Impact of low-fat and full-fat dairy foods on fasting lipid profile and blood pressure: exploratory endpoints of a randomized controlled trial.
Study Goal
The researchers aimed to compare the effects of limited-dairy, low-fat dairy, and full-fat dairy diets on cardiovascular disease (CVD) risk factors in individuals with metabolic syndrome.
Results Summary
The study found no significant differences in fasting lipid profiles or diastolic blood pressure between the diets, though there was a modest decrease in systolic blood pressure with the low-fat dairy diet. Full-fat dairy did not adversely impact CVD risk factors compared to low-fat or limited-dairy diets.
Population
72 participants with metabolic syndrome (66 completed per-protocol analysis).
Effective Dosage
3.3 servings/day of low-fat or full-fat milk, yogurt, and cheese.
Duration
12 weeks.
Interactions
None mentioned.
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
limited-dairy diet | no change | fasting serum total, LDL, and HDL cholesterol; triglycerides; free fatty acids; or cholesterol content in 38 isolated plasma lipoprotein fractions | participants with metabolic syndrome | P > 0.1 for all variables | no intervention effect | #1 |
low-fat dairy diet | no change | fasting serum total, LDL, and HDL cholesterol; triglycerides; free fatty acids; or cholesterol content in 38 isolated plasma lipoprotein fractions | participants with metabolic syndrome | P > 0.1 for all variables | no intervention effect | #2 |
full-fat dairy diet | no change | fasting serum total, LDL, and HDL cholesterol; triglycerides; free fatty acids; or cholesterol content in 38 isolated plasma lipoprotein fractions | participants with metabolic syndrome | P > 0.1 for all variables | no intervention effect | #3 |
limited-dairy diet | no change | diastolic blood pressure | participants with metabolic syndrome | - | no intervention effect | #4 |
low-fat dairy diet | no change | diastolic blood pressure | participants with metabolic syndrome | - | no intervention effect | #5 |
full-fat dairy diet | no change | diastolic blood pressure | participants with metabolic syndrome | - | no intervention effect | #6 |
low-fat dairy diet | decrease | systolic blood pressure | participants with metabolic syndrome | -1.6 ± 8.6 mm Hg | significant intervention effect | #7 |
limited-dairy diet | increase | systolic blood pressure | participants with metabolic syndrome | +2.5 ± 8.2 mm Hg | trend for an increase | #8 |
full-fat dairy diet | no change | fasting lipid profile or blood pressure | men and women with metabolic syndrome | - | no effects | #9 |
BACKGROUND: Dietary guidelines traditionally recommend low-fat dairy because dairy's high saturated fat content is thought to promote cardiovascular disease (CVD). However, emerging evidence indicates that dairy fat may not negatively impact CVD risk factors when consumed in foods with a complex matrix. OBJECTIVE: The aim was to compare the effects of diets limited in dairy or rich in either low-fat or full-fat dairy on CVD risk factors. METHODS: In this randomized controlled trial, 72 participants with metabolic syndrome completed a 4-wk run-in period, limiting their dairy intake to ≤3 servings/wk of nonfat milk. Participants were then randomly assigned to 1 of 3 diets, either continuing the limited-dairy diet or switching to a diet containing 3.3 servings/d of either low-fat or full-fat milk, yogurt, and cheese for 12 wk. Exploratory outcome measures included changes in the fasting lipid profile and blood pressure. RESULTS: In the per-protocol analysis (n = 66), there was no intervention effect on fasting serum total, LDL, and HDL cholesterol; triglycerides; free fatty acids; or cholesterol content in 38 isolated plasma lipoprotein fractions (P > 0.1 for all variables in repeated-measures ANOVA). There was also no intervention effect on diastolic blood pressure, but a significant intervention effect for systolic blood pressure (P = 0.048), with a trend for a decrease in the low-fat dairy diet (-1.6 ± 8.6 mm Hg) compared with the limited-dairy diet (+2.5 ± 8.2 mm Hg) in post hoc testing. Intent-to-treat results were consistent for all endpoints, with the exception that systolic blood pressure became nonsignificant (P = 0.08). CONCLUSIONS: In men and women with metabolic syndrome, a diet rich in full-fat dairy had no effects on fasting lipid profile or blood pressure compared with diets limited in dairy or rich in low-fat dairy. Therefore, dairy fat, when consumed as part of complex whole foods, does not adversely impact these classic CVD risk factors. This trial was registered at clinicaltrials.gov as NCT02663544.