Big trouble lies ahead if Alzheimer’s is proven to be a form of diabetes
THE human brain evolved to seek out foods high in fat and sugar. But a preference that started out as a survival mechanism has, in our age of plenty, become a self-destructive compulsion.
It is well known that bad diets can trigger obesity and diabetes. There is growing evidence that they trigger Alzheimer’s disease too, and some researchers now see it as just another form of diabetes (see “Food for thought: Eat your way to dementia”).
If correct, this has enormous, and grave, implications. The world already faces an epidemic of diabetes. The prospect of a parallel epidemic of Alzheimer’s is truly frightening, in terms of human suffering and monetary cost.
This outcome will not be easily averted. Few people need to be told that too much high-fat, high-sugar food is a health hazard. And yet sales of fast food remain healthy (or should that be hefty?). Part of the reason is “future discounting”, another evolved feature of the human brain that makes us value short-term rewards over long-term risks.
What can be done? One option is to call in the lawyers. Some moderately successful attempts have already been made to sue food companies for their role in creating the obesity epidemic. If a causal link between fatty, sugary food and Alzheimer’s can be established, it is highly likely that more lawsuits will follow. Such actions have their place, but this is a laborious and expensive way to enact change.
Nor do the policy levers at our disposal appear promising. Public awareness campaigns have been of limited use in reversing the tide of obesity. Will the added threat of dementia prove harder to ignore? “Sin taxes” on unhealthy foods may work – Denmark and a handful of other countries are experimenting with them – but it is not yet clear whether they make any real difference. What’s more, they raise questions about personal responsibility and nanny-statism.
We may be left with only the option of medically blocking either the craving for fast food, or its consequences. That has its own complications, and sidesteps the problem rather than addressing it. But the human brain also evolved to find ingenious solutions to intractable problems. It may yet come to its own rescue.
Diabetes and Alzheimer’s disease are connected in ways that still aren’t completely understood. While not all research confirms the connection, many studies indicate that people with diabetes — especially type 2 diabetes — are at higher risk of eventually developing Alzheimer’s disease. – mayoClinic
High levels of the hormone insulin, brought on by a bad diet, may harm the brain in the same way that the muscle, liver and fat cells are affected by type two diabetes. Exposing the brain to too much insulin could cause it to stop responding to the hormone, hampering our ability to think and create new memories and ultimately leading to permanent damage, researchers said.
A diet high in fat and sugar has long been linked to a higher risk of Alzheimer’s, while studies of health among large populations have shown that a healthy Mediterranean diet may offer some protection. In type two diabetes, eating too much fatty and sugary food raises our insulin levels to such a consistently high degree that our muscles, fat and liver cells are no longer affected by the hormone.
This means that the amount of glucose and fat in our blood is allowed to increase unchecked, forcing the pancreas to produce even more insulin to try to cope. Ultimately it becomes exhausted and production drops to very low levels. A small-scale trial on human patients at Washington University found that those who were given a nasal spray containing insulin were better at remembering details of stories, had longer attention spans and were more independent.
A further trial on 240 volunteers showing early signs of dementia will provide further clues as to whether the spray can protect memory and learning ability and keep track of brain changes in patients. A study on rats by experts from Brown University suggest that a similar process could affect the brain, which relies on insulin to regulate nerve signals related to memory and learning and to produce energy from glucose.
Researchers found that blocking insulin from rats’ brains made them disorientated and unable to find their way out of a maze because they could not remember where they were. Examination of their brains showed the same pattern of deterioration seen in Alzheimer’s patients, including increased levels of the amyloid plaque which is a key hallmark of the condition.
If the theory is correct, it means eating more healthy foods and exercising more could reduce the risk of Alzheimer’s, and potentially reverse or slow down the memory loss in patients with the condition.