In multiple sclerosis (MS), myelin — the "coating" that protects nerve cells — is wrongly attacked and damaged by the immune system.
The causes that trigger this condition remain unclear, and there is currently no cure for it. Current treatments focus on symptom management.
This being the case, researchers seek to find out which factors could reduce the risk of developing MS. Recently, Dr. Annette Langer-Gould — who works at Kaiser Permanente Southern California in Pasadena — explored the relevance of certain nutritional choices in the likelihood of developing this condition.
Dr. Langer-Gould wanted to explore whether there was any association between a high intake of omega-3 — obtained by adhering to a fish-rich diet and taking fish oil supplements — and a reduced risk of MS.
"We are increasingly recognizing that MS is not only a chronic inflammatory disease of the central nervous system," Dr. Langer-Gould explained to Medical News Today, "but also often leads to diffuse neurodegeneration [neural degradation spread to various parts of the CNS]."
"While the cause is not known," she continued, "the rising prevalence of MS has led to increased interest in identifying modifiable risk factors including diet."
She is due to present the study's findings at the American Academy of Neurology's 70th Annual Meeting, which will be held in Los Angeles, CA.
'Omega-3 is neuroprotective'
Dr. Langer-Gould took special interest in the role played by dietary omega-3 and its potential link to reduced risk for MS, because this fatty acid has been tied to a wealth of health benefits. Also, omega-3 deficiency seems to play a role in the advent of neurological conditions.
"Fish or other seafood consumption," she told us, "is particularly interesting because it is the main determinant of circulating and tissue levels of omega-3 polyunsaturated fatty acids (omega-3 PUFAs)."
"Omega-3 PUFAs have been shown to be neuroprotective during aging and suppress MS-related inflammation through multiple mechanisms in cell cultures and animal models. This provides at least two biologically plausible mechanisms whereby higher omega-3 PUFA intake and biosynthesis could protect against development of MS."
Dr. Annette Langer-Gould
In the new study, the team worked with 1,153 participants — aged 36, on average — approximately half of whom had a diagnosis of clinically isolated syndrome or MS. Dr. Langer-Gould and team analyzed the participants' dietary habits, focusing on their intake of fish and fish oil dietary supplements.
Depending on how much fish they ate on a regular basis, the participants' diets were catergorized as either:
- "high-intake," which was defined as one serving of fish per week (or one to three servings per month) plus daily fish oil supplement intake
- "low-intake," which was defined as fewer than one serving of fish per month with no fish oil supplement intake
Some of the fish or seafood that the participants reported eating were salmon, tuna, and shrimp.
After analyzing the data provided by the participants, the scientists found that a regularly high intake of fish was linked to a 45 percent lower risk of clinically isolated syndrome or MS when compared with a low intake of fish.
Of those with an MS diagnosis, 180 reported eating fish regularly and taking fish oil supplements, whereas 251 of the overall healthy control participants declared the same.
"This study provides more evidence that a diet rich in fish and omega-3 PUFAs has health benefits," noted Dr. Langer-Gould. "In addition to promoting improved cardiovascular health, a high-fish/seafood diet may also reduce the risk of developing MS."
Further studies aim to 'replicate findings'
The researchers also examined 13 variations of a gene cluster that is associated with the regulation of fatty acid levels in the body. They discovered that two of these variations seemed to be linked to a decreased risk of developing MS — independently from any benefits potentially provided by a high intake of fish.
According to the team, this suggests that individual genetic makeup plays an important role in the regulation of nutrient levels that may influence the risk of MS.
Dr. Langer-Gould explained that the study's "findings could certainly lead to lifestyle modification interventions that could improve overall health for MS patients and perhaps prevent MS in their offspring."
Nevertheless, she cautions that these results do not indicate a clear "cause and effect" relationship, and that further studies should aim to clarify the role played by omega-3 fatty acids in the context of MS prevention.
"The next step," Dr. Langer-Gould explained to MNT, "is [to] try and replicate our findings in another dataset."
"If our findings are confirmed," she added, "it will be important to determine whether the protective effective is mediated by the anti-inflammatory, metabolic, and/or neuroprotective actions of omega-3 fatty acids and whether fish/fish oil consumption could improve MS prognosis."