Food for Thought, Brain-Healthy Foods with Dr Michael Greger

Voice Over:

Welcome to the NIHR Dementia Researcher Podcast, brought to you by dementiaresearcher.nihr.ac.uk.

Dr Sam Moxon:

Hello, everyone, and welcome back to the Dementia Researcher Podcast and the Food for Thought series. I’m your host, Dr. Sam Moxon, and regular blogger here at Dementia Researcher. Today, I’m joined by New York Times bestselling author and physician, Dr. Michael Greger. Michael Greger is famous for the book How Not to Die, and the corresponding cookbook, How Not to Diet, and next year, he is releasing a new book, How Not to Age, primarily about the best way to prevent dementia with diet and lifestyle. It was a really fascinating discussion and I hope you enjoy it. Michael Greger, welcome to the Dementia Researcher Podcast. How are you today?

Dr Michael Greger:

I am doing so good and I’m so excited to hear that there’s a Dementia Research Podcast.

Dr Sam Moxon:

Yeah, it’s growing as well. It’s really exciting to build this audience, and also, we’re building an audience of people who are interested in food and dementia research. Let me start with my opening question, which I think sets us in quite nicely. What did you eat for breakfast today?

Dr Michael Greger:

Oh, what I ate for breakfast? Oh, God. Okay. What I call groatnola, which is a homemade granola made out of buckwheat groats, mashed sweet potato, and rolled oats. That’s the base. You can add some pumpkin pie, spice powder, whatever. Then you bake it at… Oh, sorry, I don’t know the Celsius. 250 degrees Fahrenheit for one and a half hours, gets nice and crispy, then mix that with berries. Today, I had blackberries, blueberries, and something called autumn olive, which is a native plant, and where I am in Virginia that makes these beautiful little story berries, along with walnuts, pumpkin seeds, a Brazil nut, and some cocoa powder with a little cardamom for flavor and anything else, and then some unsweetened soy milk, and we are good to go.

Dr Sam Moxon:

That sounds great, sweet potato at breakfast because I had sweet potato. At lunch, I had sweet potato and black bean chili. It’s a power food, I think. That little sweet potato.

Dr Michael Greger:

What a perfect meal. Absolutely. I went to med school in Boston, and it was during the winters, what you do is you microwave some sweet potatoes, you put them in your pockets, it’s hand warmers. Then just when they get cool enough, you take them out in nice little healthy snack.

Dr Sam Moxon:

Great. Yeah, it’s delicious sweet potato. I want to start by thanking you for joining us. I’ve been a follower of your work for a number of years now. My story is that I was diagnosed with ulcerative colitis early last year, and my partner was reading How Not to Die at the time and she said we need to try a plant-based diet, and the difference it has made to me has been huge, but it got me down this path of exploring other diseases where diet and lifestyle could be either acutely effective or preventative.

I enjoy your work because the amount of research that goes into anytime you release a short video, anytime you release a bit of content, you always think the studies, and so you’ve done a lot of research into not just dementia but many diseases. If we can focus on dementia, we talk a lot about dementia and lifestyle, and I’ve seen you speaking about your maybe concerns with treating something like say Alzheimer’s disease acutely. The idea that when someone’s diagnosed with Alzheimer’s, a lot of damage is irreversible. Is prevention the best strategy for something like Alzheimer’s disease? If so, how powerful is diet and lifestyle in that sort of equation?

Dr Michael Greger:

Prevention is key. Really, you could say that about pretty much any disease. Certainly, dementia is not… Well, prevention probably is a special case there because there are diseases like hypertension, obesity, type 2 diabetes, that you can’t actually reverse. Even if you get to them early enough, you can actually go from having high blood pressure to normalizing your blood pressure hopefully before you have a stroke or kidney damage or damage to your eyes. Whereas with many types of dementia, this is not all. There are reversible causes of dementia such as B12 deficiency, such as hydrocephalus. You put a drain in, you can reverse dementia rather dramatically. There are few reversible causes of dementia and let me just take a moment to emphasize how critical it is to exclude any and all reversible sources of dementia before being slapped with an Alzheimer’s diagnosis.

Dr Sam Moxon:

You’ve actually just answered one of my questions because I heard your story about your mother, so if you could-

Dr Michael Greger:

Oh, my God. Oh, I’m so glad. Yeah. Can you mind if I say that story really quick?

Dr Sam Moxon:

Yeah, go for it. Yeah.

Dr Michael Greger:

This is just, oh, my God, one of the most tragic and then untragic stories in my life where my mom was diagnosed with not just Alzheimer’s dementia, but Lewy body dementia. It was like Alzheimer’s and fast forward. I got long story. It was, of course, rocked the whole family. Her mom died of Alzheimer’s very horribly and tragically and ugly, and we both actually dealt with that horrible episode, so the thought of my mom going down the same path, which was horribly tragic. Turns out she had the normal pressure hydrocephalus, which causes this dementia symptoms, but you do this amazing test, you do this one of the most dramatic things I’ve ever seen in medicine where what’s happening is this buildup of fluid in the brain and just compresses the brain, and so you have this global cognitive decline.

The way you see of it, actually, is you do a lumbar puncture, a little spinal tap, you draw out a few CCs of fluid just to relieve that pressure, and what happens is all of a sudden you bounce back. My mom went from not recognizing who I was to all of a sudden completely normal with her multiple degrees and brilliance literally within minutes, and then had this Flowers of Algernon in reverse hour after hours, the pressure builds up, and she fades away. All you have to do is put a little shunt in, drain off the fluid, and all of a sudden you are back, but imagine all the people who were diagnosed, and this was multiple physicians, neurologists diagnosed her with this irreversible dementia, either Alzheimer’s, Lewy body disease, in which case what? There’s nothing you can do, essentially, and she would’ve got worse, worse, worse, and then died.

Dr Sam Moxon:

Yeah.

Dr Michael Greger:

So, you just want to make sure that any and all reversible causes are checked before having a diagnosis that still is really largely clinical at this point.

Dr Sam Moxon:

Always get a second opinion. We’ll come back on this a little bit later because I think, first, that’s a great story. It’s great to hear that your mother has recovered from that, and you had, eventually, a positive experience in the end. I think that’s a really powerful story. I’m wanting to talk about the nitty gritty of what we can do to help reduce the risk of those irreversible forms of dementia. The kind that perhaps scares the most because they seem so inevitable in terms if you have it, this seems like there’s not much you can do.

That is true to a point, but we’ve spoken to a number of people now, we’ve spoken to Neal Barnard, Dean Sherzai, and they shared a message, which I think you subscribed to as well, is that there are things we can do to significantly reduce our risk, particularly around vasculature. I’ve heard dementia, sometimes, particularly Alzheimer’s, is called type 3 diabetes because a lot of the same pathologies can persist in the two diseases. Just to let this out to us, what is the best thing we can do in terms of diet and lifestyle to reduce our risk of dementia?

Dr Michael Greger:

Okay. I’ll go back and actually answer the first question, which I realized that I didn’t do.

Dr Sam Moxon:

Well, it’s good to tangent every now and then.

Dr Michael Greger:

Yeah, no. There’s a bunch of different scoring systems for dementia prevention. There’s one that I talk about in my new book, How Not to Age, which should be coming out December 2023, that’s over a year from now, but that found that a 50-year-old man, for example, who didn’t finish high school is physically inactive, obese with high blood pressure and cholesterol, is 50 times, five zero times, more likely develop dementia compared to a 50-year-old who is more educated, active, not obese, normal blood pressure and cholesterol. We have enormous influence on our risk. I’m glad you had on some of those other folks to talk about. You can measure the diameter of the cerebral arteries.

On autopsy, for example, you can see the same kind of atherosclerosis and systemic disease don’t just get in your heart, it gets to your aorta, peripheral vasculature, up into your carotids and into your brain. You can see the same kind of clogging down of blood flow. That means less oxygen to your brain, less removal of waste products, et cetera, which can increase your risk. Also, oxidized cholesterol can clog up in your brain, and so we can associate high LDL cholesterol levels with not just heart disease and not just vascular dementia, which is this mini stroke syndrome, but with Alzheimer’s dementia as well.

Now, this was such an exciting path that Dr. Dean Ornish, who was famous for his lifestyle heart trial of reversing the progression of a coronary artery disease, number one cause of death for men and women with a plant-based diet and lifestyle program, then went on to try to reverse progression of cancer, which did with early stage prostate cancer in men, if that wasn’t a tall enough ladder to climb, is currently underway with a trial for all time. Is it possible that we can take the same diet that prevents the disease and use it to actually treat and reverse it? We know that’s the case for type 2 diabetes, for high blood pressure, for obesity. We can do it for some forms of chronic kidney failure. That’s the recommendation of American Institute for Cancer Research, the same diet that prevents cancer is the one you use to treat it after diagnosis. The question is, is the brain too far gone? Once neurons are dead, we’re bringing them back to life. How exactly does that work?

Dr Sam Moxon:

Yeah, this the big question. I’ve worked a lot in tissue engineering models of dementia, and one of the questions I’ve been asked in the past is, I’ve worked in regenerative medicine in the past and people said, “Well, why can’t you just regenerate the brain?” Well, you can in theory, but once those connections are lost, is the personality lost? Are the memories lost? Will you get the same person back? In terms of reversing, maybe, but what will the person be like after that?

Dr Michael Greger:

Slowing the progression of an invariably fatal disease, I guess it depends at what point you start out with, but if you’re already at a point where you don’t recognize yourself or loved ones in the mirror, is prolonging that state necessarily? What should be the treatment goals? Fascinating question. Look, I have tremendous respect for Dr. Ornish, and it takes some tremendous guts to put on a project like that, I can’t wait to see the results, I’m skeptical, but look, healthy diet can just help. The number one killer of breast cancer patients is heart disease. It actually still is hard to treat because they’re diagnosed so late. Most breast cancer commercials are about young women with ribbons, but most women are diagnosed late in life. Actually, it’s like neck and neck, but heart disease actually overtakes breast cancer as the leading cause. If you don’t want to die with breast cancer, eating a heart healthy diet is kind of ironic, and whether or not that diet helps with breast cancer, it can give you enough time to try more conventional therapies.

Dr Sam Moxon:

Well, obviously we’re not here to talk about breast cancer, but it’s interesting that you mentioned that because I know there are studies showing that things like soy protein can actually… There was always this poor attempt to discredit soy of the protein sourcing it causes breast cancer, but actually, it reduces the risk, studies now suggest so it’s interesting.

Dr Michael Greger:

Right. It reduces risk 30% to 50%, particularly even starting in one’s teenage years, and then many analyses show improved survival and so those women eating soy, had diagnosis, live significantly longer, have significantly lower cancer recurrence rates than women that don’t eat soy, and this is controlling for other factors, though what we don’t have are randomized controlled trials. Though we do have for flax. Flaxseeds, which is another source of these phytoestrogens and different class of phytoestrogens, we do actually have before and after breast cancer biopsies six months of those in a double blonde placebo controlled food study, which is very rare because they baked muffins, so flaxseed versus non-flaxseed muffins, which are evidently indistinguishable and actually was able to show a significant drop in a number of cancer growth markers, those randomized to flax, which is not flax. It’s a very similar phenomenon.

Dr Sam Moxon:

That’s interesting. From what we’ve talked about in terms of dementia, it seems like we’re talking about things like atherosclerosis. It seems like a low-fat diet is a good way to reduce the risk of dementia. It seems fat is a big cause. What about [inaudible 00:14:43]?

Dr Michael Greger:

Let me just push back a little bit then. It’s a low saturated fat diet.

Dr Sam Moxon:

Okay. Yeah.

Dr Michael Greger:

I would also say low trans-fat diet, but trans fats has essentially been eliminated from the food supply, but low saturated fats. For example, nuts are very fatty but would not be expected to increase.

Dr Sam Moxon:

Yeah, so choose avocado, not chips, basically?

Dr Michael Greger:

Right. Yes.

Dr Sam Moxon:

Yeah. Aside from saturated fats, we’ve had a gastroenterologist on, a guy called Dr. Alan Desmond, and we talked about the gut microbiome and the role that gut microbiome may play in dementia, and the way that the foods that we eat can change the microbial diversity and they can potentially release compounds that can be harmful to the brain. Are you familiar with any of this work and how much do you think the gut microbiome plays a role as well? It’s been called the second brain by some people.

Dr Michael Greger:

Yeah. In terms of the neural density. Let me look. That is a great question. I’m going to pull up. I did a microbiome check. My brain is swirling with this new project.

Dr Sam Moxon:

While you pull it up, I can explain what some of the science revealed, and it’s that patients who had predominantly plant-based foods and healthy foods, they basically harbored bacteria in the gut that produced high amounts of compounds like butyrate, and butyrate was shown to be neuroprotective. People who were eating processed, mainly westernized diets, tend to promote the growth of bacteria that can release harmful compounds into the brain and particularly promote the formation of toxic amyloid oligomers in the brain, which can kickstart approaches of dementia, which I found very interesting.

Dr Michael Greger:

We do know TMAO is present in human cerebral spinal fluid. That’s trimethylamine N-oxide, which is formed by our gut microbiome from carnitine and choline found concentrated in red meat and egg yolks. We know that TMAO levels are higher in those with both mild cognitive dysfunction and Alzheimer’s disease, and cause and effect has been established in mice where TMAO supplemented animals that suffer from brain inflammation, impaired learning memory, which is ameliorated by TMAO lowering, but no such causal link has been established in people, though there was a Mendelian randomization studies suggesting those born with a higher genetic predisposition to higher TMAO levels do not appear to grow up with a higher risk of Alzheimer’s disease, so that’s questioning the role of TMAO in human cognitive dysfunction, even though it’s been found such in laboratory models.

Dr Sam Moxon:

Okay, so the other question I wanted to ask you is then if someone’s listening to this and they’re thinking, “Okay, so there is evidence that perhaps what I eat is important in terms of brain health,” if you were to have a patient come up to you and say, “I want to make some dietary changes and I want to try and promote my brain health with the food that I put onto my plate. Can you give me, I don’t know, five foods that I should try and consume either weekly or daily that can help push me towards not just getting my body healthier but getting my mind healthier as well?”, are there any that you would recommend people to consume?

Dr Michael Greger:

The directors of the Loma Linda Alzheimer’s Prevention Program, they have seven key takeaways in terms of diet for dementia prevention. One is reduced processed sugars, so added sugars. Two is reduced saturated fat. Three is reduced animal products, in general. Four, reduced process foods like ultra-processed junk. Number five, some more whole plant foods in general, specifically narrowing out greens and beans, legumes, beans for pastry, peas, lentils. Also, six is increased fruit consumption, not just all fruits, specifically berries, Bradley colored berries. Then seven is reducing the sodium consumption. Those will be the key takeaways. You can see it’s both a combination of reducing animal products, processed foods, and increasing whole plant foods, but not whole plant foods in general, specifically greens, berries, and legumes.

Dr Sam Moxon:

Yeah, that’s great. That’s why I always think it is good to start the day with a bowl of oats with berries and flaxseed, dry seed. It’s a great way to get some of those ingredients ticked off earlier in the day. You can start your day the right way. Now, I also noticed, like we mentioned earlier, you’re on your treadmill at the moment. How important is physical exercise in terms of promoting brain health?

Dr Michael Greger:

I found an old little microbiome section too, if you want me to talk more about that.

Dr Sam Moxon:

We can go back to that and then we’ll come back to the treadmill after that if you want. Let’s go back to the microbiome, revisit the bacteria.

Dr Michael Greger:

Sorry for jumping around.

Dr Sam Moxon:

No, it’s great.

Dr Michael Greger:

There was a remarkable case report published called Rapid Improvement of Alzheimer’s Disease Symptoms Following Fecal Microbiota Transplantation.

Dr Sam Moxon:

This idea fascinates me. It really fascinates me. It’s a strange way of saying, “Eat healthier.”

Dr Michael Greger:

This is cool. The US FDA only allows fecal transplants and clinical medicine for the treatment of recalcitrant infections with a bad bug known as C. diff, but because of that, there’s been a lot of people that have gotten fecal transplants, and so what we see in these kind of serendipitous improvements in these case reports, for example, people who were bald all of a sudden grew back hair after fecal transplant, or improvements in multiple sclerosis. Well, the dementia report involved an 82-year-old man with a five-year history of gradually declining memory and cognition. His mini mental state exam was 20 out of 30, that would be indicating a mild cognitive impairment, but two months after that fecal transplant from his wife, it’s typically family members that are donors, his core MSC score went to 26, which is normal cognition. By month six, he was near perfect score of 29, marked improvement in mood, social interaction, and expressiveness.

It’s case reports like those that make one interested in the field and want to start putting it to the test. What we see is butyrate, for example, which is short chain fatty acid, which is produced from the microbial fermentation of fiber and resistance starts. We’re talking whole grains, particularly whole intact grains, and legumes. Those are the two highest concentrated sources of fiber. They act as prebiotics to create these microbial byproducts like butyrate that then gets absorbed from the colon into your bloodstream circulate throughout your body. We know butyrate does improve the memory function in rats and mice. In Alzheimer’s patients, the microbiomes have been found to have more pro-inflammatory bugs, fewer butyrate producing bugs.

The reason that we think this is not just a consequence of poorer diets among Alzheimer’s patients, well they’re just not eating enough fiber, no wonder they have bad bugs, is because when you transplant stool from Alzheimer’s patients into mice, they have a significant detriment in their cognitive task compared to those fed fecal samples from a non-dementia individual. That suggests there’s something about the microbiome that has a causal influence on cognitive function. There is actually a randomized double blind placebo control trial of fecal transplants for Alzheimer’s disease currently underway, and so stay tuned.

Dr Sam Moxon:

Yeah, really fascinating stuff. Now, I’m interested to talk more. I know you’ve got quite a tight schedule, but let’s quickly touch on the importance of physical activity than intervention, particularly mild cognitive impairment, and that kind of thing.

Dr Michael Greger:

Right. We know that mental performance can be improved across a variety of domains among even modest weight loss, and so the question was, well, wait a second, that there’s a confounding factor of exercise. The American College of Sports Medicine sites meta-analyses of dozens of prospective studies tens of thousands of people for years that does suggest more exercise associated about a 40% lower risk cognitive decline and development of Alzheimer’s disease. Apparently, the more the better. Extra 500 calories expended per week appears to correlate with about an extra 10% drop in dementia risk, but it’s not all or nothing. Even light physical activity like low intensity walking has been associated with cognitive gains in about half of the studies done to date. If indeed the relationship between exercise and dementia prevention is cause and effect, then as much as 20% of all cases of Alzheimer’s disease in Western countries may be attributable to physical inactivity.

That’s more than a million cases of Alzheimer’s just in the US alone, but of course, as with all observational data, there’s a potential for two things, right? Confounding and reverse causation, right? Maybe there’s a shared risk factor causing both, such as atherosclerosis, contributing to both inactivity and dementia or maybe those genetically predisposed exercise has more robust cognitive reserve, though we don’t see that from Mendelian randomization studies. Look, instead of inactivity leading to dementia, you can imagine dementia leading to inactivity, but prospective studies following people over time do show that inactivity precedes the dementia. You can get inactivity 10 years before diagnosis and you see that still that predictive value, though when actually put to the test in interventional trials, increased physical activity and dementia patients increases physical fitness, but disappointingly, no improvement in cognitive impairment. The thought is maybe we’re just not catching people early enough, but interventional trials on dementia patients does not show cognitive improvements, does not necessarily mean exercise. That’s nothing to do with the brain. It may be too late in the disease process.

Dr Sam Moxon:

Okay. I feel it’s just something we could talk about for many, many hours. It’s a topic I’m quite passionate about. I want to just finish by touching on some of your works. Like I said, I’m a fan of your book, How Not to Die. I’ve also got the How Not to Diet Cookbook. The sweet potato African peanut stew is one of my favorite recipes.

Dr Michael Greger:

Oh, great.

Dr Sam Moxon:

It’s very delicious. I know you got, like I said, a new book coming out next year, How Not to Age. Are you able to tell us a little bit more about this? Is dementia going to feature in this book?

Dr Michael Greger:

Oh, my God. Dementia is the single largest chapter. In fact, it could be a book in itself. Yeah. Right now, the whole book is 11,000 citations so it has to be cut way down. It’s about twice as big as How Not to Diet. It’s about a thousand pages and the publisher refuses to publish it, and so I suggested it’d be broken down into multiple volumes. They don’t want to do that, so I have to cut it way back. Unfortunately, it’s not going to be out until December 2023 because months of fact checking, months of editing, got to bring it way down, but yeah, dementia features prominently within the book.

Dr Sam Moxon:

Great. If people want a little bit of a flavor of that, they can pick up How Not to Die and there are chapters in that about the brain as well. Now, I just want to finish with one final question. This topic of diet, lifestyle, and brain health is not controversial, but it is somewhat looked like a suit of science by some individuals. Some people I’ve spoken to, they think, “Oh, it’s not powerful as a prevention strategy.” It’s great to see increased studies now being conducted and showing potential links between the way we live our lives in terms of diet and lifestyle and our brain health. Why do you think it’s taken so long for this to become a little bit more of a mainstream message? Is it just through lack of understanding on our part, or is it a cultural issue, or what do you think the main reason is?

Dr Michael Greger:

Well, I think it’s a culture medicine issue. I think that’s across the board for lifestyle approaches in general. Before Dr. Dean Ornish’s work, a heart disease was considered something that just got worse, worse, worse till you die. Same thing used to be thought of type 2 diabetes, et cetera. Why? Well, where’s the research coming from? The research is coming from largely big pharma, and so you’re looking for lifestyle missing drugs. This is the cash cow because it’s drugs you have to take every day for the rest of your life. This is where the money is. Unfortunately, just no one benefits from having people eat fresh produce because they’re the least profitable foods. They go bad, they rot on the shelf.

There’s perverse incentives on both ends of the equation to not look into this, but if you go back, just look at some of these cross-cultural studies and the fact that rates of many of these chronic diseases, which we associate with aging, inevitably with aging, like raising blood pressures, cognitive impairment, and you realize that the rates of some of these diseases, like colon cancer, et cetera, differ by literally orders of magnitude around the world. When you see that with something like lung cancer, you say, “Ah, well, so it must not be something just genetic about our lungs. Maybe there’s something like smoking that differs from one culture to another,” and so when you see the same thing with colon cancer, breast cancer, or rheumatoid arthritis or dementia, you say, “Wait a sec. Okay, well, it can’t just be an inevitable consequence aging,” and so you have the same research team, there’s research team in Pennsylvania that use the same clinical criteria in places in rural India, for example, to make sure that using the exact same apples to apples criteria, and you see dramatically lower dementia rates.

The lowest substantiated dementia rates in the world are rural India. Also, very low in Nigeria, a place that has one of the highest rates of APOE4, the so-called Alzheimer’s gene. You say, “Wait a second, how is that possible?” It’s because, well, what does APOE4 do? It’s the primary cholesterol carrier in the brain, but if you have diets, they’re low enough in things that would increase cholesterol levels like saturated trans fats and digenetic cholesterol. Well then, yes, genes can load the gun, but it’s environment that pulls the trigger, and we have control over much of that environment. We can protect against head injury, which increase our risk intervention, we cannot smoke, just things we can do to prevent one of the most dreaded diseases of our time. Sixth leading cause of death, Alzheimer’s, got bumped down by COVID to number seven in 2020, but I’m sure it’s on its way back so there’s something we can do. That’s the good news.

Dr Sam Moxon:

It’s the number one cause in England. Well, I’d say I’d like to talk to you about this for hours, but I know you’ve got a very busy schedule. I would encourage our lessons. If you’ve been interested in what you have heard today, you can find Dr. Greger on YouTube and Nutrition Facts. You can find his website, nutritionfacts.org. You’ll find that all the work is heavily researched and backed up with studies. I want to finish by just basically saying to you, Michael, thank you very much for taking the time to join us today. It’s been a really fascinating discussion. Enjoy the rest of your day. To our listeners, thank you for listening and we’ll see you all very soon.

Dr Michael Greger:

You’re all so welcome and thank you so much. Keep up the good work.

Dr Sam Moxon:

Thank you very much. Bye.

Voice Over:

Brought to you by dementiaresearcher.nihr.ac.uk.

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