The purpose of the study is to determine whether increasing the dietary intake of n-3 fatty acids by the consumption of oil-rich fish reduces the risk of developing colorectal cancer.

Epidemiological evidence from several countries supports a protective effect of fish consumption on cancer risk and gastrointestinal cancers in particular. Further evidence to support the idea that fish consumption is protective in relation to cancers of the GI tract is now emerging from the European Investigation into Cancer and Nutrition (EPIC).

The FISHGASTRO project is headed by the Institute of Food Research and includes groups from the University of East Anglia, the University of Wageningen, Netherlands and the University of Jena, Germany. The project focuses on assessing the impact of fish consumption on a range of markers of gastrointestinal health associated with ulcerative colitis or colon cancer and on looking at bio-accessibility of a range of nutrients from fish. We aim to recruit a total of 270 patients with gastrointestinal problems in the UK and Netherlands and take biopsy and blood samples before and after asking them to eat two extra portions of fish per week. One group will receive oil rich fish such as salmon while another will be asked to eat white fish. Changes in cell proliferation, apoptosis, inflammatory markers, gene expression and plasma levels of n-3 fatty acids will be compared to a control group only given standard nutritional advice.

Inclusion Criteria:

Ulcerative Colitis Patient Group (Group 1):

• Aged 18 - 80
• Male or female
• Diagnosed with ulcerative colitis
• Attending gastroenterology clinic for routine colonoscopy check-up
• Willing to increase dietary intake of fish for six months
• Willing to undergo a flexible sigmoidoscopy examination

Polyps/Resection Group (Group 2):

• Aged 18 - 80
• Male or female
• A history of polyps in the colon
• Attending gastroenterology clinic for routine colonoscopy check-up
• Willing to increase dietary intake of fish for six months
• Willing to undergo a flexible sigmoidoscopy examination

Control Group (Group 3):

• Aged 18 - 80
• Male or female
• Booked for a colonoscopy examination for the investigation of iron deficiency anaemia of unknown cause (no evidence of macroscopic disease found during examination)
• Willing to increase dietary intake of fish for six months
• Willing to undergo a flexible sigmoidoscopy examination

Exclusion Criteria:

Ulcerative Colitis Patient Group (Group 1) and Polyps/Resection Group (Group 2):

• Allergic to fish
• Receiving anticoagulant therapy
• Diabetics
• Pregnant or breast-feeding
• Organ transplant recipients receiving immunosuppression therapy
• Prosthetic heart valve
• Allergic to pethidine
• Previous diagnosis of bacterial endocarditis

Control Group (Group 3):

Same as Groups 1 and 2 plus:

• Received a diagnosis of colorectal cancer following initial investigative colonoscopy (volunteer will be withdrawn from the study when diagnosed as requiring treatment)
• Received a diagnosis of coeliac disease following initial investigative colonoscopy (volunteer will be withdrawn from the study when diagnosed as requiring a modified diet)