Scientists have spent decades researching an explanation for Alzheimer’s, a disease that causes memory loss and a loss of other cognitive abilities, including thinking and behavior. According to the Alzheimer’s Association, nearly 6 million Americans are living with Alzheimer’s, with that number projected to rise to 14 million by 2050.
And while there are a number of hypothesis out there as to what causes Alzheimer’s—including inflammation, a buildup of amyloid-beta (a protein fragment) deposits in the brain or the presence of metals such as copper, zinc and aluminum—Edward Blonz, Ph.D., assistant clinical professor in the Department of Clinical Pharmacy at the University of California, San Francisco, has put forth a new hypothesis.
In a Q&A with Berkeley Wellness, Blonz explains that all the theories thus far are based on correlations, or “factors present when Alzheimer’s disease is already occurring. Getting a handle on causation has been elusive.”
Blonz’s theory asserts that the development of Alzheimer’s may occur due to a lack of glucose in the brain, which is critical to brain function because it is the brain’s main source of energy. Glucose must cross the blood-brain barrier before it can be used as fuel, but as we age, research has found that less and less glucose is able to cross the barrier.
“This is a normal development that occurs even when there’s no disease, no Alzheimer’s,” Blonz explains. “If the situation develops where the brain can no longer get the energy it needs from glucose, the resulting chronic energy deficiency will bring about changes in how the brain operates. My hypothesis is that Alzheimer’s disease is a result of this problem.”
If Blonz’s hypothesis is correct, it’s not a matter of ingesting more carbohydrates to produce glucose in the body but a matter of getting that glucose through the blood-brain barrier, potentially through pharmaceutical treatments or dietary adjustments.
When there is no glucose to provide energy, our body burns fat, producing fatty acids, which cannot pass through the blood-brain barrier, and partially metabolized fats called ketones, which can pass through the blood-brain barrier and act as a source of brain fuel. “Ketones therefore represent an ‘alternate fuel’ the brain can use when glucose is in short supply,” Blonz says.
Another alternative energy source is found through a high-fiber diet, like the Mediterranean diet. “We have also learned that the microorganisms that normally live in our large intestine can ferment dietary fiber into certain short-chain fatty acids that become ketones after they are absorbed into the body,” adds Blonz, who cites that in cultures that prescribe to high-fiber diets, there is a lower incidence of Alzheimer’s.
So what’s next for Blonz and his Alzheimer’s hypothesis? “The first step must be to stop the underlying energy problem that causes the amyloid-beta to form in the first place,” he says. “If we can assure that the Alzheimer’s brain begins to get the energy it requires, this may increase the effectiveness of the treatments we’re using. Once you have that under control, existing treatments might actually start to become more effective.”
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