“How to Prevent Alzheimer’s With Diet” What is behind the dramatic
increase in dementia in Japan over recent decades? Maybe it’s rising obesity rates or the increases in cholesterol,
saturated fat, and iron, or increases in animal products and meat. Overall, calories just went
up about 10% in Japan, whereas animal fat and meat
consumption rose 500%, about 10 times the rise in sugary junk. Now, during this timespan,
rice consumption went down, but the thinking is that rather than white rice
somehow being protective, maybe they were just eating
something worse instead. It’s like when you find fish consumption is correlated with less disease, you wonder if it’s because
they’re eating that rather than some worse meat. If you look across multiple countries, you see a similar pattern, with the most important
dietary link to Alzheimer’s appearing to be meat consumption, with eggs and high-fat
dairy also maybe contributing. There appears to be a
really tight correlation between Alzheimer’s and
per capita meat supply. And, then, studies within
countries uncover similar findings, with Alzheimer’s and cognitive decline associated with meaty,
sweety, fatty diets, whereas most plant
foods were associated with risk reduction. This could be for a variety of reasons. Animal products tend to have more copper, mercury,
lead, and cadmium, and no folate, but contain saturated fat and cholesterol, and pro-inflammatory advanced
glycation end products; so many mechanisms
that dietary modification may be our best bet for reducing risk of
Alzheimer’s disease. But, how do we know
it’s cause-and-effect – the evidence that meat consumption is causally linked to Alzheimer’s disease? Well, there’s the strength
of the association, the consistency across
different types of studies, the fact that the dietary changes preceded the risk of dementia, the dose response— more meat linked to more risk— a bunch of plausible mechanisms. We know that meat is a risk factor for other chronic diseases, but there’s never been
randomized controlled trial to put it to the test. When you read reviews
of the damaging effects of high-fat diets to
the brain and cognition, a number of factors are proposed to account for the high-fat diet-induced damage to the brain. Oxidative stress, insulin
resistance, inflammation, and changes to blood vessels and the integrity of
the blood brain barrier. But, these are based mostly
on studies of rodents. Yes, high fat diets can cause energy dysfunction in the brain, based on fancy MRI techniques, but if you’re looking at
that and thinking that’s a weird looking brain, that’s because those are rat brains. Let me show you two sets
of human cerebral arteries, the arteries deep inside your skull. These are the brain arteries on autopsy of non-demented elderly individuals. Here are the arteries
from Alzheimer’s patients, clogged nearly completely shut with atherosclerotic plaque packed
with fat and cholesterol. With CT scans, you can follow this intracranial artery stenosis, this brain artery clogging, over time, and follow the progression
from mild cognitive impairment to Alzheimer’s disease. Those who only had
low-grade stenosis were pretty stable over time in terms of their cognitive function and ability to dress themselves, and other activities of daily living, whereas those with more clogging started slipping over the years. And those who started
out with the most brain atherosclerosis
rapidly went downhill, and twice as likely to progress to full-blown Alzheimer’s. Chronic consumption of
standard Western diets, and rich in saturated
fat and cholesterol, may compromise our
cerebrovascular integrity compromise the blood
vessels in our brain. So, of course, drugs are recommended, “pharmacological modulation”
of diet-induced dysfunction. But why not just try to eat healthier… in the first place? Video source: https://www.youtube.com/watch?v=t-noCw4LsY4
