Influenza, commonly referred to as the flu, is a contagious infection of the respiratory system that is caused by influenza viruses, including types A, B and C.
Flu viruses are transmitted through the air in tiny droplets when an infected person coughs, sneezes or talks. Individuals are then exposed to the virus through inhalation or by contact with objects such as telephones, door handles, railings or computer keyboards. The virus may cause infection when it enters the eyes, nose or mouth.
In general, the flu is more debilitating than the common cold. Symptoms such as fever, body ache, extreme fatigue (tiredness) and dry cough are often more severe in flu than in the common cold.
A study conducted by researchers in Japan examined wasabi (Wasabia japonica), which has traditionally been used as a spice in Japanese foods for its pungent taste and flavor.
The wasabi roots (or rhizomes) and its winter leaves are used as a spice and for processed foods such as pickled wasabi. Because the summer leaves are much larger than winter leaves, the researchers investigated the summer leaves, which would otherwise be discarded.
Previous studies have shown the antiviral activity of the winter leaves. The researchers found that the extracts of summer leaves exhibited the same anti-influenza virus activity as winter leaves and showed a stronger activity than stems, roots and rhizomes.
The study authors concluded that a potent anti-influenza virus activity was discovered in summer leaves of Japanese wasabi; the extracts inhibited influenza virus replication regardless of the hemagglutinin antigen type. Hemagglutinin or haemagglutinin is a protein found on the surface of the influenza viruses responsible for binding the virus to the cell that is being infected.
In a related study, researchers from China examined Elsholtzia rugulosa, a common Chinese herb widely used in the treatment of cold and fever.
They found five active constituents, all flavonoids, possessed anti-influenza virus activity. The flavonoids apigenin and luteolin exhibited the highest activities against the influenza virus.
Finally, another Japanese study evaluated the anti-influenza virus activity of 50 percent ethanol extract of the fruit of Chaenomeles sinensis K(OEHNE), which is widely used as a traditional Chinese medicine to treat throat diseases.
Type A and B influenza viruses were exposed to the extract at various concentrations for one hour at room temperature; then the plaque titers of the treated viruses were determined.
The study found that treatment with the extract at concentrations greater than 5 milligrams/milliliter reduced the plaque titers of both viruses to less than 10 percent compared with untreated viruses. The treatment inhibited viral activity as well.
The authors concluded that high molecular weight polyphenols in the fruits of C. sinensis may neutralize the influenza virus.
Every year in the United States, on average 5-20 percent of the population gets the flu and more than 200,000 people are hospitalized from flu complications, such as dehydration, high fever and extreme fatigue. About 36,000 people die from flu every year.
Some patients, such as older people, young children and people with certain health conditions that lower immunity, including cancer, human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS), are at high risk for serious flu complications.
Children are two to three times more likely than adults to get sick with the flu. Children may also frequently spread the virus to others due to bad hygiene, such as sneezing without covering the nose and mouth.
Treatment for the flu includes bed rest and plenty of fluids, along with symptomatic treatment such as drugs to fight viral infections, reduce fever and help with sore throat and cough. Annual flu vaccinations may help reduce the risks of flu infection. For more information, please visit Natural Standard’s Medical Conditions database.