Science blog points to an article in the Journal of Alzheimer’s Disease [related BBC article] that suggests that Alzheimers results from neural tissue being unable to properly respond to or produce insulin. In effect, the researchers say, Alzheimers may be a form of diabetes.
If borne out, this research raises an interesting possibility: Could the increased rates of Alzheimers seen in recent decades result from the low-fat, high-carb diets used to treat heart disease in the elderly?
The researchers in the study used a drug to interrupt the ability of the brains of mice to properly use insulin. The mice developed Alzheimers-like damage as a result. The study outcome most closely mimics Type 2 diabetes which is caused by the cells of the body no longer responding to insulin’s signal to take up sugar from the bloodstream. This is termed insulin resistance.
The standard nutritional advice for the last 30 years for those with signs of heart disease has been to follow a low-fat, high-carbohydrate diet. Unfortunately, carbohydrates simply turn to sugar when eaten. Eating a potato or a cup of pasta has pretty much the same effect on blood-sugar levels as eating the same weight in table sugar.
Reduced calorie, low-fat diets have a positive impact on weight and diabetes. However, many people on low-fat diets simply substitute calories they once got from fat with calories from carbohydrates. They consume as many or more calories than before and they don’t lose weight. The increased blood sugar from the carbs causes increased insulin levels which can eventually cause insulin resistance.
I can’t help but wonder if in some cases the insulin resistance occurs in the brain and leads to Alzheimers. Be a bit of an oops for the medical community but it wouldn’t be the first time where focusing on treating one particular disease had an unintended consequence for another.