Associations of Fish and Fish Oil Consumption With Incident Inflammatory Bowel Disease: A Population-Based Prospective Cohort Study

To the Editors:

We recently read with great interest Fu et al’s¹ work on the associations of fish and fish oil consumption with incident inflammatory bowel disease (IBD). The authors posit a viewpoint that individuals who consume fish oil–rich foods at a higher frequency have a lower incidence of IBD compared with those with lower fish intake. However, several previous studies indicate that the consumption of fish, such as salmon, mackerel, and sardines, does not confer benefits to the condition of individuals with IBD.^2–4 This conclusion, in contrast to certain findings from previous studies, has prompted us to hold a different perspective on this viewpoint.

First, the inconsistency in this conclusion may be attributed to variations in the types of fish and fish oil–rich foods consumed. Research suggests that certain types of fish contain significant amounts of trans fatty acids and saturated fatty acids, both of which exhibit proinflammatory effects within long-chain fatty acids. An epidemiological study indicated that an excessive intake of foods associated with these fatty acids not only fails to reduce the incidence of IBD, but also may exacerbate the severity of the disease in individuals with IBD.⁵ Furthermore, a multicenter study has demonstrated that the consumption of a substantial quantity of foods containing trans fatty acids increases the risk of active recurrence in patients with IBD.⁶ The fish and fish oil–rich foods investigated in this study are abundant in essential nutrients such as omega-3 fatty acids, DHA, iodine, protein, selenium, and others, contributing to a reduced risk of IBD. Following a search of databases including PubMed and EMBASE, Marton et al⁷ concluded that omega-3 fatty acids not only alleviate intestinal inflammation in ulcerative colitis patients, but also inhibit the release of inflammatory factors, reduce disease activity, and improve the quality of life for patients with Crohn’s disease. Second, it is essential to note that this study primarily focused on adults 40 to 69 years of age and did not encompass the age group of 20 to 40 years. Such a study design introduces limitations to the generalizability and applicability of the results to a certain extent. In several previous studies concerning the association between fatty acid intake and the incidence of IBD, participants across the age spectrum of 20 to 40 years were included.^6,8

In conclusion, future research should undertake a more detailed examination of specific components within fish oil–rich foods. Additionally, stratification of the study population by age is essential to accurately assess the impact of these components on the incidence of IBD.

Funding

None received.

Conflicts of Interest

The authors declare that they have no conflicts of interest.

References

Author notes