Nutraceutical manufacturers targeting cognitive health benefits often turn to ingredients which can attenuate chronic, low-grade inflammation, and are known to cross the blood-brain barrier, as the presence of pro-inflammatory compounds is associated with neuronal damage. Because of the capacity of omega-3s to modulate inflammatory responses, as well as DHA’s ability to cross the blood-brain barrier, researchers theorize that omega-3s may have the potential to attenuate neuronal inflammation, possibly reducing risk factors for age-related cognitive decline.
 
“Neuroinflammation constitutes a normal part of the brain immune response,” the authors of the study said. “It remains a crucial mechanism of defense against pathogens and is involved in response to injury as well as wound healing […] however, a sustained and uncontrolled production of proinflammatory factors together with microglial activation contribute to the onset of chronic low-grade inflammation, leading to neuronal damage, as observed in neurodegenerative diseases and aging.”

However, new evidence suggests that fish hydrolysate, which contains trace amounts of DHA compared to its purified form, might significantly decrease a greater number of markers of neuroinflammation compared to DHA alone. 
 
In a preclinical study published in the journal Nutrients, researchers investigated the effect of both a fish hydrolysate and DHA supplementation on lipopolysaccharide (LPS)-induced neuroinflammation in mice. Over the course of 18 days, mice were supplemented with a fish hydrolysate, and researchers found through subsequent hippocampal samples that it decreased the proinflammatory cytokines IL-6, IL-1B, and TNF-a, whereas DHA supplementation only reduced the expression of IL-6.
 
Furthermore, the researchers found that the decline in proinflammatory cytokines was associated with an increase in the protein expression of IKB, and to a modulation of microglial (type of cells in the central nervous system) activation markers in the hippocampus. This led the researchers to conclude that dietary supplementation may counteract neuroinflammation through the two aforementioned mechanisms of action.
 
“These results are particularly of interest since the fish hydrolysate allowed a faster immune response compared to a supplementation with 100 times more DHA, described as the efficient dose in literature. Furthermore, the fish hydrolysate was obtained through the valorization of marine byproducts in a context of sustainable development. Thus, it remains an innovative and good candidate for the prevention of inflammation and notably in the case of neurodegenerative pathologies, which are characterized by a chronic low-grade inflammation,” the authors concluded.
 
However, further investigations are needed to decipher the individual role of fish hydrolysate peptides versus DHA alone, the authors said, in order to yield more preclinical evidence.