Mims Natalia Reoutova
A randomized, double-blind, placebo-controlled clinical trial of Spirulina maxima extract has found significant improvements in visual learning and memory as well as enhanced vocabulary in over 60-year-olds with mild cognitive impairment (MCI).
Spirulina is a high-nutrient-value marine microalga, whose effects have been primarily studied in obesity and high blood pressure. [Eur Rev Med Pharmacol Sci 2016;20:150-156; Complement Ther Med 2019;47:102211-102217] In addition, Spirulina maxima 70 percent ethanol extract (SM70EE) has been shown to significantly improve cognitive outcomes through inhibiting memory loss in animal behaviour experiments. However, there has been no conclusive evidence of its benefits to human cognitive function. [Int J Mol Sci 2017;doi:10.3390/ijms18112401]
The present study sought to evaluate the effects of SM70EE on memory function in older adults and recruited 80 volunteers aged >60 years (mean age, 68 years; female, 74 percent) with MCI from Jeonbuk National University Hospital in Jeonju, Republic of Korea. The participants were randomized 1:1 to receive SM70EE or placebo capsules, taken three times daily after meals for 12 weeks. Compliance was >90 percent in both groups. [Nutrients 2022;doi:10.3390/nu14183714]
After 12 weeks, there were statistically significant differences between the SM70EE and placebo groups in terms of changes from baseline in visual learning (p=0.007), visual working memory (p=0.024) (both assessed by a computerized neurocognitive function test [CNT]) and vocabulary (p=0.043) (as assessed by Korean version of the Montreal Cognitive Assessment [MoCA-K]).
Visual working memory is reportedly more damaged than verbal working memory in patients with Alzheimer’s disease (AD), and patients with AD have lower visual working memory test results than healthy individuals. [Neuroscience 2007;150:346-356; Eur Radiol 2006;16:193-206] In addition, early symptoms of MCI are reportedly associated with impaired visuospatial working memory, which is due to shrinking of the hippocampus. [Neurology 2002;59:1594-1599] Furthermore, patients with early AD, such as those with MCI, can start having difficulties with phonetic conversion from visuospatial stimuli due to early atrophy of the fusiform gyrus, following the shrinkage of proximally located hippocampus. [J Cogn Neurosci 2010;22:2012-2026; Ear Hear 2014;35:366-374] “Therefore, the significant increase in vocabulary found in this study would appear to be due to visual memory improvement and related synergies,” explained the researchers.
The study did not report statistically significant differences between groups in any of the other tested variables, such as Korean mini-mental status examination scores, brain-derived neurotrophic factor and amyloid-β levels, and total antioxidant capacity. Importantly, no significant differences were observed between the two patient groups in terms of standard diagnostic laboratory tests (eg, liver enzyme and haemoglobin levels and blood cell counts), and no clinically significant adverse reactions were reported in either group.
“The significant findings of this study suggest that SM70EE supplementation in patients with MCI with memory disorders is safe and can play a role in prevention and management of AD,” concluded the researchers.