Omega-3s protect and accelerate healing of peripheral nerves

Omega-3s could be valuable allies against peripheral nerve damage. Research on animal models and preliminary clinical studies suggest that these fats, known for their anti-inflammatory properties and importance in the nervous system, might even promote the healing of already damaged peripheral nerves.

If confirmed, this property of Omega-3s could help manage conditions faced by those living with diseases such as diabetes, whose complications can include problems with these nervous system components.

The role of Omega-3s in nervous tissue

Omega-3s (in particular, the "long-chain" types: EPA - eicosapentaenoic acid - and DHA - docosahexaenoic acid) are important components of nerve cell membranes, regulating their properties.

Besides ensuring the multiplication and differentiation of neurons, they also help neurons correctly use neurotransmitters (molecules responsible for transmitting nerve impulses).

Cell membranes of the brain and retina are particularly rich in DHA, a nutrient necessary for the development and proper functioning of vision and brain. Moreover, a derivative of DHA – neuroprotectin D-1 (NPD-1) – protects nerve structures by reducing inflammation and signals that induce programmed cell death caused by oxidative stress.

DHA and NPD-1 have been associated with possible benefits in neurodegenerative conditions of the central and peripheral nervous systems. More generally, long-chain Omega-3s are precursors of a series of anti-inflammatory and neuroprotective molecules, and various studies over the years have shown their benefits against several neurological disorders, including acute trauma.

Experts believe these fats’ properties are useful in the prevention, control, and treatment of psychiatric disorders such as:

• depression;
• bipolar disorder;
• neurodegenerative diseases (such as Alzheimer’s).

Damaged nerves: it’s not just about pain

Focusing on nerve damage, it is important to consider that pain is not the only issue faced by those with nerve trauma. Other possible consequences include feelings of weakness or even muscle paralysis.

Fortunately, peripheral nerves (those located outside the brain and spinal cord) have the ability to regenerate. Moreover, targeted medical techniques can aid functional recovery.

Unfortunately, except for milder injuries, healing from such trauma is usually incomplete. Strategies that promote healing or help prevent damage would therefore be welcomed.

Omega-3 supplements: help also for peripheral nerve trauma

One of the first indications of Omega-3s' possible effectiveness in preventing peripheral nerve damage and aiding their regeneration after trauma came from a study led by Adina Michael-Titus at Queen Mary University of London (UK), published in the Journal of Neuroscience in 2012.

Michael-Titus and colleagues simulated trauma to nerve cells in mice genetically modified (fat-1 gene expression) to accumulate higher-than-normal Omega-3 levels. They damaged peripheral nerves by stretching or depriving them of oxygen, then measured cell death levels. They found that high Omega-3 levels protect neurons from both types of damage.

A second experiment, damaging the sciatic nerve in mice, showed that animals with higher levels of these fatty acids recover nerve function more rapidly.

Finally, fat-1 expressing mice were also protected from muscle atrophy caused by neurological damage.

These mouse experiments were confirmed by analyzing expression of damage markers. Thus, years ago, both in vivo and in vitro studies suggested these nutrients might be useful for treating nerve damage outside the brain and spinal cord.

This hypothesis was further strengthened by later studies, such as one published in 2017 in Frontiers in Pharmacology by a team led by Ana Miranda at the Federal University of Rio de Janeiro (Brazil).

In experiments on mice, Miranda and collaborators induced neuropathic pain associated with peripheral nerve damage by partial ligation of the sciatic nerve. Animals were then given 4, 6, or 2.3 g of concentrated fish oil (source of long-chain Omega-3) for 10 days.

It emerged that the lowest dose, taken for 5 days, was enough to prevent symptoms following the ligation and the expression of inflammatory molecules.

“These results,” the authors concluded, “indicate the regenerative and possibly protective properties of combined oral EPA and DHA intake after peripheral nerve damage, as well as their anti-neuroinflammatory activity, highlighting promising therapeutic effects of Omega-3s in treating neuropathic pain.”

More recently, clinical studies have confirmed that effects seen in animal models may also apply to humans.

For example, a 2021 study published in the Journal of Diabetes and its Complications involved Canadian researchers who gave marine oil containing Omega-3s (a daily total of 750 mg EPA, 1020 mg DHA, and 560 mg DPA - docosapentaenoic acid) to 40 type 1 diabetes patients, including 23 with distal symmetric polyneuropathy (the most frequent chronic complication of diabetes, characterized by damage to multiple nerves in different body parts).

Measuring blood Omega-3 levels at study start and 4, 8, and 12 months after starting oil intake, the authors concluded that low DHA levels are associated with distal symmetric polyneuropathy and that “higher baseline Omega-3 levels are associated with greater nerve regeneration.” 

Specifically:

• DHA levels were lower in participants with polyneuropathy;
• after 12 months of intake, EPA, DPA, and DHA levels increased on average by 185%, 29%, and 79% respectively;
• after 12 months of treatment, corneal nerve length also increased on average by 29%;
• higher baseline levels of DHA, DPA, or total Omega-3 were associated with greater changes in corneal nerve length.

Two other small studies suggest that taking EPA and DHA supplements during chemotherapy may reduce the incidence of treatment-induced neuropathy.

Omega-3 to protect nerves from trauma consequences

These and other data published in scientific literature suggest the usefulness of Omega-3s in protecting damaged nerve cells and accelerating the healing of peripheral nerves after trauma.

Further research may better clarify the protective role of Omega-3s on human nerves.

Discover all the latest on Omega-3 benefits for the nervous system by continuing to read the Omegor Blog!

References

Britten-Jones AC, Calder G, Busija L, Kamel J, Roberts LJ, MacIsaac RJ, Downie LE. Omega‐3 fatty acid supplementation for distal symmetrical peripheral neuropathy in adults with diabetes mellitus. Cochrane Database Syst Rev. 2023 Jul 6;2023(7):CD014623. doi: 10.1002/14651858.CD014623

Gladman SJ, Huang W, Lim SN, Dyall SC, Boddy S, Kang JX, Knight MM, Priestley JV, Michael-Titus AT. Improved outcome after peripheral nerve injury in mice with increased levels of endogenous ω-3 polyunsaturated fatty acids. J Neurosci. 2012 Jan 11;32(2):563-71. doi: 10.1523/JNEUROSCI.3371-11.2012

Lewis EJH, Lovblom LE, Cisbani G, Chen DK, Bazinet RP, Wolever TMS, Perkins BA, Bril V. Baseline omega-3 level is associated with nerve regeneration following 12-months of omega-3 nutrition therapy in patients with type 1 diabetes. J Diabetes Complications. 2021 Mar;35(3):107798. doi: 10.1016/j.jdiacomp.2020.107798

Silva RV, Oliveira JT, Santos BLR, Dias FC, Martinez AMB, Lima CKF, Miranda ALP. Long-Chain Omega-3 Fatty Acids Supplementation Accelerates Nerve Regeneration and Prevents Neuropathic Pain Behavior in Mice. Front Pharmacol. 2017 Oct 17;8:723. doi: 10.3389/fphar.2017.00723

Zhang AC, De Silva MEH, MacIsaac RJ, Roberts L, Kamel J, Craig JP, Busija L, Downie LE. Omega-3 polyunsaturated fatty acid oral supplements for improving peripheral nerve health: a systematic review and meta-analysis. Nutr Rev. 2020 Apr 1;78(4):323-341. doi: 10.1093/nutrit/nuz054