About Six Weeks Ago I Noticed That Some Foods Had

About six weeks ago I noticed that some foods had a very bland taste like cardboard., in particular meat, bread and vegetables. Something was very astray with my taste buds and sensation. I've had a viral like upper respitory type infection, almost flu like for the past 8 weeks or so which seems to come and go but the loss of taste has defiantly got worse. I saw my dentist today thinking it may have been related to a dental issue as I have had gingivitis before and they were pretty happy with things there but did ask if I was using a mouth wash which I have been called Peroxyl that contains Hydrogen Peroxide... Could the regular use of this caused my partial loss of taste.. My naturapath thought it may be a zinc deficiency but has since ruled that out but has got me taking a Vinc and vitamin c mixture mixed with echinacea three times a day for the viral type flu conditions I'm experiencing. Very concerned about what's causing my loss of taste and any advise would be appreciated....