Wasabi Linked To 'Substantial' Boost In Memory, Japanese Study Finds

Researchers at Tohoku University in Japan found that wasabi improves both short- and long-term memory. CBS News reports: Rui Nouchi, the study's lead researcher and an associate professor at the school's Institute of Development, Aging and Cancer, told CBS News the results, while based on a limited sample of subjects without preexisting health conditions, exceeded their expectations. "We knew from earlier animal studies that wasabi conferred health benefits," he said in an interview from his office in northeast Japan. "But what really surprised us was the dramatic change. The improvement was really substantial." The main active component of Japanese wasabi is a biochemical called 6-MSITC, a known antioxidant and anti-inflammatory known to exist in only trace amounts elsewhere throughout the plant kingdom, Nouchi said. The double-blind, randomized study involved 72 healthy subjects, aged 60 to 80. Half of them took 100 milligrams of wasabi extract at bedtime, with the rest receiving a placebo. After three months, the treated group registered "significant" boosts in two aspects of cognition, working (short-term) memory, and the longer-lasting episodic memory, based on standardized assessments for language skills, concentration and ability to carry out simple tasks. No improvement was seen in other areas of cognition, such as inhibitory control (the ability to stay focused), executive function or processing speed. Subjects who received the wasabi treatment saw their episodic memory scores jump an average of 18%, Nouchi said, and scored on average 14% higher than the placebo group overall. The researchers theorized that 6-MSITC reduces inflammation and oxidant levels in the hippocampus, the area of the brain responsible for memory function, and boosts neural plasticity. Compared with the control group, the study said, subjects dosed with wasabi "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." But here's the rub: most of the "wasabi" you order at sushi restaurants is made of ordinary white horseradish, dyed green. "Genuine wasabi must be consumed fresh, with the stubbly rhizome, or stem of the plant, grated tableside just before eating," notes the report. "On the plus side, just a small dab offers the same benefits as the capsule supplements used in the Tohoku study, or 0.8 milligrams of 6-MSITC." The study has been published in the journal Nutrients.

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