For those of us who suffer from the irritating and uncomfortable symptoms of allergies such as sneezing, itching, watery eyes, blocked noses, and coughing there may not seem like there could ever be a brightside to the affliction but researchers say there might well be - and it's a biggie - a reduced risk of cancer.
So before you swallow another antihistamine pill or continue to use your natural allergy remedies you might want to read on.....
Researchers from Cornell University in the US looked at 646 studies on allergies and cancers published in medical journals over the past 50 years; ending up with the most comprehensive database yet available on allergies and cancer.
Professor of neurobiology and behaviour Paul Sherman and his team found that the number of studies concluding that allergies reduced the risk of cancer were double the number suggesting an increased risk. The types of cancer that appear to be reduced in those with allergies are those that involve organs that "interface directly with the external environment," according to Sherman. These cancers include colon, skin, bladder, mouth, throat, uterus and cervix, lung and cancers of the gastrointestinal tract.
In contrast, this relationship rarely exists, Sherman notes, between allergies and cancers of tissues that are not directly exposed to the environment, such as cancers of the breast and prostate, and leukemias.
Furthermore, the Cornell team's analysis of the published research found that allergies associated with tissues that are exposed to environmental factors such as eczema, hives, hay fever, and animal and food allergies - were most strongly associated with lower rates of cancers in exposed tissues.
The resarchers believe that the reason for the reduced cancer rates in allergy patients lies in the increased expulsion of foreign material that could be carcinogenic.
"The idea is that the immunoglobulin E system and its associated allergy symptoms serve a common prophylactic function," Sherman said, "namely engulfing in mucous and rapidly expelling pathogens, natural venoms and toxins and other potentially carcinogen-carrying antigens before they can trigger neoplasia [the abnormal proliferation of cells]."
One major allergic disease that doesn't seem to protect against certain types of cancer is asthma which is linked to higher rates of lung cancer. The reason for this is likely because unlike other allergies which increases mucus production and excretion, asthma reduces the ability of the lungs to expel mucus, and with it potentially carcinogenic materials.
So essentially allergies (asthma withstanding) act as a protective preventative mechanism that actively removes cancer-causing chemicals from the body.
Asked if allergy sufferers should routinely suppress all allergy symptoms with medications? Sherman said the jury is still out. He believes however that, allergies are not merely a sign of immune dysfunction, but rather are the evolved front line of defense against certain parasites and cancers. He likens allergic reactions to fevers and morning sickness; uncomfortable responses that survived natural selection because they provided direct benefits.
So what does this mean for us allergy sufferers? The study's findings certainly fly in the face of accepted wisdom about allergies and also give us a lot to think about. As Sherman says "the jury is still out" so further studies into the allergy-cancer connection are needed but if your allergy symptoms are bearable it might be worth holding off on the medication and remedies until you really need them....