The effects of consumption of interesterified fats rich in palmitic acid compared with stearic acid on intermediary markers of cardiometabolic disease risk: a randomized controlled trial in healthy adults.

BACKGROUND

Interesterified (IE) fats rich in palmitic acid (16:0) and stearic acid (18:0) are widely used hard fats. Comparative effects of commercially relevant palmitic or stearic acid-rich IE fat blends on cardiometabolic disease (CMD) risk markers remain unclear. It was hypothesized that functionally matched palmitic and stearic acid-rich fats would have equivalent effects on plasma total:high-density lipoprotein (HDL) cholesterol ratio within a predefined equivalence margin of ±0.09.

OBJECTIVES

This study aimed to compare the effects of diets enriched in palmitic or stearic acid, delivered as commercially relevant IE fats and incorporated at realistic levels of dietary intake, on plasma lipid concentrations and other CMD risk markers in healthy participants.

METHODS

In a randomized, crossover trial at 2 centers, 51 healthy participants (aged 35-65 y) consumed diets with either palmitic acid-rich or stearic acid-rich IE fats (10% energy intake) for 6 wk per arm, with a 4-wk washout. IE fats were incorporated into muffins and margarine spreads. The primary outcome was total:HDL cholesterol ratio; secondary outcomes included HDL and low-density lipoprotein cholesterol and fasting and postprandial triacylglycerol, lipoproteins, apolipoproteins, insulin sensitivity, vascular endothelial function, inflammation markers, and fasting liver fat (via proton magnetic resonance spectroscopy, subgroup). Linear mixed models were used to assess intervention effects.

RESULTS

Forty-seven participants (51% female, mean age 52 ± 8 y; body mass index 25.2 ± 2.8 kg/m2) completed the study. No significant differences were observed in total:HDL cholesterol ratio between interventions (stearic compared with palmitic mean difference: 0.05; 95% confidence interval [CI]: -0.08, 0.18). Interleukin-10 concentration decreased after consuming palmitic relative to stearic acid-rich IE fats (-0.14 ng/L; 95% CI: -0.23, -0.06 ng/L). No effects were observed on other outcomes.

CONCLUSIONS

Commercially relevant palmitic acid-rich IE fats consumed at 10% energy for a 6-wk period do not adversely affect total:HDL cholesterol ratio or other CMD risk markers compared with stearic acid-rich fats. Long-term effects could not be determined from this trial. This trial was registered at clinicaltrials.gov as NCT04418102.