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Approved Research

Omega-3 polyunsaturated fatty acid intake and colorectal cancer outcomes

Principal Investigator: Professor Mark Hull
Approved Research ID: 73904
Approval date: August 31st 2021

Lay summary

Aims: Bowel cancer is the second most common cause of cancer death in the UK. Approximately 50% of bowel cancer could be prevented through lifestyle modifications. We will test whether high dietary intake (fish intake and fish oil supplement use) reflects body levels of omega-3 fatty acids (O3FA) and if they are associated with a lower risk of bowel cancer in UK Biobank (UKBB) participants.

Scientific Rationale: O3FAs are present naturally in oily-fish and prevent bowel cancer in the laboratory. However, evidence that dietary O3FAs reduce bowel cancer risk in people is inconclusive. This is perhaps due to poor recording of the diet and fish oil supplement use. Some studies have tried to confirm dietary O3FA intake by measuring body levels of O3FA but only included a small proportion of participants, making it difficult to draw definite conclusions. More recent results from population-based studies suggests that O3FAs may reduce bowel cancer in certain parts of the bowel (right-side), but were limited by the number of cases and ability to measure O3FA intake accurately. With the forthcoming cancer registry update and O3FA measurements (in 120,000 participants), this study will help answer these important questions.

Project duration: The project will take place over 12 months. We will examine all UKBB participants' O3FA intake through food frequency (fish intake) and medication (fish oil supplement use) questionnaires. We will identify participants who have been diagnosed and/or died with/from bowel cancer. We will specifically look at bowel cancer in different parts of the bowel, which might be affected differently. Using UKBB data that measured body O3FA levels when participants joined the UKBB study, we will investigate whether O3FA intake is linked to body O3FA levels and how this relates to bowel cancer risk, deaths in different sites of bowel cancer.

Public Health Impact: By evaluating O3FA intake (diet and supplement use) and bowel cancer risk, this study has the potential to influence dietary recommendations and O3FA supplement use preventing bowel cancer and improving outcomes following bowel cancer diagnosis. If the project is able to demonstrate a reduced risk of bowel cancer in specific parts of the bowel, it will contribute knowledge enabling a personalised approach to bowel cancer risk reduction and treatment in the future. The findings could also help inform the dose of O3FA interventions in future clinical trials of O3FA treatment of multiple conditions cancer, heart disease and dementia.