Blood Lipid Responses to Diets Enriched with Cottonseed Oil Compared With Olive Oil in Adults with High Cholesterol in a Randomized Trial

BACKGROUND: Increasing unsaturated fat intake is beneficial for cardiovascular health, but the type of unsaturated fat to recommend remains equivocal. OBJECTIVES: We investigated the effects of an 8-week diet intervention that was rich in either cottonseed oil (CSO; PUFA rich) or olive oil (OO; MUFA rich) on blood lipids in hypercholesterolemic adults. METHODS: Forty-three men and women with hypercholesterolemia (53 ± 10 years; BMI, 27.6 ± 4.8 kg/m(2)) completed this randomized parallel clinical trial consisting of an 8-week partial outpatient feeding intervention. Participants were given meals and snacks accounting for ∼60% of their daily energy needs, with 30% of energy needs from either CSO (n = 21) or OO (n = 22). At pre- and postdiet intervention visits, participants consumed a high-SFA meal (35% of total energy needs; 70% of energy from fat). The primary outcomes of fasting cholesterol profiles and secondary outcomes of postprandial blood lipids and glycemic markers were assessed over a 5-hour period. RESULTS: There were greater reductions from baseline to week 8 in fasting serum total cholesterol (TC; −17.0 ± 3.94 mg/dL compared with −2.18 ± 3.72 mg/dL, respectively; P = 0.008), LDL cholesterol (−19.7 ± 3.94 mg/dL compared with −5.72 ± 4.23 mg/dL, respectively; P = 0.018), non–HDL cholesterol (−20.8 mg/dL ± 4.00 compared with −6.61 ± 4.01 mg/dL, respectively; P = 0.014), and apoB (−11.8 mg/dL ± 2.37 compared with −3.10 ± 2.99 mg/dL, respectively; P = 0.05), in CSO compared with OO. There were also visit effects from baseline to week 8 for increases in HDL cholesterol (CSO, 56.5 ± 2.79 mg/dL to 60.2 ± 3.35 mg/dL, respectively; OO: 59.7 ± 2.63 mg/dL to 64.1 ± 2.24 mg/dL, respectively; P < 0.001), and decreases in the TC:HDL-cholesterol ratio (CSO, 4.30 ± 0.27 mg/dL to 3.78 ± 0.27 mg/dL, respectively; OO, 3.94 ± 0.16 mg/dL to 3.57 ± 0.11 mg/dL, respectively; P < 0.001), regardless of group assignment. In response to the high-SFA meal, there were differences in postprandial plasma glucose (P = 0.003) and triglyceride (P = 0.004) responses and a trend in nonesterified fatty acids (P = 0.11) between groups, showing protection in the postprandial state from an occasional high-SFA fat meal with CSO, but not OO, diet enrichment. CONCLUSIONS: CSO, but not OO, diet enrichment caused substantial improvements in fasting and postprandial blood lipids and postprandial glycemia in hypercholesterolemic adults. This trial was registered at clinicaltrials.gov as NCT04397055.