Food allergy, intolerances and risk of bowel cancer
Food allergies usually cause overt symptoms within a few minutes or up to an hour after eating the suspect food.
They can cause many symptoms such as, a drop in blood pressure, itching skin (hives) or mouth, vomiting, diarrhoea or stomach pain or in severe cases anaphylaxis.
Anaphylaxis is potentially life threatening and affects breathing, although deaths are rare in Australia this is due to timely medical intervention.
The common allergens are wheat (Coeliac Disease), eggs, cow's milk, peanuts and tree nuts; others may by fish, seafood, sesame and soy.
Sometimes allergies can be outgrown (except wheat and gluten allergies). It is always important to be tested by your GP to confirm diagnosis of food allergens.
Coeliac Disease is a true allergy which is not outgrown, where a complete abstinence of wheat and gluten is necessary. Caution is recommended to read labels as many pre-packaged foods contain wheat or gluten.[3 & 4]
Food intolerances usually cause symptoms within 30 minutes and up to two hours, mostly presenting with gastric symptoms such as gas, bloating, cramps, nausea and diarrhoea.
Intolerances can be to fruit sugars, lactose from milk, grain sugars, including wheat and corn, artificial sugars and sugars in beans and other foods.
These are also known as Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols (FODMAPS).
Food intolerances can also be reactive to naturally occurring and added chemicals in foods. Your GP can test for FODMAP intolerances with a simple breath test. A dietician or nutritionist can assist with other intolerances. Once diagnosed caution is recommended to read labels, as most pre-packaged foods contain sugars, corn syrup, gluten as well as added chemicals.
Food intolerances, allergy and Irritable Bowel Syndrome (IBS), and risk of bowel cancer
Food intolerances and allergy are often associated with IBS. Although IBS is not linked to the development of bowel cancer it is best to consult your GP if you have changes in bowel function or persistent IBS symptoms. Very rarely it can mask the symptoms of bowel cancer. [3 & 5]
Coeliac disease and risk of bowel cancer
Limited studies have identified that coeliac patients who adhered to a gluten free diet did not have an increased risk of bowel cancer, however those who did not adhere to a strict gluten free diet were associated with an increased risk. At this point in research there is little evidence of risk, further studies are needed. 
- Gastroenterology Specialties and Lincoln Endoscopy Center. (2015). Food allergies and intolerances, Retrieved from http://www.gidocs.net/patient-education/diet-and-medications/food-allergies-and-intolerances/
- Australian Society of Clinical Immunology and Allergy. (2014). Food Allergy. Retrieved from http://www.allergy.org.au/patients/food-allergy/food-allergy
- Bernhard- Madsen C et al. (2014). Risk Management of food allergy. Elsevier Press. Kidlington, Oxford UK & Waltham USA.
- Hattersley S., Ward R., Baka A., & Crevel RWR. (2014). Advances in the risk management of unintended presence of allergenic foods in manufactured food products – An overview. Food and Chemical Toxicology, 67, 255-261.
- Hsiao CW et al. (2014). Association between irritable bowel syndrome and colorectal cancer: A nationwide population-base study. Euro J Int Med, 25 (1), 82-86. DOI: http://dx.doi.org/10.1016/j.ejim.2013.11.005
- Pereyra et al. (2013). Risk of colorectal neoplasia in patients with celiac disease: A multicentre study. J Crohns, 4(12), e672-e677. Retrieved from http://www.sciencedirect.com/science/article/pii/S1873994613002092 doi:10.1016/j.crohns.2013.06.005