A randomized crossover trial of 30 cardiometabolic-risk adults found that cereals enriched with polyphenols, fibers, omega-3s, and slow-digesting starch significantly reduced intestinal inflammation markers (fecal calprotectin) and metabolic endotoxemia (circulating LPS) compared to control cereals. The intervention specifically increased beneficial bacteria including Bifidobacterium ovatus, B. uniformis, and butyrate-producing Anaerostipes butyriciproducens while lowering harmful branched-chain amino acids. This combination approach represents a sophisticated evolution beyond single-nutrient interventions that have shown mixed results in microbiome research. The simultaneous targeting of multiple inflammatory pathways through coordinated bioactive compounds appears more effective than isolated polyphenol or fiber supplementation alone. For adults with metabolic dysfunction, this suggests that strategically designed functional foods could address the gut-inflammation axis underlying diabetes and cardiovascular disease progression. However, the relatively small sample size and short duration limit broader applicability. The crossover design strengthens causal inference, but longer-term studies are needed to determine whether these microbiome shifts translate into measurable cardiometabolic improvements and whether the benefits persist after discontinuation.