The famously spicy sushi condiment only makes your sinuses feel clear. From Think Wasabi Clears Your Sinuses? Think Again:
U.S. researchers found that eating wasabi appeared to increase congestion in a small group of healthy volunteers, despite the fact that participants said they thought that the spice had cleared their nasal passages.‘Actually, wasabi is a congestant,’ study author Dr. David S. Cameron told Reuters Health. ‘It makes the space of your nasal passages smaller, but it makes you feel more open.’
Cameron explained that wasabi probably clogs up sinuses by increasing blood flow to the lining of the nose. That extra blood takes up space, he said, which constricts the nasal passageway.
Wasabi may make the nose feel more open, Cameron noted, by causing changes that increase the cooling effect of air breathed through the nose, or by stimulating flaring of the nostrils, which enables air to flow more easily though the nose.
Wasabi does have some legimate uses though:
While wasabi may not work as a decongestant, previous research has suggested that it is not without other health benefits. For instance, lab research shows that wasabi may inhibit the growth of cancer cells in test tubes, prevent platelets from forming blood clots, and may even fight asthma or cavities. And, appropriately for a condiment used to season raw fish, wasabi has antimicrobial properties.