· Investigate the influence of omega-3 fatty acid feeding on lipoprotein lipid composition and peripheral tissue lipid metabolism.
Dietary intake of omega-3 fatty acids in numerous studies has been associated with improvement in the risk of developing vascular disease. In healthy men, we found that consuming long chain omega-3 fatty acids alters lipoprotein particle composition of these compounds in a manner suggesting replacement of omega-6 fatty acids in phospholipids, as well as triglyceride pools. In addition, we have shown that these changes extend to parallel changes in the oxygenated metabolites of these compounds, and that these bioactive metabolites are accessible by physiologically relevant enzymatic systems. Together, these results suggest the potential for lipoprotein particles to act as vehicles for the lipase-dependent delivery of bioactive lipids to peripheral cell types with broad impacts on physiology.
· Examine the effect of a high trans-fatty acids intake on abdominal obesity and risk markers of type 2 diabetes and cardiovascular disease in lean and overweight women.
Long term trans-fatty acid consumption has been linked to adverse health risks including untoward alterations in plasma lipid profiles and accumulation of hepatic lipids. In a controlled 16wk human feeding study, individuals showed uniform enrichment in erythrocyte trans-fatty acids by 8wks and a dyslipidemia associated with increased cardiovascular health risks was observed. Evidence for hepatic fat accumulation or changes in body mass was not seen in this study.
· Identify metabolic and gene expression markers of cardiovascular disease.
Atherosclerotic plaques are known to show evidence of oxidative changes to lipids, however it remains unclear to what extent enzymes are induced that increase these levels. In one aspect of this project, strong evidence was found at the gene transcription, protein expression, and metabolic profile levels to support the activation of the 15-lipoxygenase-1 gene (15LOX1) in human atherosclerotic plaques. This finding enhances our understanding of the inflammatory processes occurring within atherosclerotic plaques.
· Investigate responses to fixed dietary challenges as a tool to: 1) investigate interactions in complex metabolic networks and 2) classify individuals into groups which may benefit from distinct dietary intakes.
· Explore relationships of plasma free fatty acids with obesity, fat distribution, blood pressure, and steroid hormones in male and female Caucasian and African American adults.
· Evaluate the direct impact of dietary ratios of monounsaturated and saturated fat on high density lipoprotein structure and function in healthy adult men, using ground beef from cattle raised on feed with varying lipid sources to manipulate the dietary intake of fatty acids.