A Randomized Trial of omega-3 Fatty Acid Supplementation and Circulating Lipoprotein Subclasses in Healthy Older Adults

Background Omega-3 (n-3) PUFAs are recognized for triglyceride-lowering effects in people with dyslipidemia, but it remains unclear if n-3-PUFA intake influences lipoprotein profiles in older adults without hypertriglyceridemia. Objectives The objective was to determine the effect of n-3-PUFA supplementation on plasma lipoprotein subfractions in healthy older men and women in the absence of cardiovascular disease (CVD) or hypertriglyceridemia. This was a secondary analysis and considered exploratory. Methods Thirty young (20-35 y old) and 54 older (65-85 y old) men and women were enrolled in the study. Fasting plasma samples were collected. After baseline sample collection, 44 older adults were randomly assigned to receive either n-3-PUFA ethyl esters (3.9 g/d) or placebo (corn oil) for 6 mo. Pre- and postintervention plasma samples were used for quantitative lipoprotein subclass analysis using high-resolution proton NMR spectroscopy. Results The number of large, least-dense LDL particles decreased 17%-18% with n-3 PUFAs compared with placebo (P < 0.01). The number of small, dense LDL particles increased 26%-44% with n-3 PUFAs compared with placebo (similar to 11% decrease; P < 0.01). The cholesterol content of large HDL particles increased by 32% with n-3 PUFAs and by 2% in placebo (P < 0.01). The cholesterol content of small HDL particles decreased by 23% with n-3 PUFAs and by 2% in placebo (P < 0.01). Conclusions Despite increasing abundance of small, dense LDL particles that are associated with CVD risk, n-3 PUFAs reduced total triglycerides, maintained HDL, reduced systolic blood pressure, and shifted the HDL particle distribution toward a favorable cardioprotective profile in healthy older adults without dyslipidemia. This study suggests potential benefits of n-3-PUFA supplementation to lipoprotein profiles in healthy older adults without dyslipidemia, which should be considered when weighing the potential health benefits against the cost and ecological impact of widespread use of n-3-PUFA supplements. This trial was registered at clinicaltrials.gov as NCT03350906.

Automated summary

The study aimed to determine the effect of n-3-PUFA supplementation on plasma lipoprotein subfractions in healthy older adults without cardiovascular disease (CVD) or hypertriglyceridemia. The results showed that n-3-PUFAs reduced the number of large, least-dense LDL particles and increased the number of small, dense LDL particles. They also increased the cholesterol content of large HDL particles and decreased the cholesterol content of small HDL particles. Despite the increase in small, dense LDL particles associated with CVD risk, n-3-PUFAs had beneficial effects on triglyceride levels, HDL levels, blood pressure, and the distribution of HDL particles in healthy older adults without dyslipidemia.