by Jenna Koroly, MS, RD, CSOWM, CDN
The polyunsaturated fatty acids (PUFAs) include two main different types: omega-3 and omega-6, named for the location of the first double bond in the molecule. The omega-3 PUFAs, found in high amounts in certain fish, are anti-inflammatory and may play a role in tumor suppression.
Study
Dietary polyunsaturated fat intake in relation to head and neck, esophageal, and gastric cancer incidence in the NIH-AARP Diet and Health Study
Journal: American Journal of Epidemiology
This prospective cohort study, with median follow-up of 15.5 years, involved over 400,000 participants from six states and two cities in the United States. Food frequency questionnaires from the National Cancer Institute were administered. The authors looked at omega-3 and omega-6 fatty acid subtypes, PUFA intake ratio, and fish high in omega-3 versus omega-6 fatty acids compared with incidence of upper gastrointestinal cancers.
Findings
The authors found:
1. Fish/shellfish intake, mostly due to fish high in omega-3 fatty acids and non-fried fish, was associated with a 20-27% lower risk of head and neck cancers and esophageal adenocarcinoma
2. Long-chain omega-3 PUFA intake, of which the primary source is non-fried fish and shellfish, was associated with a 19-21% lower risk of head and neck cancers and esophageal adenocarcinoma
3. Higher intake of long-chain omega-3 compared to long-chain omega-6 PUFAs was associated with a decreased risk of head and neck cancers and esophageal adenocarcinoma
4. Fish and PUFA intake showed little to no association with esophageal squamous cell carcinoma and gastric cancers [i]
For the Patient and Caregiver
Emphasize intake of foods rich in omega-3 PUFAs, including non-fried fish and shellfish. Omega-3 PUFA rich fish include salmon, tuna, and sardines. Other foods to include that are rich in omega-3 PUFAs are flaxseeds, chia seeds, and walnuts. To see a breakdown of types of PUFAs in foods, check out Table 2 in this fact sheet from the NIH.
For the Healthcare Team
Encourage intake of foods rich in omega-3 PUFAs, particularly to those who may be at risk of upper gastrointestinal cancers. Long-chain omega-3 PUFAs act as “precursors for anti-inflammatory lipid mediators, which can inhibit angiogenesis and induce apoptosis” [Gu et al., 2015 & Azrad et al., 2013 as cited in the current study]. On the other hand, a long-chain omega-6 PUFA called arachidonic acid is a “precursor of pro-inflammatory lipid mediators” [Gu et al., 2015 & Azrad et al., 2013 as cited in the current study].
Reference:
[i] Zamani SA, McClain KM, Graubard BI, Liao LM, Abnet CC, Cook MB, Petrick JL (2020). Dietary polyunsaturated fat intake in relation to head and neck, esophageal, and gastric cancer incidence in the NIH-AARP Diet and Health Study. American Journal of Epidemiology, kwaa024. https://doi.org/10.1093/aje/kwaa024