts metabolic changes that affect nerve function such as anticoagulant status, high cholesterol levels and restore normal blood flow to the nerves.
Dines et al. conducted a study to assess the effect of various natural oils, rich in GLA, on diabetic neuropathy. They included blackcurrant oil, borage oil and fungal oil and compared them with evening primrose oil.
Among all the GLA-rich oils, EPO offered maximum protection against diabetic neuropathy and restored nerve function.
Recently Elkoussi et al. demonstrated via an animal study, that EPO improves blood sugar control, antioxidant capacity and fat/lipid abnormalities; these effects help restore peripheral nerve function. The oil’s protective action against diabetic neuropathy is improved by concurrent administration of insulin or alpha lipoic acid.
In 1990, Jamal and Carmichael conducted the first human study on GLA and diabetic neuropathy. 22 patients with distal diabetic polyneuropathy were enrolled in the study. They were treated with 360 mg GLA or placebo daily for six months.
Compared to the placebo group, GLA group showed a decrease in neuropathy scores, improved nerve function and increased resistance to pain caused by extreme temperatures.
In 1993, Keen et al. treated 111 patients having mild diabetic neuropathy with GLA (480 mg/day) for one year. Over the one year period, the GLA group experienced improvement in nerve function, sensation, pain sensitivity as well as muscle strength.
Quick Gist: Pre-clinical studies demonstrate the treatment with evening primrose oil prevents structural abnormalities and changes in nerve function in diabetic neuropathy. Very few human studies have been conducted to date on EPO and diabetic neuropathy; they show positive results with GLA treatment for 6-12 months.
Further research in the form of robust clinical trials is necessary before recommending EPO for peripheral neuropathy.
2.It may help in nerve repair and regeneration
Evening primrose oil provides gamma-linolenic acid which regulates the inflammatory process and aids in the production of anti-inflammatory mediators. This activity assists in nerve repair.
GLA supplementation improves the fatty acid composition of the nerve membrane and restores nerve function.
It also balances metabolic changes and blood flow to the damaged nerves and thus restores nerve function.
A recent study published in Evidence-Based Alternative and Complementary Medicine, 2017 highlighted the nerve regenerating potential of EPO in case of damaged nerves.
The oil supported re-myelination and growth of axons in damaged nerves. The shape of the nerve cells, the thickness of the myelin sheath and diameter of axons in the group treated with oil was almost the same as the normal group.
Electrical stimulation or providing monitored electrical impulses is proven to improve symptoms of peripheral neuropathy. Combination of evening primrose oil and electrical stimulation may enhance nerve regeneration and restore nerve function in damaged peripheral nerve.
Quick Gist: Evening primrose oil restores nerve function in damaged nerves by improving blood flow, reducing metabolic abnormalities and improving the composition of nerve membrane. It may assist in nerve regeneration by reducing inflammation.
3.It can help reduce inflammation
The anti-inflammatory action of evening primrose oil contributes to most of its health benefits. The omega-6 fatty acid content of the oil skips the rate-limiting step in the inflammatory process and gives rise to the production of anti-inflammatory agents.
This activity helps reduce inflammation and pain and even benefits in autoimmune conditions.
The esters and long chain fatty alcohols in the oil have proven anti-inflammatory activity. Dietary evening primrose oil prevents abnormal stimulation of immune cells which would otherwise cause inflammation.
These properties of EPO can benefit in inflammatory and autoimmune-mediated neuropathies.
The oil also has antioxidant activity which can help mitigate oxidative stress occurring in peripheral neuropathy.
Inflammatory mediators play an important role in pain transmission. Though not studied about nerve pain, the use of evening primrose oil in other chronic pain conditions has been investigated.
Ranieri et al. conducted a clinical trial to investigate the effect of Alpha lipoic acid and Gamma Linolenic acid in back pain. Alpha lipoic acid is proven to help in peripheral neuropathy significantly.
203 patients with neuropathic pain occurring as a result of ‘compressive radiculopathy syndrome from disc-nerve root conflict’ were enrolled in the study.
Patients were assigned to ALA, GLA and rehabilitation group or only rehabilitation group. The ALA and GLA group received 600mg ALA, 360mg GLA and a rehabilitation program for six weeks.
Significant reduction in low back pain was observed in ALA and GLA group; improvements in burning pain, stabbing pain and abnormal pain sensations was observed in this group.
There was a reduction in disability score and quality of life improved. Researchers concluded that ALA and GLA along with rehabilitation therapy for six weeks improves neuropathy symptoms in patients with radicular neuropathy.
Quick Gist: EPO has anti-inflammatory and antioxidant properties that can benefit in peripheral neuropathy, but this needs to be confirmed in human studies. Combined therapy with ALA and GLA is proven to relieve neuropathic pain.
Dosage of Evening Primrose Oil For Peripheral Neuropathy
Evening primrose oil is available in capsules or liquid form. The recommended dose of the oil is 2-3g per day.
Standardized EPO supplements must contain 8-9% gamma-linolenic acid and 72% linoleic acid per dose.
Very few human studies have examined the effects of evening primrose oil in peripheral neuropathy. The recommended dose is 500mg of evening primrose oil capsule daily or 360 mg to 480 mg GLA from evening primrose oil daily for six months.
Topical application of evening primrose oil is used to relieve pain, but its efficacy for nerve pain has not been ascertained.
Please consult a health practitioner before taking evening primrose oil supplements.
Precautions with Evening Primrose Oil Use
Evening primrose oil is well-tolerated, and no side effects have been reported when used in the short term.
The most common adverse effects are gastrointestinal side effects (abdominal pain, nausea, diarrhoea) and headaches. EPO may be consumed immediately after consuming food to avoid gastric side effects.
It may increase bleeding risk in individuals with a bleeding disorder or taking anticoagulants such as warfarin. Discontinue its use 15 days before surgery.
Avoid using evening primrose oil when taking anticonvulsants or phenothiazine neuroleptics; it may increase the risk of developing seizures.
Avoid use of evening primrose oil in pregnancy and lactation. It may interact with the following medications: anticoagulants, antidepressants, anti-seizure medicines, blood pressure medicines, anticonvulsants, aspirin, hypoglycemic medications, phenothiazines, anaesthetics etc.
Store evening primrose oil products away from the sunlight in light-resistant containers to avoid degradation.
Please consult a health practitioner before taking EPO supplements.
Evening primrose oil primarily benefits in diabetic neuropathy by providing omega-3 fatty acid: gamma-linolenic acid. It improves blood flow, reduces metabolic abnormalities and restores nerve function.
It can even assist in nerve regeneration. The combination of GLA and ALA is proven to relieve neuropathic pain.
These findings are restricted to animal models. Very few human studies have been conducted on EPO and peripheral neuropathy.
Further research in the form of robust clinical trials must be conducted to observe the effect of oral evening primrose oil supplement in peripheral neuropathy (both diabetic and non-diabetic). Also its synergy with Alpha lipoic acid must be studied, since ALA is beneficial for peripheral neuropathy.
There is not enough research available at this moment to recommend the use of evening primrose oil for peripheral neuropathy. Do browse the website for other alternative natural care options.