As the body becomes more and more overweight, it becomes more and more resistant to the blood-sugar-lowering effects of insulin. To counter this insulin resistance, the body keeps making more insulin. If it continues, this escalating cycle of insulin resistance and insulin production end in type 2 diabetes.
It is over time, as insulin is increasing to keep up with the demand on the body and the ever increasing insulin resistence that inflammation comes into play. You may remember I wrote recently about the detrimental effects of inflammation in the body.
Inflamed tissues send off chemical warning signals. These warning signals set off an avalanche of tissue-damaging effects. But insulin doesn't just cause inflammation in the lower body. It also causes inflammation in the brain, find University of Washington researcher Suzanne Craft, PhD, and colleagues. One dangerous effect of this insulin-caused brain inflammation is increased brain levels of beta-amyloid. Beta-amyloid is the twisted protein that's the main ingredient in the sticky plaques that clog the brains of people with Alzheimer's disease.
So just how bad is high insulin? That is the question researchers wanted to try to answer, so they recruited 16-volunteers, aged 55 to 81, who agreed to allow the researchers to infuse their system with glucose and insulin for two hours to measure the short-term effects through spinal tap analysis. The results were startling!
Just this brief rise in insulin levels had what Craft calls "striking" effects:
- It set off inflammation in the brain.
- The spinal fluid had increased levels of a compound called F2-isoprostane. Alzheimer's patients have unusually high brain levels of F2-isoprostane.
- Brain levels of beta-amyloid increased.
Each day millions of Americans engage in a similar experiment (minus the spinal tap) with their bodies - they're overweight, have the start of insulin resistance or are already insulin resistant and eating in a way that maintains high levels of insulin in their bodies.
Because they are overweight and inactive -- and because they may have genetic risk factors -- many people have high insulin levels. It's not good for their hearts. And it's not good for their brains, says Samuel Gandy, MD, PhD.
"Controlling blood sugar and body weight -- all those things we know are good for your heart health are also really good at preventing Alzheimer's disease. So there are more and more reasons not to be slouchy about getting these things under control."
Controlling blood sugar, and thus insulin levels, is much easier if you're controlling your carbohydrate intake by eating real, whole foods, and engaging in activity each day. In the US we have a problem with over-consumption of carbohydrates, especially refined carbohydrates. Our bodies are not designed to effectively metabolize the level of refined carbohydrate we currently eat. Simple modifications in your daily menu can mean big changes in how your body works - and how nimble your brain is!