The real wasabi comes from the rhizome of wasabia japonica and western wasabi is horseradish processed with Chinese mustard and green food coloring.
Let me give you a word of caution regarding the green paste that is readily available in supermarkets and even in restaurants serving Japanese food. Let me differentiate the “real” wasabi from what they now call as “western wasabi”.
The real wasabi comes from the root-like stem (rhizome) of wasabia japonica. It grows in the moist and shady areas of Japan and is being cultivated in North America. When freshly grated, real wasabi forms a coarsely textured and light green paste that is both flavorful and pungent.
Most wasabi manufacturers, however, use a root known as horseradish, which is also called as the western wasabi. They combine it with Chinese mustard and green food coloring. It may give you the same sort of burning sensation as the Japanese wasabi, but not the same color and flavor. It may make your eyes water and can clear sinuses, but has not significant benefits since much of it is artificially colored. This type of wasabi was influenced by western influx which introduced “western wasabi” to Japan in the 19th century. Since it grows faster, bigger and cheaper than the “real wasabi”, it is but natural businesses went for this for profitability/practicality.
Those familiar with the “real wasabi” may lift their eyebrows and even comment that ‘western wasabi” lacks good taste. The equality of these two varieties can be explained in a sense that one wasabi may best compliment fish while the other maybe had a better partner for other Japanese cuisine.
Even if we are already in the 21st century, wasabi’s popularity to helping one’s health condition never ceased. In fact, even science has conducted empirical studies on the health benefits of wasabi. They have discovered the biochemically active Isithiocyanates (ITCs), which also caused the pungency of wasabi, are probably the reason for the medicinal benefits of wasabi. Research suggests that ITCs have anti-cancer, anti-inflammatory, antiplatelet and anti-microbial effects, but these benefits have been reported in laboratory and a few animal studies.