What evidence is there that our meat-sweet diets play a cause-and-effect role in dementia?
What’s behind the drama? increase of dementia in Japan in recent decades? As you can see at the beginning of my video How to prevent Alzheimer’s with dietprices have climbed significant. Is it due to rising obesity rates or “increases in cholesterol, saturated fat and iron from increases in animal products and meat supplies to Japan”? Overall calories in Japan increased by only about 10 percent, but animal fat and meat consumption increased by 500 percent, about 10 times the increase in sugary junk. During this period, rice consumption declined. Was white rice protective in any way, so is the decrease in intake to blame? Instead, the thought that they ate something worse: “It appears that the link between rice intake and AD [Alzheimer’s disease] in Japan is more likely due to the replacement of rice with animal products.” It’s as if fish consumption is correlated with fewer diseases, so one has to wonder if the decline is actually due to something protective in the fish, or instead the fact that fish just not as bad as other meats.
if you search Across several countries you see a similar pattern: “The most important dietary link to Alzheimer’s appears to be meat consumption, with eggs and high-fat dairy also contributing.” As you can see at 1:02 in my Videothere appears a really tight correlation between Alzheimer’s and per capita meat supply. Studies in different countries have uncovered similar findings, with Alzheimer’s and cognitive decline being linked to meaty, sweet and fatty diets, while most plant-based foods are associated with risk reduction.
This can have various reasons. Animal products tend to be higher in copper, mercury, lead, and cadmium and lack folate, and also contain saturated fat, cholesterol, and inflammatory end-products of advanced glycation. In fact, “there are many mechanisms that link meat in particular, and diet in general, to Alzheimer’s risk,” so making dietary changes may be our best bet to reduce Alzheimer’s risk. But how do we know it’s cause and effect? What is the evidence that meat consumption is causally linked to Alzheimer’s disease? Well, as you can see at 1:49 in mine Video, there are a number of plausible mechanisms: the “strength of the association”, the “consistency of the results” across different types of studies, the fact that the diet change preceded the risk of dementia, and the dose effect of more meat being those at higher risk connected is . We know that meat is a risk factor for other chronic diseases, but there have never been randomized controlled trials to test it for brain dysfunction.
If you read Reviews of the “damaging effects of high-fat diets on the brain and cognition”, “a number of factors have been suggested that cause high-fat diet-induced brain damage, particularly with aging, including oxidative stress, insulin resistance, inflammation, and Changes in vascularization/BBB integrity” — blood vessels and blood-brain barrier integrity — but these are mostly based on studies in rodents. Yes, based on MRI techniques, high-fat diets have been shown to be the case because Energy dysfunction in the rat brain.
What about human brains? At 2:46 in mine VideoYou can see two sets of human cerebral arteries, the arteries deep inside the skull, in autopsy of non-demented elderly versus Alzheimer’s patients. As you can see, the cerebral arteries of people with Alzheimer’s are so clogged with atherosclerotic plaque filled with fat and cholesterol that they are almost completely closed. With CT scans, you can Follow the ICerebral artery stenosis – the blockage of the cerebral arteries – over time and see the progression from mild cognitive impairment to Alzheimer’s disease. As you can see at 3:17 in my Videothe, the had only low-grade stenoses were fairly stable over time in terms of their cognitive function and their ability to dress themselves and engage in other activities of daily living, while those with more severe arterial obstruction began to slip over the years. In contrast, those who started with the most severe atherosclerosis in the brain went downhill quickly and were twice as likely to progress to full-blown Alzheimer’s disease.
“Chronic consumption of SFA-enriched Western diets [saturated fat] and cholesterol Compromise cerebrovascular integrity” – the integrity of the blood vessels in our brain. So, of course, “pharmacological modulation” of dietary dysfunction is recommended, but why not just try eating healthier instead of taking medication?
THE CENTRAL THESIS
- The dramatic increase in dementia in Japan over the past few decades has been linked to an increase in animal products, including meat, and a decline in rice consumption.
- Consumption of animal fat and meat has increased by 500 percent in Japan, while calorie consumption has increased by only about 10 percent.
- Across countries, the consumption of meat, eggs and high-fat dairy products in particular appears to be the “most important dietary link” to Alzheimer’s disease.
- Alzheimer’s and cognitive decline have been linked to diets high in meat, sweets and fat, while most plant-based foods are associated with a lower risk.
- Many factors have been proposed to cause high-fat, diet-induced brain damage, particularly with age, including inflammation and changes in blood vessels and blood-brain barrier integrity.
- At autopsy, the cerebral arteries of Alzheimer’s patients are so clogged with atherosclerotic plaque filled with cholesterol and fat that they are almost closed.
- The standard American diet, high in saturated fat, cholesterol and animal products, has been shown to impair the integrity of the blood vessels in the brain.
This comes as no surprise to those familiar with the scientific record. In fact, I’ve covered similar studies in the past. Cashbox:
In fact, I even debated whether or not I should make this video. For example, when a new broccoli-is-good-for-you study comes out, I just think, I’ve been there. But so many people seem confused about the role of diet and lifestyle in dementia that I thought I’d just cover the latest study, although it didn’t break much new ground.
Michael Greger, MD
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