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Anthropometric measurements are body measurements taken during your screening visit. There is often a link between anthropometric measurements and health status. This data will support the information obtained from blood tests during the study.
The HbA1c test is the preferred method for quick, accurate diagnosis of diabetic conditions. Hba1c measures glycated haemoglobin, or the concentration of glucose attached to blood cells. As haemoglobin cells live for approximately 8-12 weeks, this test is able to give a measure of average blood sugar levels over this period of time.
The GLARE study involves the consumption of antioxidant-rich food extracts, namely grape seed extract, rooibos tea extract, and olive leaf extract. In order to determine their potential effect on regulating blood sugar levels, there is a need to refrain from consuming similar foods, or foods that contain similar ingredients. This means that any effects observed during the study can only be attributed to these particular food extracts.
Fasting for at least 10 hours before each visit allows us to measure your baseline blood sugar level. This baseline is used as a comparison to measure the effect of the plant extracts on your blood sugar levels.
You can drink as much water as you like to keep yourself hydrated. Plain water is allowed during your fast from the night before till the morning you come for your study visit.
Alcohol consumption has been shown to abnormally influence blood sugar levels and blood test values and hence abstaining from alcohol consumption for 24 hours before each visit is required.
Undergoing strenuous physical activity the day before your visit may affect the metabolism and regulation of sugars, and may cause abnormalities in blood test results. It is preferable to refrain from all forms of strenuous exercise for at least 24 hours prior to each study visit.
The OGTT drink contains 75g of carbohydrates which, when consumed on an empty stomach will cause your blood sugar level to rise. Anti-oxidant rich plant extracts or a placebo will be taken at the same time as the drink. By monitoring your blood glucose we will be able to see whether the plant extracts play a part in influencing blood sugar levels.
In a healthy individual it usually takes about two hours for blood sugar levels to return to normal after consuming carbohydrates. The OGTT takes two hours so we can examine how your body metabolises carbohydrates and how long it takes to clear sugar from the blood stream.
Cannulation is a technique where a cannula (small plastic tubing) is inserted into one of your veins on your arm to allow sampling of blood.
During the screening visit, you will only do one finger prick test (a few drops of blood) to measure your HbA1c. At each study visit, there will be eight time points when we will take blood from you, 9 ml each time, totalling 72 ml of blood per study session.
Lab tests will be conducted to measure blood glucose (blood sugar), insulin and antioxidant activity. A blood protein analysis will also be done. The information will be used to determine whether antioxidant-rich food extracts that you consume during the study are effective in bringing down your blood sugar to healthy levels.
By participating in the GLARE study, you will be part of finding new and lasting solutions to reduce the risk factors for diabetes. The data obtained from you and the other participants will help us in determining whether antioxidant-rich foods, in particular the grape seed extract, rooibos tea extract, and olive leaf extract, can help in reducing blood sugar levels and improving insulin levels to prevent progression into diabetes. This study will lead to the next research in understanding the underlying mechanisms of how the body makes use of such food extracts to regulate blood sugar levels.
The GLARE study may help to better inform you of your current health status in relation to prediabetes. Any new information obtained from the study will be scientifically published to inform you whether consuming antioxidant-rich food extracts is indeed beneficial in modulating blood sugar levels. You will also learn how clinical studies are conducted to better understand the role of nutrition in influencing healthy dietary pattern and lifestyle.
The GLARE study is clinical nutrition research only. Its purpose is to help determine the potential benefits of antioxidant-rich food extracts in improving blood sugar and insulin levels. It does not replace the need to seek your doctor’s advice on your prediabetic status and managing your condition.
It is always advisable to have a consultation with a medical doctor to obtain information on managing your prediabetic condition.
Page authorised by Head of School, School of Food and Nutrition
Last updated on Tuesday 28 August 2018