Type 2 Diabetes is a chronic disease associated with poor dietary habits and lifestyle choices. It is common knowledge that diabetes involves abnormal regulation of blood glucose (sugar) but many of us are not aware of the full extent of the health complications associated with the disease.
Diabetes is the leading cause of amputations in Canada, increases the risk for cardiovascular disease, can cause a form of blindness called diabetic retinopathy, and can impair nerve function (diabetic neuropathy) (1). Now it turns out that type 2 diabetes can also affect the brain…
There is an increasing amount of evidence to suggest that type 2 diabetes (2,3) and obesity (4) are linked to cerebral atrophy (basically, shrinking brain), cognitive impairment and dementia. Even more alarming: a recent article found that blood glucose levels higher than normal, but still below the level indicative of diabetes, can negatively affect the brain (5).
To look at the effects of elevated blood glucose levels on the brain, researchers took 249 patients in their early sixties without any signs of brain function impairment and who did not have type 2 diabetes or pre-diabetes; they compared their brains at baseline and four years later. They scanned their brains using an MRI and found that higher blood sugar levels were related to a smaller brain size. Even when they controlled for age, sex, BMI, hypertension, alcohol and smoking, about 6-10% of the change in brain size could be accounted for by the higher blood glucose levels (5).
The areas of the brain they focused on were the hippocampus and the amygdala. The hippocampus has many roles but is most famous for its role in memory; whereas, the amygdala is involved in memory and emotional reactions.
Although the mechanisms are still under investigation, it is believed that the systemic inflammation (continual, non-specific stimulation of the immune system) seen with increased blood sugar levels could play a role. This is because continual inflammation has been associated with a smaller brain, especially the hippocampus (5); indeed, higher blood sugar levels have been linked to poorer memory (6). It is thought that if a person’s blood sugar levels are consistently high it can cause the nerves in the brain to degenerate (7). As an aside, type 2 diabetes also increases the risk of clinical and subclinical strokes, which can also increase brain aging (8).
Not just a concern for adults! Elevated blood sugar levels are also a component of metabolic syndrome (MetS), along with abdominal obesity, high blood pressure, and high cholesterol levels. Recently, obesity and metabolic syndrome have been associated with lower cognitive performance (poorer math, spelling and attention span) in adolescents. These teens also had smaller hippocampal volumes (9).
No Baloney’s advice? Have your blood glucose levels checked regularly, especially if you are overweight, diabetes runs in your family or your levels have been creeping up slowly. Ask your doctor to let you know even if they are on the higher end of “normal” and intervene with lifestyle changes sooner rather than later.
Better yet, be proactive:
- Exercise regularly: 30 minutes a day 5 days a week is a good goal
- Eat whole foods that are lower on the glycemic index: focus on veggies & fruit, whole grains and lean protein
- Watch portion sizes to promote a healthy body weight: stop eating when you are satisified and no longer hungry, not stuffed!
Fortunately, the diet and lifestyle choices that will help reduce your risk of type 2 diabetes are the same diet and lifestyle choices that will reduce your risk of obesity and cardiovascular diseases. Knock them all out with one fell swoop! If you have already been diagnosed with diabetes or pre-diabetes you can see Health Canada’s website on how to reduce the risk of complications.
- Public Health Agency of Canada. Diabetes Reducing the Risk of Complications; 2009. Accessed September 7th, 2012 from http://www.phac-aspc.gc.ca/cd-mc/diabetes-diabete/complications-eng.php
- Luchsinger JA. Adiposity, hyperinsulinemia, diabetes and Alzehimer’s disease: an epidemiological perspective. Eur J Pharmacol 2008; 585:119-29.
- Okura T, et al. Association between cognitive function and social support with glycemic control in adults with diabetes mellitums. J Am Geriatr Soc 2009; 57:1816-24.
- Anstey KJ, et al. Body mass index in midlife and late-life as a risk factor for dementia: a meta-analysis ofprospective studies. Obes Rev 2011; 12:e426-e437.
- Cherbuin, N. et al. Higher normal fasting plasma glucose is associated with hippocampal atrophy: The PATH study. Neurology 2012; 79:1019-26.
- Dahle CL. Aging, vascular risk, and cognition: blood glucose, pulse pressure, and cognitive performance in healthy adults. Psychol Aging 2009; 24:154-162.
- Levi M, et al. Inflammation and coagulation. Crit Care Med 2010; 38:S26-S34.
- Darvall KA, et al. Obesity and thrombosis. Eur J Vasc Endovasc Surg 2007; 33:223-233.
- Yau PL ,et al. Obesity and metabolic syndrome and functional and structural Brain impairments in sdolescence. Pediatrics 2012; epub ahead of print.DOI:10.1542/peds.2012-0324