Wasabi found to boost brainpower in seniors

In a recent study published in the journal Nutrients, researchers examined the effect of wasabi, a traditional Japanese spice containing 6-Methylsulfinyl Hexyl Isothiocyanate (6-MSITC) with known anti-inflammatory and anti-oxidant properties, on the cognitive function of healthy adults above the age of 60 years.

Study: Benefits of Wasabi Supplements with 6-MSITC (6-Methylsulfinyl Hexyl Isothiocyanate) on Memory Functioning in Healthy Adults Aged 60 Years and Older: Evidence from a Double-Blinded Randomized Controlled Trial. Image Credit: Created with the assistance of DALL·E 

Background

A decline in cognitive function is a natural part of aging and profoundly impacts daily life and activities. Therefore, extensive research has focused on improving cognitive function and slowing the rate of age-related cognitive decline. Studies have reported that nutrition is one of the main factors influencing cognitive function in older adults, and specific diets such as the Mediterranean diet, consisting of large amounts of vegetables and fruits, can significantly improve memory functions and cognition.

Recent research also reports that the inclusion of herbs and spices, such as garlic and ginger, can improve cognition and memory functions in older adults, irrespective of the occurrence of dementia. Furthermore, spices and herbs can be easily incorporated into the diet as flavoring agents. Wasabi is a Japanese spice with various bioactive compounds such as 6-MSITC that are anti-oxidant and anti-inflammatory, and given that various studies have reported positive effects of anti-inflammatory and anti-oxidant compounds on cognitive performances in older adults, the benefits of wasabi need to be explored further.

About the study

In the present study, the researchers examined the impact of 12 weeks of wasabi intake in older adults. They hypothesized that 6-MSITC intake would result in improvements in working and episodic memory, inhibition performances, and processing speeds in older adults. They conducted a randomized, double-blinded, controlled trial where the testers and the participants were unaware of the hypothesis being tested, and the researchers, testers, and participants were blinded to the intervention.

The Frontal Assessment Battery and the Mini-Mental State Examination, along with the Geriatric Depression Scale, were used to screen the participants. Physical health reports and medical histories, including any food allergies, were verified during the recruitment process. Only right-handed individuals with no known food allergies and who were native Japanese speakers were included in the study.

The participants were required to be between 60 and 80 years of age, with no history of diabetes, mental disorders, cardiac disease, or cranial nerve disease. Individuals who were on medications that could interfere with their cognitive functioning or those who were heavy alcohol drinkers were excluded. The selected participants were, on average, 65 years old, and the group consisted mainly of females. They were randomly assigned to the 6-MSITC or placebo group.

The intervention was administered as a tablet, taken once a day just before bedtime. All the participants were asked to record their supplement intake, and the records were used to verify their adherence to the intervention. The wasabi tablet contained 100 milligrams of the wasabi extract, which has 0.8 milligrams of 6-MSITC.

The baseline cognitive assessments were conducted using Japanese versions of the Japanese Reading Ability Test, Mini-Mental State Examination, and Frontal Assessment Battery to assess general intelligence quotient, general cognitive functions, and frontal lobe functions, respectively. Post-intervention cognitive assessments were conducted using various standardized cognitive assessments such as symbol search, digit symbol coding, Stroop task, digit cancellation task, and colored progressive matrices task.

Results

The results reported that the group that was administered wasabi supplements containing 6-MSITC showed significantly better performances in episodic and working memory as compared to the group that was administered the placebo. However, no significant improvements were observed in any of the other cognitive domains.

The logical memory and face and second name tests showed that a 12-week-long administration of wasabi supplements showed improved verbal episodic memory performance as well as better performance in associating faces and names, which is often the major memory-related problem in older adults.

The potential mechanisms through which 6-MSITC could improve episodic and working memory included the reduction of inflammation and oxidant levels in the hippocampus, which plays a vital role in memory functions. The decreased oxidant and inflammatory levels in the brain could also improve brain functions such as neural plasticity.

Conclusions

Overall, the findings reported that wasabi supplements containing 6-MSITC improved episodic and working memory functions in older adults after a 12-week-long administration. However, other cognitive functions were not found to improve in association with the 6-MSITC supplementation.