Effects of phytosterol-enriched corn-wheat germ blended oil on immune markers and T-cell subsets in Chinese adults with dyslipidemia: a secondary analysis of a randomized controlled trial

Dyslipidemia is associated with chronic low-grade inflammation and immune dysfunction, but the immunological effects of dietary phytosterols in humans remain unclear. We conducted a secondary analysis of an outcome-assessor-blinded, randomized controlled feeding trial to evaluate the effects of a high-phytosterol (HPS) diet, using phytosterol-enriched corn–wheat germ blended oil, compared with a low-phytosterol (LPS) diet using peanut oil, on systemic inflammatory markers, humoral immune markers and peripheral blood lymphocyte subsets in Chinese adults with dyslipidemia. After a 2-week run-in period, 104 participants were randomized to the HPS group (n=52) or the LPS group (n=52) for 12 weeks. In intention-to-treat analyses, the HPS group had a higher CD4 + /CD8 + ratio at 12 weeks than the LPS group (adjusted mean difference: 0.561; 95 % CI: 0.060, 1.063; P = 0.03) and a lower CD8 + T-cell count (adjusted mean difference: -116.315 cells/μL; 95 % CI: -215.781,-16.849; P = 0.02). No significant between-group differences were observed for systemic inflammatory markers, humoral immune markers or most other lymphocyte subset outcomes. In per-protocol analyses, the difference in CD4 + /CD8 + ratio remained significant, whereas the reduction in CD8 + T-cell count was attenuated. These exploratory findings suggest that a 12-week phytosterol-enriched corn–wheat germ blended oil intervention may be associated with changes in T-cell subset balance in adults with dyslipidemia, although the results should be interpreted cautiously given the exploratory nature of this secondary analysis.