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chromosomes with telomeres highlighted

The likelihood of developing type 2 diabetes increases as people get older, with common evidence-based screening tools indicating that people over the age of 35 years are at increased risk. There are many potential reasons for this that most people are familiar with, like the gradual weight gain that affects many of us once we reach our full adult height in our late teens to mid twenties. Specifically, if the extra weight gained is in the form of fat around the liver and pancreas (known as intra-abdominal fat). However, most people are probably not aware that shortened telomeres are associated with the risk of developing type 2 diabetes and common diabetes-related complications.

What are telomeres?

To help explain, we need to recall that deoxyribonucleic acid, or DNA, is the molecule found inside all of our body’s cells that contains the genetic information responsible for growth, function and reproduction. Chromosomes are protein structures found within the nucleus of each cell that contain DNA. A bit like those plastic tips on the ends of your shoelaces, telomeres prevent the ends of the chromosomes from fraying. In more scientific terms, telomeres protect the integrity of information carrying throughout each cell cycle by serving as specialized DNA caps on chromosomes. During successive cellular divisions, telomeres prevent base pair loss of chromosomal DNA. Over time, telomere length decreases until the telomere becomes too short for the cell to divide, eventually resulting in the death of the cell. Perhaps unsurprisingly, there is an inverse association between the length of telomeres and biological ageing. In other words, the shorter your telomeres, the greater your biological age.

Telomere length and diabetes

A recently published systematic review has investigated the relationship between the shortening of telomeres and diabetes.
In observational studies conducted in Asia, Europe and North America, people with shorter telomeres are found to have an increased risk of developing type 2 diabetes, independent of other known diabetes risk factors. It is theorised that telomere shortening may lead to premature pancreatic β-cell death, decreasing β-cell mass and subsequently reducing insulin secretion and glucose tolerance.

In people with existing diabetes, observational studies also indicate that shorter telomeres are associated with common diabetes complications like heart disease and stroke. Oxidative stress plays an important part in telomere shortening in people with diabetes. Oxidative stress is increased by high blood glucose levels. Furthermore, advanced glycation end product generation, enhanced glucose auto-oxidation and activation of protein kinase-C and polyol pathways also play a vital role in raising oxidative stress levels. This increased oxidative stress level speeds up telomere shortening.

The good news is that healthy eating guidelines for preventing and managing type 2 diabetes that help people to optimise their blood glucose levels, like consuming a moderate amount of low GI carbohydrate at main meals, and eating plenty of non-starchy vegetables and low GI fruit, will also help slow the shortening of telomeres, in-part by reducing oxidative stress.

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Dr Alan Barclay, PhD, is a consultant dietitian and chef with a particular interest in carbohydrates and diabetes. He is author of Reversing Diabetes (Murdoch Books), and co-author of 40 scientific publications, The Good Carbs Cookbook (Murdoch Books), Managing Type 2 Diabetes (Hachette Australia) and The Ultimate Guide to Sugars and Sweeteners (The Experiment Publishing).
Contact: Follow him on Twitter, LinkedIn or check out his website.