Statisticians have been telling us how Western societies are facing a tsunami of people developing dementia and Alzheimer’s over the next couple of decades. This is associated with our ageing population; we are all living longer, so our relative risk of developing dementia rises as well.
What worries me though is the fact that we seem to be ignoring the impact that the dramatic increase in people living with Type 2 diabetes and obesity will have on these figures.
Both diabetes and obesity are known risk factors for dementia. Adults who develop diabetes before the age of 65 have twice the risk of developing dementia compared to non-diabetics and also have an increased risk of depression.
It is our children that worry me the most. Twenty years ago the number of kids diagnosed with Type 2 diabetes was in the order of 2%. It was an extremely rare condition. Now 30 to 50% of all those diagnosed with Type 2 diabetes are between the ages of 9 and 19 years. Those aged in their thirties, have seen a 70% increase in the number of people diagnosed. The scary thing also, is that it is known that there are an even greater number of people with undiagnosed diabetes in the general population.
What is Type 2 diabetes?
When we eat a meal, the carbohydrates in it are broken down and released into our blood stream as sugar, leading to an increase in the blood sugar level. This then stimulates the pancreas gland to release insulin hormone which works to restore the blood sugar level back to normal by sending the glucose to tissues that need it for energy, or for storage. If the body is repeatedly overloaded with excess glucose, the body’s ability to respond to the insulin is diminished, leading to a condition called insulin resistance. Increasing amounts of insulin then get produced, but it can no longer exert its effect. This is the condition of Type 2 diabetes where blood sugar levels are consistently too high and associated with elevated insulin levels.
It is distinguished from Type 1 diabetes where the specialised glands in the pancreas are unable to produce insulin.
When are we going to wake up to this risk?
If you have diabetes, you have a higher risk of cognitive decline and dementia.
In a study of 2300 older women aged 70 to 78, non-diabetics on mental testing scored twice as high as diabetics. It was also found that the longer the person had had diabetes, the more poorly she performed.
In another multiethnic, multicenter study of 10,000 people, the results of cognitive tests taken 6 years apart were compared. In the 40 to 70 year age group, diabetes was again linked to greater cognitive decline.
What does diabetes do to the body and brain?
Diabetes affects multiple organs in the body including the blood vessels, heart eyes, brain and kidneys and is insidious in how it gradually erodes cognitive ability. Elevated blood sugar levels contribute to hardening of the arteries, (atherosclerosis) which increases the risk of heart disease and stoke. In the brain, this vascular damage is linked to an increase in small infarcts (injury to small arterioles in the brain) or tiny strokes. Having persistently elevated blood sugar contributes to damage of our brain cells, brain atrophy and cognitive impairment. The loss of brain cells is especially prominent in the area of the hippocampus, the specialised brain area concerned with memory and learning. Diabetic patients who have developed diabetic retinopathy have been shown to have twice the risk of developing cognitive impairment.
Excess insulin also contributes to the brain damage. It has been discovered that the brain has it’s own insulin receptors. Increased insulin levels have been linked to increased levels of amyloid, the protein associated with plaques found in Alzheimer’s. Excess insulin also has a role in stimulating inflammation, and reducing the levels of acetylcholine an essential neurotransmitter for memory.
But it’s not just diabetics who are at risk of impaired brain function and reduced mental performance. It has been shown that drinking a sugary glucose drink will adversely affect your ability to perform memory tests. So the key is to avoid big swings in blood sugar levels.
Because we know that diabetes is associated with an increase risk of cognitive impairment and dementia, it is vital that the message gets out to all those at risk.
The good news though, is that we know that good lifestyle choices can have a hugely beneficial effect on blood sugar control.
The aim is to
• Keep blood sugar levels in the normal range • Maintain a healthy body weight • Eat a nutritious and brain healthy diet low in saturated fat • Exercise for 30 minutes a day by walking or other moderate intensity activity.
My question to you is this. Can we afford not be taking immediate steps to educating people to fully understand the consequences of “accepting” the recent global increases in obesity and diabetes?
Our sweet tooth is killing our brain.
Refs: Roberts et al. Association of Duration and Severity of Diabetes Mellitus With Mild Cognitive Impairment. Archives of Neurology, 2008; 65 (8): 1066 DOI: 10.1001/archneur.65.8.1066 University of Southern California (2009, January 28). Getting Diabetes Before 65 More Than Doubles Risk For Alzheimer's Disease.