open to eligible females ages 25 years to 40 years
The main objectives of this study are to test the hypotheses that: 1) consumption of beverages sweetened with sucrose will increase risk factors for cardiovascular disease to a greater extent than a naturally-sweetened fruit juice such as orange juice, and 2) chronic psychological stress may augment the adverse metabolic effects of sugar intake. The study intervention consists of 2-week's consumption of 25% of energy as sugar provided either as a sucrose-sweetened beverage or naturally-sweetened orange juice.
open to eligible people ages 21 years and up
A Mediterranean dietary pattern emphasizing an abundance of plant-based foods including nuts, moderate intakes of fish, poultry and low-fat dairy products, and use of extra virgin olive oil as the main source of fat has been associated with reduced risk of cardiovascular disease (CVD), and such a pattern has been advocated by the 2015 U.S. Dietary Guidelines Advisory Committee. The strongest experimental support for this recommendation derives from the success of the recent PREDIMED CVD outcomes trial, and studies indicating that a Mediterranean-style diet improves lipoprotein and oxidative markers of cardiovascular disease risk in comparison to either low-fat or Western dietary patterns. However, in none of these studies were comparisons made between the effects of Mediterranean-style diets with low-/nonfat vs. full-fat dairy foods. The overall objective of the present proposal is to determine whether the inclusion of full-fat rather than low- and nonfat dairy foods in a Mediterranean dietary pattern based on that used in the PREDIMED study results in similar improvements in biomarkers of CVD risk. Specifically, we will test the hypotheses that 1) a standard Mediterranean diet will lower LDL-C and apoB compared to a Western diet; 2) modification of the Mediterranean diet by replacing low-fat dairy products with high-fat dairy (3 servings/day; high-dairy fat Mediterranean diet) will not significantly increase LDL-C and apoB but may raise large buoyant LDL particles compared with a standard Mediterranean diet; and 3) the high dairy fat and standard Mediterranean diets will result in comparable reductions in levels of inflammatory markers and oxidized LDL, and improvements in endothelial function compared to a Western diet.
Sorry, in progress, not accepting new patients
There is growing epidemiological evidence that consumption of red meat is associated with greater incidence of Cardiovascular Disease (CVD) than either white meat or non-meat foods. Research from our group has shown that a high saturated fat (SF) diet with a moderate red meat content selectively increases intermediate density lipoproteins (IDL) and larger low density lipoproteins (LDLs), which are more weakly associated with CVD risk than smaller LDLs. In contrast, the investigators have found that with a similar intake of SF, high beef consumption results in a preferential increase in small and medium LDL particles that are strongly related to CVD. To date, no studies have directly compared the lipoprotein effects of red meat with that of other food sources of protein in the context of both high and low saturated fat intake. The overall objective of this project is to test the hypothesis that the effects of SF on lipoprotein markers of CVD risk are influenced by sources of dietary protein. The investigators hypothesize that adverse effects of SF on plasma levels of LDL-cholesterol (C), apolipoprotein B (apo B), and atherogenic LDL particles are greater in a diet with a high content of red meat than in diets in which the major proteins are from white meat (poultry) or non-meat sources. The investigators propose a clinical trial in which 180 healthy men and women will be randomized to high SF or low SF diet groups, and within each group, consume diets with equivalent amounts of protein from red meat, white meat, and non-meat sources for 4 wks each in random order. Specifically, the investigators will test whether: (1) With high SF, the red meat diet, compared to the other protein sources, will result in higher levels of LDL-C, apoB, small and medium LDL, and total/high density lipoprotein (HDL)C; (2) With low SF, dietary protein source will not be related to any of these measurements; (3) With both the white meat and non-meat protein diets, increased LDL-C with high vs. low SF will be due primarily to increases in large LDL, whereas with red meat the additional increase in small and medium LDL will result in greater increases in plasma apoB and total LDL particle number. Aim 4 will test hypotheses that increases in small and medium LDL with high SF plus red meat are related to increased activity of hepatic lipase, a key determinant of small LDL production, and that increases in large LDL induced by high SF are related to suppression of LDL receptors. The investigators will also assess the effects of protein source and saturated fat content on markers of insulin resistance, inflammation and endothelial function.
Sorry, in progress, not accepting new patients
Much attention has been directed at the unhealthy effects of sugar-sweetened beverages (SSBs), as an increase in their consumption has paralleled the rise obesity rates. In adults, SSBs have been shown to promote ectopic fat storage and raise plasma triglycerides compared to equivalent amounts of semi-skim (1.5%) milk, water, or diet beverages. Replacement of soda with milk had the added benefit of also reducing systolic blood pressure. While several studies have investigated the effects of SSBs on weight gain in children, no published studies have investigated their effects on lipid and lipoprotein risk factors under isocaloric conditions in metabolically at-risk adolescents, who are among the greatest consumers of SSBs. The main objective of this study is to test whether isocaloric replacement of soda with reduced fat milk will significantly improve atherogenic dyslipidemia, blood pressure, insulin sensitivity, and liver function in overweight and obese adolescents who are habitual soda consumers. The investigators will test this in a 8 week randomized two period crossover trial in 30 overweight and obese adolescent males who are self-reported habitual consumers of SSBs. Participants will consume energy equivalent amounts of SSB (24oz soda containing high fructose corn syrup per day), and reduced fat milk (2% milk fat) for 3 weeks each, in random order, separated by a 2-week washout. Anthropometrics, blood pressure, and blood samples will be collected at screen and at the end of each intervention period. Plasma measurements will include LDL peak particle diameter; lipoprotein subclass concentrations; triglycerides; total, LDL, and HDL-cholesterol; apolipoproteins; glucose, insulin, and insulin resistance; high sensitivity C-reactive protein; uric acid; and liver enzymes.