Professor Jennie Brand-Miller answers your questions
Many of the studies you write about in GI News talk about ‘insulin resistance’ and ‘insulin sensitivity’. Can you explain these terms?
Insulin is a hormone that plays several critical roles in our health and wellbeing. It’s been called the MASTER hormone because it regulates so many things, including our blood glucose levels. When we eat carb-rich foods like bread, breakfast cereals, pasta, rice or noodles, starchy vegetables like potatoes and fruit, our body converts them into a glucose (a sugar) that is absorbed from the intestine and becomes the main fuel that circulates in our blood. When glucose levels in the blood rise after a meal, the beta cells in the pancreas shoot insulin out into the blood to drive the glucose into the cells so it can be put to work either as an immediate source of energy or converted to glycogen (a stored energy source), or to fat.
If you require relatively normal or low levels of insulin to process your BGLs (blood glucose levels), you are what’s called ‘insulin sensitive’ – a good thing.
Insulin resistance, on the other hand, means that the body does not react in a normal way to insulin in the blood. It is insensitive, or ‘partially deaf’, to insulin. Think of it like this: just as we may shout to make a deaf person hear, the body makes more insulin in an effort to drive glucose where it’s supposed to go. So moving glucose into cells necessitates the release of large amounts of insulin.
A healthy low GI diet plus physical activity are the most powerful ways you can optimise your insulin sensitivity and decrease insulin levels over the whole day. The latest paper from the Diogenes study published in the New England Journal of Medicine shows that an ‘increase in dietary protein and a reduction in GI content over a 6-month ad libitum dietary intervention are related to a lower drop-out rate and produced favourable effects on glycaemic control and insulin sensitivity in overweight/obese subjects after an initial body-weight loss.’
GI testing by an accredited laboratory North America
Dr Alexandra Jenkins
Glycemic Index Laboratories
20 Victoria Street, Suite 300
Toronto, Ontario M5C 298 Canada
Phone +1 416 861 0506
Research Manager, Sydney University Glycemic Index Research Service (SUGiRS)
Human Nutrition Unit, School of Molecular and Microbial Biosciences
NSW 2006 Australia
Phone + 61 2 9351 6018
Fax: + 61 2 9351 6022
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