| dc.description.abstract | About half of all deaths in developed countries are caused by cardiovascular disease. It is well known that cardiovascular disease (CVD) risk can be influenced by diet, but optimal dietary content of fatty acids continues to be debated. The effect of fatty acid composition of ground beef on selected cardiovascular disease risk indicators was evaluated with two primary goals. The first goal was to document effects of ground beef fatty acid composition on plasma lipoprotein concentrations, whereas the second goal was to determine the effects of ground beef fatty acid composition on gene expression in peripheral blood mononuclear cells (PBMC). In both studies the results were compared between men and women.
Twelve men and women over age of 45 out of initially 15 completed a two-way crossover design. Subjects consumed five, 114-g ground beef patties per week for 5-wk periods separated by a 3-wk washout period. Patties contained on average 20% fat and monounsaturated fatty acid (MUFA): saturated fatty acid (SFA) of 0.8 and 1.1 for low- MUFA (conventional) ground beef high-MUFA (premium) ground beef patties, respectively. Blood was collected from each subject before and at the end of each diet period. Overall, the ground beef interventions decreased total plasma cholesterol, triacylglycerol, and very low density lipoprotein (VLDL) cholesterol. Plasma concentrations of high density lipoprotein (HDL) cholesterol and low density lipoprotein (LDL) cholesterol decreased and increased, respectively with premium ground beef
consumption. The change in HDL cholesterol was significant in women but not in men suggesting that premium ground beef consumption had a greater impact on women than in men.
For the second goal PBMC were isolated and the expression of selected genes was quantified by real-time PCR. ATP-binding cassette A1, ATP-binding cassette G1, and low-density lipoprotein receptor relative expression was increased with premium ground beef consumption. A significant increase was seen in stearoyl-Coenzyme-A desaturase 1 expression after premium ground beef treatment. With the exception of stearoyl-Coenzyme-A desaturase 1, all these genes were down-regulated with conventional ground beef consumption. Both sterol regulatory element binding transcription factor 1 and mediator complex subunit 1 were down-regulated after each beef patty treatment, but the effect was significant after consuming conventional ground beef. This suggests that genes involved in cholesterol metabolism were down-regulated with conventional ground beef consumption; whereas genes related to lipogenesis were up-regulated with premium ground beef consumption. From these data we concluded that different ground beef dietary interventions have different impacts on the PBMC gene expression that is related to cholesterol metabolism, inflammation and liver X receptor pathways. | en |
