AIM To determine lipid species that change in response to a change in dairy consumption. In addition, to investigate whether dairy associated lipid species are correlated with changes in measures of vascular structure and function.METHODS A 12-mo randomised controlled trial was conducted to determine the effect of increased consumption of fruit, vegetables and dairy, compared to usual diet, on measures of vascular structure and function in adults with type 1 and type 2 diabetes(n = 108). Thispaper comprises post-hoc analyses investigating the relationship between dairy intake, serum lipid species and vascular health. Central and peripheral blood pressure, carotid femoral pulse wave velocity, augmentation index, serum lipid species and dietary intake were measured at baseline and 3-mo. Common carotid artery intima media thickness was measured at baseline and 12-mo.RESULTS Serum lipid species [lysophosphatidylcholine(LPC) 14:0, LPC 15:0, LPC 16:1, phosphatidylcholine(PC) 29:0 PC 30:0, PC 31:0 and cholesterol ester(CE) 14:0] were associated with the change in full fat dairy consumption(rho 0.19-0.25; P < 0.05). The 3-mo change in some lipids was positively associated with the 3-mo change in central systolic [LPC 14:0(rho 0.30; P = 0.007), PC 30:0(rho 0.28; P = 0.010)] and diastolic blood pressure [LPC 14:0(rho 0.32; P = 0.004), LPC 15:0(rho 0.23; P = 0.04), LPC 16:1(rho 0.23; P = 0.035), PC 29:0(rho 0.28; P = 0.01), PC 30:0(rho 0.36; P = 0.001), PC 31:0(rho 0.30; P = 0.007)] and 12-mo change in common carotid artery intimal medial thickness [CE 14:0(rho 0.22; P = 0.02)]. Pulse wave velocity and augmentation index were unrelated to dairy and lipid species.CONCLUSION An increase in dairy associated lipids appears to be associated with an increase in blood pressure and common carotid intimal medial thickness. AIM To determine lipid species that change in response to a change in dairy consumption. In addition, to investigate whether dairy associated lipid species are associated with changes in measures of vascular structure and function. the effect of increasing consumption of fruit, vegetables and dairy, compared to usual diet, on measures of vascular structure and function in adults with type 1 and type 2 diabetes (n = 108). intake, serum lipid species and vascular health. Central and peripheral blood pressure, carotid femoral pulse wave velocity, augmentation index, serum lipid species and dietary intake were measured at baseline and 3-mo. Common carotid artery intima media thickness was measured at baseline and 12-mo.RESULTS Serum lipid species [lysophosphatidylcholine (LPC) 14: 0, LPC 15: 0, LPC 16: 1, phosphatidylcholine (PC) 29: 0 PC 30: 0, PC 31: 0 and cholesterol ester (CE) 14: 0] were associated with the change in full fat dairy consumption (rho 0.19-0.25; P <0.05). The 3-mo change in some lipids was positively associated with the 3-mo (rho 0.30; P = 0.007), PC 30: 0 (rho 0.28; P = 0.010)] and diastolic blood pressure [LPC 14: 0 (Rho 0.23; P = 0.001), PC 30: 0 (rho 0.36; P = 0.001) and PC 30: 0 , PC 31: 0 (rho 0.30; P = 0.007)] and 12-mo change in common carotid artery intimal medial thickness [CE 14: 0 dairy and lipid species. CONCLUSION An increase in dairy associated lipids appears to be associated with an increase in blood pressure and common carotid intimal medial thickness.