Review outlines astaxanthin's cognitive health benefits

Researchers from Edge Hill University in the UK explored the effects of astaxanthin, a potent antioxidant, on cognitive function and neurodegeneration in human populations and samples to decipher "the merit and credibility of the research findings and subsequently their potential as a basis for therapeutic use."

Oxidative stress, which is a key contributing factor in neurodegeneration, cognitive aging, cognitive decline and diminished cognitive longevity, has been shown to benefit from antioxidants such as astaxanthin.

"Over recent years, more research has been published pertaining to the benefits of astaxanthin," Callum Queen, a co-author on the study, told NutraIngredients. “With this increased research interest, the exploration of astaxanthin has moved to human-based studies [...]. Prior to this review, there had been no critical review outlining how astaxanthin impacts cognition and neurodegeneration in only human samples [...]. This provided a strong rationale for the research."

"Based on the review, I believe astaxanthin has the potential to aid in cognitive health holistically as well as specific sub areas of the overarching term—such as neurodegeneration," he added. "I do however also believe that these recommendations be taken with the acknowledgement of the need for further research."

A potent antioxidant​

Found in algae, salmon, shrimp and krill, natural astaxanthin (AST) is one of the most potent carotenoids​  and known for its unique pink color.

Studies suggest that it has greater oxygen radical absorbance capability than other antioxidants​ and that its specific properties allow it to maintain the structure and integrity of cell membranes, facilitating improvement in gene expression and immune system function​.

Its benefits, particularly in human samples and tissue, have only been explored more thoroughly in recent years​, driven by the current focus on dietary supplements for the general population​.

To explore the impact of astaxanthin on cognition and neurodegeneration in their entirety, the researchers reviewed its effects as part of a compound, as well as the literature describing its impact on indirect factors related to cognition, such as mental and physical fatigue.

Cognitive performance benefits​

Research shows that astaxanthin has positive effects on neuronal apoptosis—also known as 'cell death'.​ Neuronal apoptosis is required for processes like immune system function and cell turnover​. However, under negative and uncontrolled pathological conditions, it is thought to contribute to some cognitive diseases.

In terms of neuroprotection, the authors noted that conclusions can be drawn from findings associated with neurodegenerative diseases like Parkinson’s disease (PD) and Alzheimer’s disease (AD)​.

Research on the protective effects of astaxanthin on apoptosis in the SH-SY5Y human neuroblastoma cell line​—a cell line associated with PD (following appropriate treatment)—suggests it could benefit the condition. This is thought to be the result of astaxanthin’s ability to both protect mitochondria and capitalize on its antioxidant potential​.

There are many animal-based studies demonstrating the potentially positive effect of astaxanthin on Alzheimer’s disease​, however, there is minimal evidence to substantiate the claim in humans.

Astaxanthin may also have preventative capabilities for some forms of dementia, stemming from its effects on the condition’s underlying mechanisms. The researchers noted that to substantiate this claim, research should be done using people with an AD diagnosis. They also noted that astaxanthin elicits cognitive performance benefits when taken as part of a supplement blend containing additional key ingredients.

In conclusion, the study suggests that astaxanthin has the potential to improve cognitive function, facilitate neuroprotection and slow neurodegeneration in certain contexts.

"This claim is made based on the established positive effects of AST on different branches of memory and response time, as well as the implications of work utilizing biomarkers in human populations,” the researchers wrote, highlighting benefits in “primarily subdivisions of episodic memory, response time and working memory."

They did however note that studies supporting astaxanthin as a supplement for cognitive improvement often use only a particular age demographic, broad cognitive tests or a small sample size without appropriate research design, indicating a need for more robust studies.

“The findings at a surface level were unsurprising as astaxanthin was shown to be beneficial for cognitive function and neurodegeneration in given cases,” Queen saiid. "The work did however highlight the need for further research, which should investigate the differences in effectiveness of astaxanthin. Areas for consideration include the type of cognitive function being assessed and the efficacy of the assessment, the specific supplemental strategy for optimum use and the impact of the specific population being targeted.”

Source: Nutrients​ 2024​, 16​(6), 826
doi: 10.3390/nu16060826​
“The Effects of Astaxanthin on Cognitive Function and Neurodegeneration in Humans: A Critical Review.”
Authors: Callum James et al.