Reversing Glucose and Lipid-mediated Vascular Dysfunction

Inclusion Criteria:

* Lean: BMI \< 25 kg/m
* Normal insulin sensitivity: (calculation based on fasting glucose and insulin concentrations in blood)
* Middle-aged: 18-79 years
* Blood pressure: \< 140 (systolic) and \< 90 mmHg (diastolic
* Weight stable (+/- 5 lbs) for the previous 3 months
* Participants must be willing and able to discontinue taking any vitamin C or E supplements or omega-3 fatty acids beginning 2 weeks prior.
* Able and willing to provide written informed consent

Exclusion Criteria:

* Diabetes mellitus Type I or Type II: fasting glucose \< 126 mg/dL and/or HbA1c \< 6.5%
* Current smoker or History of smoking in the past 3 months.
* Hyperlipidemia: Fasting triglycerides \< 250 mg/dL
* Hypertension: \>130/80 mmHg
* History of heart disease (e.g., myocardial infarction, stent, heart attack, stroke, heart failure, valvular heart disease, cardiomyopathy)
* History of vascular disease (e.g., bypass, stroke)