I have just read the summary of a paper published in the Lancet last year and I think it bares consideration on these pages.
I only have access to the summary as the paper is over 30 bucks but it highlights both the difficulty separating the diagnosis of IBS from more 'profound' disease, and, in my mind at least, highlights the need to have these major illnesses considered and then dismissed, in the first instance!
I like many floundered around while I was trying to diagnose my condition and looking back there were few who mentioned or even tested for 'red line' disease like bowel cancer or IBD.
Nutritionists and alternate medicine practitioners are a mix bag of advisers. Make sure you have dispelled the possibility of major disease before embarking on their program of diet and supplementation!
Here is the Lancet summary text - Link: thelancet.com/journals/lang...
Irritable bowel syndrome (IBS) is a common functional bowel disorder characterised by symptoms of recurrent abdominal pain associated with a change in bowel habit. This condition is one of the most frequent reasons to seek a gastroenterology consultation in primary and secondary care. The diagnosis of IBS is made by identifying characteristic symptoms, as defined by the Rome criteria, and excluding organic gastrointestinal diseases that might otherwise explain these symptoms. Organic conditions that can be mistaken for IBS include coeliac disease, inflammatory bowel disease (IBD), colorectal cancer, and, in those with diarrhoea-predominant symptoms, chronic gastrointestinal infections, microscopic colitis, and primary bile acid diarrhoea. The concept of small intestinal bacterial overgrowth being associated with IBS is shrouded with controversy and uncertainty, mainly because of invalid tests due to poor sensitivity and specificity, potentially leading to incorrect assumptions. There is insufficient evidence to link IBS-type symptoms with exocrine pancreatic insufficiency or with symptomatic uncomplicated diverticular disease, since both are hampered by conflicting data. Finally, there is growing appreciation that IBS can present in patients with known but stable organic gastrointestinal diseases, such as quiescent IBD or coeliac disease. Recognising functional gut symptoms in these individuals is paramount so that potentially harmful escalations in immunosuppressive therapy can be avoided and attention can be focused on addressing disorders of gut–brain interaction. This Review endeavours to aid clinicians who practise adult gastroenterology in recognising the potential overlap between IBS and organic gastrointestinal diseases and highlights areas in need of further research and clarity.
IBS and Coeliac 
Functional IBS and uncontrollable diarrhoea - what can help?
IBS flare ups/IBD tests/HELP! 😞
IBS and menstrual cycle
