Controlled Clinical Study to Determine Novel Health Benefits of Cheese Consumption

Summary of Proposed Research:

This project will involve four controlled 4 wk feeding periods in individuals with metabolic syndrome (currently 1/3 of US adults). After a 2 wk run-in period, 20 subjects will be fed one of three diets in a randomized and balanced order: a typical American High-Carb diet high in cheese (6 oz/day), a High-Carb diet low in cheese (0 oz/day), or a Moderate-Carb, high-cheese diet (6 oz/day), Low-Carb, high cheese where cheese displaces an isocaloric amount of carbohydrate. There will be a 2 wk washout period separating trials during which subjects consume their normal diet. Specific menus will be designed for each feeding phase and all food will be prepared for subjects. Testing will occur at baseline and after each feeding period. Measures of cholesterol beyond standard LDL- and HDL-cholesterol will be done by examining lipoprotein particle size, apolipoproteins, and fatty acid composition [i.e., accumulation of saturated fat in blood and tissues, palmitoleic acid (highly linked to cardiovascular disease), and detection of phytanic acid (a uniquely bioactive fatty acid in dairy fat)]. Changes in whole body and regional fat, including measures of visceral fat and liver fat, will be examined non-invasively by dual-energy X-ray absorptiometry (DXA) and magnetic resonance imaging (MRI).

Inclusion criteria

• Waist circumference (≥101.6 cm men, ≥88.9 cm women)
• Blood pressure (≥130/85 mm Hg) or current use of antihypertensive medication
• Fasting plasma glucose (≥100 mg/dL)
• Triglycerides (≥150 mg/dL)
• HDL-C (<40 mg/dL men, <50 mg/dL women)

Exclusion criteria

• Hypercholesterolemia
• Diabetes
• Liver, kidney or other metabolic or endocrine dysfunction, gastrointestinal disorders
• Regular smokers
• Lactose-intolerant
• Consume excessive amounts of alcohol (>3 drinks/d)
• Have used cholesterol, diabetic, antibiotic or antifungal medications in the past 3 months
• Women who are pregnant or lactating
• Participants taking any probiotics or supplements known to affect serum lipid levels, inflammation, antioxidant status or the gut microbiota will be asked to discontinue use to allow for washout of any metabolic effects.