Peripheral neuropathy affects approximately 2.4% of the population, increasing to 8% in older populations. It is associated with a range of conditions, including diabetes, chronic alcoholism, inflammatory conditions, nutritional deficiencies, autoimmune diseases, Lyme disease, and other chronic infections, and certain medications and inherited conditions. The underlying contributing factors to the development of neuropathy depend on the cause, but it generally involves degeneration of some part of the neurons, such as the myelin sheath and the nerve axon.
Gamma-linolenic acid (GLA) is an omega-6 polyunsaturated fatty acid that can be derived from the oil of evening primrose seeds, blackcurrants, and borage seeds. The body converts it from linoleic acid and uses it as part of the structural phospholipids in the neural cell membranes, making it necessary for maintaining healthy nerve membrane structure and function. It also promotes anti-inflammatory effects, both directly from its anti-inflammatory properties of the metabolites and indirectly through competition with pro-inflammatory arachidonic acid products. Due to the involvement of GLA in neural cells and anti-inflammatory mechanisms, it has been considered as potential support for neuropathy.
Another reason that supplementation of GLA may support neuropathy stems from the potential effect of diabetes, non-alcoholic fatty liver disease, cardiovascular disease, and inflammation on the activity of delta-5 and delta-6-desaturases. These enzymes convert linoleic acid into GLA. Consuming sources of GLA can overcome this impairment to provide adequate GLA to perform its actions, including its actions as part of the neural cell membranes.
Studies have demonstrated the potential of GLA for benefiting neuropathy. In one study on rats with induced hyperglycemia, a diet supplemented with evening primrose oil supported various aspects of neuropathy, including partially improving the density of intra-epidermal nerve fibers, thermal nociception, and cornea nerve fiber density and sensitivity, which can be a marker of neuropathy. This study also tested other oils and found that flaxseed had similar benefits, and fish oil worked even better.
In a randomized trial, 320 mg of GLA was compared to 600 mg of alpha-lipoic acid (ALA) for 12 weeks in patients with painful diabetic peripheral neuropathy. ALA has been found to significantly improve neuropathy symptoms and nerve conduction velocity. Both groups experienced significant reductions in Visual Analogue Scale (VAS) scores, a marker of pain severity, compared to baseline, with the scores for the GLA group changing from a mean of 5.26 at baseline to 2.94 after 12 weeks. There was no significant difference between the two groups with both treatments reducing the pain with no serious adverse events. This demonstrates that GLA may provide similar benefits as ALA for neuropathy.
Providing neural cells with the necessary nutrients for their structure and function with GLA may also help conditions associated with the degeneration of neurons, such as neuropathy. Therefore, adding fatty acids to a nutritional protocol for neuropathy may provide beneficial support.
By Kendra Whitmire, MS, CNS