The benefits of fish oil have been touted for a variety of health conditions – including heart disease, stroke and arthritis. Now a new study suggests that a derivative of DHA (docosahexaenoic acid), a main ingredient in fish oil, can relieve and prevent neuropathic pain.
The finding raises the possibility of developing a new pain medication that is non-addictive, effective at low doses, and has no apparent side effects.
Researchers at Duke University focused on a bioactive lipid produced by cells in response to external stimuli. The compound, known as neuroprotectin D1=protectin D1 (NPD1=PD1), is present in human white blood cells, and was first identified for its ability to reduce abdominal and brain inflammation.
“These compounds are derived from omega-3 fatty acids found in fish oil, but are 1,000 times more potent than their precursors in reducing inflammation,” said Ru-Rong Ji, professor of anesthesiology and neurobiology at Duke University Medical Center and principal investigator of the study. The results appear in the Annals of Neurology.
Using laboratory models of nerve injuries in mice, Ji and his team treated the animals with chemically-synthesized NPD1=PD1 to see if the lipid could relieve the pain symptoms associated with post-surgical nerve trauma.
Not only did the compound alleviate the pain, it also reduced nerve swelling from the injuries.
Researchers say the analgesic effect of NPD1=PD1 is caused by its ability to inhibit the production of cytokines and chemokines, the small signaling molecules that attract inflammatory white blood cells. NPD1=PD1 also reduced neuron firing so the mice felt less pain, protecting their nerve cells from further damage.
Although the clinical potential has yet to be fully explored, Ji said the discovery does show promise.
“Chronic pain resulting from major medical procedures such as amputation, chest and breast surgery is a serious problem,” said Ji. “We hope to test this compound in clinical trials.”
Current treatment for neuropathic pain includes the drug gabapentin (Neurontin) and various opioid painkillers, which can lead to addiction, destruction of sensory nerves and other side effects.
However, the mice receiving NPD1=PD1 did not show any signs of physical dependence or enhanced tolerance toward the lipid, which relieved neuropathic pain at very low doses.
“DHA is very inexpensive, and can be converted to NPD1 by an aspirin-triggered pathway,” said Ji, with the ultimate goal to develop a safer approach to managing chronic pain.
Fish oil is rich in omega-3 fatty acids, which are known to reduce inflammation. Studies also suggest that fish oil may provide some benefits to a range of diseases such as cancer, asthma, depression, cardiovascular disease, ADHD and rheumatoid arthritis.
A recent study also found that young adults who take fish oil supplements significantly improved their memory.
But doctors warn that taking high doses of fish oil can also inhibit the immune system’s activity, reducing the body’s ability to fight infection. They recommend that people only take high doses of fish oil while under medical supervision.