Polyunsaturated fatty acids (PUFAs), particularly omega-3 and omega-6 fatty acids, have been investigated for their roles in supporting the health of the small intestine and overall gut function. Scientific evidence suggests that PUFAs can modulate inflammation, influence gut barrier integrity, and affect the composition of gut microbiota. For example, omega-3 PUFAs such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have anti-inflammatory properties and may help reduce inflammation in conditions like inflammatory bowel disease (IBD), which affects the small intestine as well as the colon.

Research in animal models and some human studies indicates that supplementation with omega-3 PUFAs can decrease intestinal permeability ("leaky gut") and reduce the production of pro-inflammatory cytokines. Additionally, PUFAs may help maintain the mucosal layer of the small intestine, thus supporting its function as a barrier and in nutrient absorption. However, while there is a moderate amount of scientific evidence to support these benefits, especially in the context of inflammatory or compromised gut conditions, large-scale, long-term clinical trials in humans are still limited.

In summary, the use of polyunsaturated fatty acids to support small intestine health is grounded in scientific findings, particularly regarding their anti-inflammatory effects and support of gut barrier function, but the strength of evidence is moderate and more research is needed for definitive recommendations.