Omega-3 fatty acids are known for a range of health benefits, from promoting brain and heart health to reducing inflammation and protection against several chronic conditions.

In a new study, researchers found that omega-3 acids, especially the type found in foods like flaxseeds, walnuts, chia seeds, canola oil and soybean oil, can slow down the progression of amyotrophic lateral sclerosis (ALS).

It is a debilitating nervous system disease that gradually worsens over time and can be fatal. The condition results in a loss of muscle control and affects the nerve cells in the brain and spinal cord. It is also known as Lou Gehrig's disease after the baseball player who was diagnosed with it.

The initial symptoms of the disease include muscle weakness, difficulty in walking and hand movements. The symptoms can slowly progress to difficulties with chewing, swallowing, speaking and breathing.

The exact cause of ALS is not known. However, around 10% of people get it from a risk gene passed down from a family member. It is estimated that more than 32,000 people in the U.S. live with the condition.

In the latest study, researchers from Harvard T.H. Chan School of Public Health in Massachusetts evaluated 449 people living with ALS in a clinical trial. The team assessed the severity of their symptoms, the progression of their disease, along with the levels of omega-3 fatty acids in their blood, for 18 months.

The study suggested that alpha-linolenic acid (ALA), a type of omega-3 found in plants, is particularly beneficial in slowing the progression of ALS. The participants with the highest levels of ALA had a 50% reduced risk of death during the study period compared to those with the lowest levels of ALA.

Researchers also found a reduction in death risk in participants who had eicosapentaenoic acid, the type of omega-3 fatty acid found in fatty fish and fish oil, and linoleic acid found in vegetable oils, nuts and seeds.

A previous study conducted by the same team suggested that a diet high in ALA and higher blood levels of the nutrient could reduce the risk of developing the condition.

"In this study, we found that among people living with ALS, higher blood levels of ALA were also associated with a slower disease progression and a lower risk of death within the study period. These findings, along with our previous research suggest that this fatty acid may have neuroprotective effects that could benefit people with ALS," said Kjetil Bjornevik, the lead author of the study.