Wednesday, December 16, 2009

Fat Head More On Alzheimer’s

Fat Head More On Alzheimer’s

First, statins: If you want to delve into the chemistry of how statins affect brain function, you can read this article. In the meantime, here are a few highlights:

There is a clear reason why statins would promote Alzheimer’s. They cripple the liver’s ability to synthesize cholesterol, and as a consequence the level of LDL in the blood plummets. Cholesterol plays a crucial role in the brain, both in terms of enabling signal transport across the synapse and in terms of encouraging the growth of neurons through healthy development of the myelin sheath. Nonetheless, the statin industry proudly boasts that statins are effective at interfering with cholesterol production in the brain as well as in the liver.

Researchers are only recently discovering that both fat and cholesterol are severely deficient in the Alzheimer’s brain. It turns out that fat and cholesterol are both vital nutrients in the brain. The brain contains only 2% of the body’s mass, but 25% of the total cholesterol. Cholesterol is essential both in transmitting nerve signals and in fighting off infections.


The bottom line: your body makes cholesterol for a reason. Beat down your cholesterol with a drug, and you’re messing with your biochemistry at the cellular level. Not a good idea.

Of course, plenty of people who don’t take statins develop Alzheimer’s as well. I doubt statins are a major cause of the disease. But insulin resistance could be.

As Gary Taubes explains in Good Calories, Bad Calories, since neurons in the brain ideally last for a lifetime, they may be prime candidates for the accumulation of advanced glycation end-products, or AGEs — proteins linked haphazardly with sugars. (The acronym is convenient if not intentional; AGEs literally age your tissues.) AGEs appear to be involved in the early stages of the amyloid plaques that form in the brain. That means the foods that spike your blood sugar are already causing trouble. As an article on AGEs and diabetes explains:

A lowered glucose concentration will unhook the sugars from the amino groups to which they are attached; conversely, high glucose concentrations will have the opposite effect, if persistent.

And of course, when you spike your blood sugar, your body spikes its insulin output in response. If you become insulin resistant, your insulin will be high all the time — which in turn inhibits your brain’s ability to clear away plaques. As Gary Taubes wrote:

Insulin (in a test tube) will monopolize the attention of insulin-degrading enzyme (IDE), which normally degrades and clears both amyloid proteins and insulin from around the neurons. The more insulin available in the brain, by this scenario, the less IDE is available to clean up the amyloid, which then accumulates excessively and clumps into plaques … Mice that lack the gene to produce IDE develop version of both Alzheimer’s disease and Type 2 diabetes.

Good article from the creator of the movie Fathead on how cholesterol is good for the brain and carbs are bad. Highly recommend his movie, by the way. You can see some clips on search for fathead movie

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