A link between sugar and dementia?

A few years ago, if we’d looked at a graph comparing the rise of both diabetes and Alzheimer’s Disease, we’d have been looking at the same curve. In fact, a theory began to emerge that Alzheimer’s was another form, or stage, of diabetes.

Here’s a page from a 2007 brochure about Alzheimer’s Disease:

Doctors don’t know yet what causes Alzheimer’s disease or exactly how Alzheimer’s and diabetes are connected. But they do know that high blood sugar or insulin can harm the brain in several ways:

  • Diabetes raises the risk of heart disease and stroke, which hurt the heart and blood vessels. Damaged blood vessels in the brain may contribute to Alzheimer’s disease.
  • The brain depends on many different chemicals, which may be unbalanced by too much insulin. Some of these changes may help trigger Alzheimer’s Disease.
  • High blood sugar causes inflammation. This may damage brain cells and help Alzheimer’s to develop.

So, ten years later, the picture has changed, in that dementia rates in the US are decreasing, and the age of onset is later—good news. From a NY Times article: “The new study found that the dementia rate in Americans 65 and older fell by 24 percent over 12 years . . . . In 2000, people received a diagnosis of dementia at an average age of 80.7; in 2012, the average age was 82.4.”

But although the data is pretty convincing, no one yet knows what caused the changes. One theory is that the difference may be due to better management of diabetes. A brand new study has found a possible link between diabetes and Alzheimer’s: glucose in the blood binds to and inhibits an enzyme called macrophage migration inhibitory factor (MIF), which is part of a normal immune response to a buildup of abnormal proteins in the brain.

In other words, sugar in the blood inhibits a normal immune system response to abnormal proteins that could be involved with developing Alzheimer’s Disease.

Although I have strong opinions about the importance of eating real food and avoiding processed food, I also recognize that many people lead healthy and happy lives without being anywhere near so strict about what they eat, or perhaps more to the point, what foods they avoid. But to me this development reaffirms the need to be careful about sugar.

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