The purpose of our study is to understand the extent to which the blood vessels are affected by glucose and fat (lipids) in lean healthy adults and if these changes in the blood vessels contribute to the development of high blood pressure.

Hypertension, obesity, and insulin resistance are associated with elevated muscle sympathetic nerve activity (MSNA), which is important for blood pressure regulation. The measurement of MSNA is safely performed in humans using the microneurographic technique that involves recording sympathetic nerve activity projecting to skeletal muscle using a small microelectrode at the peroneal nerve near the knee.

The health of your blood vessels will be tested in this study, in addition to the activity of the nerves that control the blood vessels. The function of the nerves and blood vessels can be diminished by high blood glucose and lipids, and we will test the ability of a well-known antioxidant, ascorbic acid (vitamin C), to restore the function of the nerves and blood vessels.

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)

Randomized, double-blinded, parallel-design approach study.