 I'm often asked what my opinion about a diet or disease is. Who cares what my or anyone else's opinion is? All we should care about is what the science says. What does the best available balance of evidence publish to the peer-reviewed medical literature have to say right now? Welcome to the Nutrition Facts Podcast. I'm your host, Dr. Michael Greger. I know so many people who have been diagnosed with Alzheimer's disease, the most common cause of dementia. I bet you do too. In fact, more than 6 million people in the U.S. have it. So how do we avoid becoming one of those statistics? That's a main thrust of my forthcoming book, Hound Not to Age, but in the meanwhile here's a discussion of some little-known risk factors in this, our 300th podcast episode. In our first story, we explore the effect of pesticides on Alzheimer's disease. Although there's a growing list of Alzheimer's disease susceptibility genes, even if you put them all together, they count for less than half of all Alzheimer's cases. The single most compelling piece of data on the potential control we have over the disease is the fact that if you have identical twins with the exact same genes, even if one gets Alzheimer's, the other usually does not. So we have to think about all the other contributing factors beyond just genetics. In my video on pesticides and cancer, I talked about this study. There's a list of chlorinated pesticides, including DDE, a metabolite of DDT, that are classified by the EPA as probable human carcinogens. But in the study, blood levels of DDE and others were associated not with increased cancer mortality, but increased risk of other cause mortality. This led researchers to speculate it may be due to an associated increased risk of diabetes or dementia. I've talked previously about the diabetes link. What about dementia? Elevated serum pesticide levels and risk for Alzheimer's disease. A research team at Rutgers found significantly higher blood levels of DDE and Alzheimer's disease patients compared to controls. And autopsy studies show blood levels are a good proxy for brain levels. Those with the highest levels were at about four times the odds of being demented with Alzheimer's. And in a Petrie, this DDE increases amyloid precursor protein levels in human brain cells, providing a potential mechanism. Put all these studies together, and there does indeed seem to be a link consistent with data showing about a doubling of risk for developing dementia among those acutely pesticide poison. Among U.S. elders, DDT and its breakdown product DDE are also associated with increased risk of cognitive decline in general. DDT was extensively used in the United States from the 1940s to the 60s. At its peak, we were churning out 180 million pounds a year. And it's still in our bodies to this day, contaminating the bloodstreams of more than 90% of Americans. In DDE, the pesticide link to quadrupling the odds of Alzheimer's were at the highest levels. It's still in our bodies because it's still in the food supply. In my last video on the topic, I noted that the levels of DDT, DDE, and other banned pesticides and pollutants were much lower in the breast milk from a vegetarian mother compared to breast milk of a non-vegetarian sister. And the largest difference was noted for DDE, which was four times lower in the vegetarian sister. These toxins build up the food chain, so it makes sense that the most contaminated foods are meat, fish, and dairy products, 5 to 10 times higher levels in meat, eggs, fish, and dairy than what we find in plant foods. And unfortunately, cooking doesn't destroy pollutants like DDE. In fact, it may make them even more concentrated. And this is for a pesticide that may increase the risk of Alzheimer's disease as much as if you carried the so-called Alzheimer's gene, ApoE4. In our next story, we look at the role of meat on Alzheimer's disease. 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 in the iron, from increases in animal products in 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 time span, 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, sweetie, fatty diets, whereas most plant foods were associated with risk reduction. This could be for a variety of reasons. Several products tend to have more copper, mercury, lead, cadmium, nofolate, butt-containing, 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 its 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 meat is a risk factor for other chronic diseases, but there's never been a 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, changes to blood vessels of 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. 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 in 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 enriched 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? Finally today, we look at reducing glyco toxin intake to ward off Alzheimer's. Each of us has about 6 billion miles of DNA. How does our body keep it from getting all tangled up? There are special proteins called histones, which act like spools with DNA as the thread. Enzymes called sirtuins wrap the DNA around the histone spools, and in doing so, silence whatever genes were in that stretch of DNA, hence their name sirtuins, which stands for Silencing Information Regulator. Although they were discovered only about a decade ago, the study of sirtuins has become one of the most promising areas of biomedicine, since they appear to be involved in promoting healthy aging and longevity. Suppression of this key host defense is considered a central feature of Alzheimer's disease. Autopsies of Alzheimer's victims reveal that loss of sirtuin enzyme activities closely associated with the accumulation of plaques and tangles in the brain that's characteristic of Alzheimer's disease. Sirtuins appear to activate pathways that steer the brain away from the formation of plaque and tangled proteins. Because a decrease in sirtuin activity can clearly have deleterious effects on nerve health, they're trying to come up with drugs to increase sirtuin activity, but why not just prevent its suppression in the first place? Glycotoxins in food suppress sirtuin activity. These so-called advanced glycation end products are AGEs. Our modern diet includes excessive AGEs, which can be neurotoxic. High levels in the blood may predict cognitive decline over time. If you measure the urine levels of glycotoxins flowing through the bodies of older adults, those with the highest levels went on to suffer the greatest cognitive decline over the subsequent nine years. As we age, our brain literally shrinks. In our 60s and 70s, we lose an average of 5 cubic centimeters of total brain tissue volume every year, but some lose more than others. Brain atrophy may be reduced in very healthy individuals, and a few people don't lose any brain at all. Normally we lose about 2% of brain volume every year, but that's just the average, although the average brain loss for folks in their 70s and 80s was 2.1%. Some lost more, some lost less, and some men and women lost none at all over a period of four years. Researchers in Australia provided the first evidence linking AGEs with this kind of cerebral brain loss. So, limiting one's consumption of these compounds may end up having significant public health benefits. Because search-win deficiency is both preventable and reversible by dietary AGE reduction, a therapeutic strategy that includes eating less AGEs may offer new strategy to combat the epidemic of Alzheimer's. Some of these glycotoxins are produced internally, particularly in diabetics, but anyone can get them from smoking and eating, particularly foods high in fat and protein. In a previous video, I listed the 15 foods most contaminated with glycotoxins, mostly chicken, but also pork, beef, and fish, which may help explain why those that eat the most meat may have tripled the risk of getting dementia compared to longtime vegetarians. We would love it if you could share with us your stories about reinventing your health through evidence-based nutrition. Go to nutritionfacts.org slash testimonials. We may share it on our social media to help inspire others. To see any graphs, charts, graphics, images, or studies mentioned here, please go to the Nutrition Facts Podcast landing page. There you'll find all the detailed information you need, plus links to all the sources we cite for each of these topics. For a timely text on the pathogens that cause pandemics, you can order the e-book, audiobook, or hard copy of my last book, How to Survive a Pandemic. For recipes, check out my second to last book, My How Not to Diet Cookbook. 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