BACKGROUND: Butter is known to have a cholesterol-raising effect and, therefore, has often been included as a negative control in dietary studies, whereas the effect of moderate butter intake has not been elucidated to our knowledge.

OBJECTIVE: We compared the effects of moderate butter intake, moderate olive oil intake, and a habitual diet on blood lipids, high-sensitivity C-reactive protein (hsCRP), glucose, and insulin.

DESIGN: The study was a controlled, double-blinded, randomized 2 × 5-wk crossover dietary intervention study with a 14-d run-in period during which subjects consumed their habitual diets. The study included 47 healthy men and women (mean ± SD total cholesterol: 5.22 ± 0.90 mmol/L) who substituted a part of their habitual diets with 4.5% of energy from butter or refined olive oil.

RESULTS: Study subjects were 70% women with a mean age and body mass index (in kg/m(2)) of 40.4 y and 23.5, respectively. Butter intake increased total cholesterol and LDL cholesterol more than did olive oil intake (P < 0.05) and the run-in period (P < 0.005 and P < 0.05, respectively) and increased HDL cholesterol compared with the run-in period (P < 0.05). No difference in effects was observed for triacylglycerol, hsCRP, insulin, and glucose concentrations. The intake of saturated fatty acids was significantly higher in the butter period than in the olive oil and run-in periods (P < 0.0001).

CONCLUSIONS: Moderate intake of butter resulted in increases in total cholesterol and LDL cholesterol compared with the effects of olive oil intake and a habitual diet (run-in period). Furthermore, moderate butter intake was also followed by an increase in HDL cholesterol compared with the habitual diet. We conclude that hypercholesterolemic people should keep their consumption of butter to a minimum, whereas moderate butter intake may be considered part of the diet in the normocholesterolemic population. This trial was registered at clinicaltrials.gov as NCT02116829.