Wasabi (Eutrema japonicum) is a Japanese spice prepared from grinding the plant’s rhizome into a paste. Its main bioactive compound is 6-methylsulfinylhexyl isothiocyanate (6-MSITC), which has antioxidant, anti-inflammatory, anti-atherosclerotic, and anti-cancer effects based on preclinical studies. Only a few clinical trials of wasabi or 6-MSITC have been carried out. There has been one clinical trial in older people which showed that wasabi treatment improved a few cognitive functions, but not others. More clinical trials are needed to validate these findings. Wasabi is likely safe in amounts typically consumed in food, but large amounts may increase the risk of bleeding in people with bleeding disorders.
One randomized controlled trial has tested the effects of wasabi on cognitive function in healthy people. More clinical studies are needed to validate the findings. Our search identified:
Clinical data are limited with regards to the effects of wasabi on cognitive function. The largest study to date was a randomized placebo-controlled clinical trial of 72 healthy older adults over the age of 60, which showed that treatment with wasabi extract powder (containing 0.8 mg of 6-MSITC) every night for 12 weeks led to improvements in two types of memory (working memory and episodic memory) compared to placebo [1]. However, other cognitive functions were not significantly affected, including processing speed, attention, inhibition, reasoning, short-term memory, or visual-spatial performance.
In an open-label clinical trial of 15 patients with chronic fatigue syndrome, treatment with wasabi extract (containing 9.6 mg of 6-MSITC) per day for 12 weeks improved brain fog and the ability to find appropriate words [2]. Because of the open-label study design without a placebo control, placebo effects or practice effects cannot be ruled out.
No clinical trials have tested the efficacy of wasabi or 6-MSITC in patients with dementia. In a mouse model of Alzheimer’s disease, 6-MSITC treatment led to an attenuation of cognitive impairment and prevention of brain cell loss in the hippocampus [3]. However, these preliminary findings in mice have not been confirmed in humans.
Wasabi is considered safe in amounts typically consumed in food as condiment. At higher doses tested in clinical trials, wasabi treatment did not result in any serious adverse events, and body weight, blood tests, and urine tests were within reference values [4]. However, it is worth noting that ingesting excessive amounts of wasabi has been associated with an increased risk of bleeding and bruising in people with bleeding disorders and high amounts may interact with anti-coagulant or anti-platelet drugs [5]. A large amount of wasabi might also slow blood clotting and may increase bleeding during surgery, and therefore excessive consumption of wasabi should be avoided at least 2 weeks before surgery.
NOTE: This is not a comprehensive safety evaluation or complete list of potentially harmful drug interactions. It is important to discuss safety issues with your physician before taking any new supplement or medication.
Wasabi is available as a food condiment and is typically in paste or powder form. It is worth checking the food labels as wasabi packets or wasabi powder sold may not contain real wasabi and instead contain horseradish or other types of radishes with artificial green color added.
Full scientific report (PDF) on Cognitive Vitality Reports