Overview
The purpose of this pilot research project is to examine the impact of a low-glycemic index (GI) diet on postprandial hypotension and glucose control in individuals with chronic spinal cord injury. The objectives are: 1) To evaluate the effect of the low-GI diet on the magnitude of postprandial systolic blood pressure drop compared to a high-GI control diet. 2)To evaluate the effect of a low-GI diet on postprandial glucose and insulin responses compared to a high-GI control diet.
Description
Participants will first come for a screening visit one time, lasting a total of 2.5hours. For this screening visit, each participant will need to fast for 12 hours(go 12 hours without eating from the last meal). During this study visit, each participant will be going through the following tests:
- Urine pregnancy tests (for females)
- Medical History Questionnaire: It will take about 10 minutes, and participants will fill out a 1-page questionnaire about their medical history and medication use
- Each participant will consume a semi-liquid meal within 5 minutes
- Each participant's blood pressure will be measured every 5 minutes before eating, for 15 minutes, and for 2 hours after eating.
After the screening visit, each participant will be coming for study visits on 2 separate mornings, separated by at least 1 week. On these two mornings, the participant will be randomly picked (like the flip of a coin) by a computer to eat the low-glycemic index meal or high-glycemic index meal. After the visit in the morning, the participant will be sent home wearing a blood pressure monitor and blood sugar monitor, along with study meals the participant will be eating for 3 days.
These procedures and tests will be made during these 3-day periods:
At UAB during the morning visit:
- Meal tolerance test: Firstly, a nurse will place an intravenous catheter in the participant's arm to allow blood draws. The participant will be asked to eat the study meal given by the investigators, and provide several blood samples (immediately before and 10, 30, 60, 90, and 120 minutes after glucose ingestion). The total amount of blood taken will be about 3 tablespoons.
- Participant's blood pressure will be measured every 5 minutes before eating, for 15 minutes, and for 2 hours after eating.
After participant goes home from UAB:
- Before the participant leaves for home, the investigator(s) will fit a wearable blood pressure monitor on his/her arm and insert a continuous glucose monitor in the back of the other arm.
- The blood pressure monitors will be programmed to measure blood pressure every 15 minutes during the daytime and hourly during nighttime. The daytime and nighttime cycle will be set according to each participant's sleep/wake pattern. Participants will need to keep the monitored arm steady and at heart level during each blood pressure reading.
- Each participant will be provided with meals for 3 days. They will be eating all and only the meals the investigators provide during these 3 days.
- Each participant will be filling out a checklist to record the time of each meal consumed.
- Each participant will be asked questions regarding their daily activity for the past 3 days for the investigators to estimate their activity level. The investigators will use the Physical Activity Recall Assessment for People with Spinal Cord Injury (PARA-SCI) questionnaire. This takes about 30 minutes and will be done over the phone
Eligibility
Inclusion Criteria:
- Chronic SCI, At least 1 year after injury, Injury level between Cervical 4 and Lumbar 2, with an American Spinal Injury Association (ASIA) Impairment Scale classification of A-D
Exclusion Criteria:
- pregnancy or breastfeeding, type 1 or insulin-dependent type 2 diabetes, a recent change in the use of any medications, previous diagnosis of heart diseases and/or stroke, or neurological impairment other than SCI.