Omega-3s protect and accelerate peripheral nerve healing

Omega-3s could be valuable allies against peripheral nerve damage. Suggesting this are animal model research and preliminary clinical studies that these fats, known for their anti-inflammatory properties and their importance at the level of the nervous system, could even promote the healing of already damaged peripheral nerves.

If verified, this property of Omega-3s could help manage situations such as those that people living with conditions such as diabetes may have to deal with, whose possible complications include problems with these components of the nervous system.

The role of omega-3s in nervous tissue

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

In addition to ensuring the multiplication and differentiation of neurons, they also help them properly use neurotransmitters (the molecules responsible for nerve impulse transmission).

The 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. Not only that, one of its derivatives-neuroprotectin D-1 (NPD-1)-protects nerve structures by attenuating inflammation and signals that induce oxidative stress-induced programmed cell death.

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

According to experts, the properties of these fats would be 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 a matter of pain

Focusing on the case of damage to nerve structures, it is important to keep in mind that pain is not the only problem that those who suffer a nerve injury have to deal with. Other possible consequences of damage to nerve structures may be a feeling of weakness or, even, muscle paralysis.

Fortunately, peripheral nerves (which are those located outside the brain and spinal cord) have the ability to regenerate. Not only that, targeted medical techniques can help regain function.

Unfortunately, however, with the exception of the mildest damage, recovery from this type of trauma is generally not complete. Any strategies that promote it or help avoid damage would therefore be welcome.

Omega-3 supplements: also an aid for peripheral nerve injury

One of the first clues to the possible effectiveness of Omega-3s in preventing peripheral nerve damage and regeneration after trauma came from a study coordinated by Adina Michael-Titus of Queen Mary University of London, UK, published in the Journal of Neuroscience in 2012.

Michael-Titus and colleagues simulated trauma in the nerve cells of mice that are able to accumulate higher than normal levels of Omega-3 due to fat-1 gene expression. Specifically, the researchers damaged peripheral nerves by stretching or depriving them of oxygen and then assessed levels of cell death. They found that high levels of Omega-3 protected neurons from both types of damage.

A second experiment, in which scientists damaged the sciatic nerve of mice, revealed that animals that accumulated larger amounts of these fatty acids were able to recover nerve function more quickly.

Finally, mice expressing fat-1 were also found to be protected from muscle atrophy that can be caused by neurological damage.

The results of the experiments in mice were confirmed by analyzing the expression of certain damage markers. Thus, already several years ago both in vivo studies and in vitro experiments suggested that these nutrients might be useful in treating nerve damage located outside the brain and spinal cord.

This hypothesis has been further strengthened by the results of subsequent studies, such as one published in Frontiers in Pharmacology in 2017 by a group of researchers coordinated by Ana Miranda of the Universidade Federal do Rio de Janeiro (Brazil).

In experiments in mice, Miranda and coworkers induced the neuropathic pain typically associated with peripheral nerve damage by partial ligation of the sciatic nerve. The animals were then given 4.6 or 2.3 g of concentrated fish oil (a source of long-chain Omega 3) for 10 days.

It emerged that the lowest dosage, taken for 5 days, was sufficient to prevent the symptoms resulting from ligation and the expression of inflammatory molecules.

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

More recently, clinical studies have confirmed that the effects that emerged in animal model experiments could also apply to humans.

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

By measuring the participants' blood Omega 3 levels at the beginning of the study and 4, 8, and 12 months after they began taking the oil, the authors concluded that low DHA levels are associated with distal symmetric polyneuropathy and that "higher basal Omega 3 levels are associated with increased nerve regeneration."

Indeed:

• DHA levels were lower in participants with polyneuropathy;
• after 12 months of intake, EPA, DPA and DHA levels had increased, on average, by 185%, 29% and 79%;
• after 12 months of treatment, corneal nerve length had also increased (on average, by 29%);
• Higher basal levels of DHA, DPA or total Omega 3 were associated with greater change in corneal nerve length.

Two other small studies suggest that taking an EPA and DHA supplement during chemotherapy could reduce the incidence of cancer treatment-induced neuropathy.

Omega-3 to protect nerves from the consequences of trauma

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

Further research may better elucidate the protective role of Omega-3s toward human nerves.

Learn all about the benefits of Omega-3s for the nervous system by continuing to read the Omegor Blog!

Bibliographical 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