Preventing Alzheimer's Disease with Diet

Image Credit: Shawn Allen / Flickr. This image has been modified.

Preventing Alzheimer’s Disease with Diet

Up to half of Alzheimer’s cases may be attributable to just seven risk factors shown in my video, Preventing Alzheimer’s with Lifestyle Changes, which include diabetes, high blood pressure, obesity, exercise, smoking, depression, and mental exercise; and that’s not including diet because there are so many dietary factors that researchers couldn’t fit them into their model. But, they acknowledged that diet might be another important modifiable risk factor for Alzheimer’s disease. In particular, there is growing evidence that dietary patterns, such as the Mediterranean diet, are associated with lower Alzheimer’s risk, as well as slower cognitive decline, but which constituents of the Mediterranean diet are responsible?

The traditional Mediterranean diet is a diet high in intake of vegetables, beans, fruit, and nuts, and low in meat and dairy. When researchers tried to tease out the protective components, fish consumption showed no benefit, neither did moderate alcohol consumption. The two critical pieces appeared to be vegetable consumption, and the ratio between unsaturated fats and saturated fats, essentially plant fats to animal fats.

In studies across 11 countries, fat consumption appeared to be most closely correlated with the prevalence of Alzheimer’s disease, with the lowest fat intake and Alzheimer’s rates in China to the highest fat intake and Alzheimer’s rates in the United States. But this is grouping all fats together.

Harvard researchers examined the relationships of the major fat types to cognitive change over four years among 6,000 healthy older women, and found that higher saturated fat intake was associated with a poorer trajectory of cognition and memory. Women with the highest saturated fat intake had 60 to 70% greater odds of worse change on brain function. The magnitude of cognitive change associated with saturated fat consumption was equivalent to about six years of aging, meaning women with the lowest saturated fat intake had the brain function of women six years younger.

What if one already has Alzheimer’s, though? Previously, a group of Columbia University researchers reported that eating a Mediterranean-style diet was related to lower risk for Alzheimer’s disease, but whether a Mediterranean diet—or any diet for that matter—is associated with the subsequent course of the disease and outcomes had not been investigated, until now.

In a study highlighted in my video, Preventing Alzheimer’s Disease with Diet, researchers found that adherence to the Mediterranean diet may affect not only risk for Alzheimer’s disease, but also subsequent disease course, as higher adherence to the Mediterranean diet was associated with lower mortality. And the more they adhered to the healthier diet, the longer they lived. Within five years, only 20% of those with high adherence died, with twice as many deaths in the intermediate adherence group. In the low adherence group, within five years, more than half were dead, and by ten years, 90% were gone. By the end of the study, the only people still alive were those with higher adherence to the healthier diet.

For more on the Mediterranean diet, check out:

I do have a bunch on dietary factors in cognitive decline, though:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of DeathMore Than an Apple a DayFrom Table to Able, and Food as Medicine.


Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.

34 responses to “Preventing Alzheimer’s Disease with Diet

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  1. My understanding is that the Mediterranean diet which was originally studied as being so healthful was from Crete shortly after World War II. The people of Crete had few animals in their diet and olive oil consumption was actually quite low after all the shortages, deprivation and destruction of the war. They grew most of their own food and tramped many miles up and down steep hillsides as a normal part of each day, going and coming, perhaps to grazing grounds for sheep and goats. Does anybody know if this is true? It makes much more sense to me than using the term Mediterranean diet as an excuse to pour olive oil all over white pasta and bread while drinking red wine.

      1. Thanks, Thea. Most people in the general population don’t appear to have this awareness. Based on the video you linked, the diet is similar to that followed in the Mediterranean Blue Zones today.

        1. ron: Interesting question. I don’t think I’ve heard Dr. Esselstyn specifically address omega 3 supplementation. But I’ve heard him talk several times and read his book and have thought about the issue in general. So, here’s my thoughts:
          First, did you really mean to say fish oil? Because Dr. Esselstyn definitely would not recommend that. As shown here on NutritionFacts, fish oil is too often contaminated in significant/harmful amounts. Also, fish do not make omega 3. They get it from their food, just like we do. So, why not skip the middle person and get it directly from the algae? You can buy algae-based DHA/EPA that is grown in vats in factories. It is free of contamination. It does not destroy our oceans. It’s ethical.
          But that still does not address the question of Dr. Esselstyn’s famous mantra: “NO OIL!” from a health perspective. (Isn’t it funny how we all write his directive in all caps?) Even if our omega 3 supplement comes from algae, it’s still oil. It’s still an extracted, pure fat. Could Dr. Esselstyn have meant to include algae based omega 3 supplements also? I would approach it from a different question: Dr. Esseslstyn tells us “NO OIL!” because he has seen evidence from a couple different angles that consuming oil causes harm – either progressing heart disease or directly damaging the lining of our arteries. Dr. Greger suggests that we might take omega 3 supplement because it could help our brains even if it does nothing for our hearts. Would helping our brains possibly hurt our circulatory system? Are we in trouble either way?
          Without knowing solid evidence either way, here is how I as a lay person resolve the question: 1) omega 3 is one of the two essential fatty acids. This means we have to get it from our diet. And most people may not be getting enough from their diet when they start to try to eat healthy, but maybe do not go all the way.
          2) While there are some foods we really shouldn’t eat, I would apply the “dose makes the poison” rule to this question. When you take an omega 3 supplement, you are getting about 1/4 teaspoon of oil. That’s a very small amount, and I’m not aware of studies showing that 1/4 teaspoon of omega 3 DHA/EPA hurts our endothelial cells (the lining of our blood vessels)–especially in the context of a person who eats a whole plant food diet and who does not have heart disease.
          3) In response to your question, I did something I don’t normally do. I took out my copy of the next volume of NutritionFacts videos and watched the two upcoming videos on the topic of DHA and omega 3s. From those videos, I would point out that vegans and non-vegans have about the same prevalence of omega 3 deficiency. And there is a test to find out if our bodies have a healthy/ideal amount of omega 3s. So, I think we would all ideally find out what our levels are and then supplement only if necessary, because brains are just as important as hearts and I don’t think 1/4 teaspoon of omega 3 oil is likely to cause harm to the heart.
          4) That said, when a study looks at “vegans”, that probably includes a great many people who are not eating a healthy diet. Many vegans simply refrain from eating meat, dairy and eggs. I think there are very good reasons to believe that a person who is eating a whole plant food diet which consists of both many portions of greens and some ground flaxseed or chia would likely have a body making all the DHA/EPA we need, even as we age. If there is any doubt about our levels, it can be tested.
          So, would Dr. Esselstyn include omega 3s supplements in his “NO OIL!” directive? I would guess, “No”. If you don’t want to get tested and your diet is less than ideal, then take the supplement as insurance. I suspect that “insurance” is the reason Dr. Greger makes his omega 3 supplement recommendation. He doesn’t see it as hurting, and it could help. Getting this insurance might be especially important if you are an older person. (The upcoming video talks about how our bodies have trouble converting ALA to DHA as we get older.) On the other hand, if you eat a truly healthy diet, especially if you can get tested, then I would say that the supplement is likely not necessary.
          What do you think?

          1. Thea, Wow, what a wonderful explained response. Thank you. Since I am not a regular fish eater except some tuna once in a while, that was one reason for Omega 3 DHA. But I am 82 with heart disease, never a heart attack. Had triple bypass 15 years ago for blockage. While my diet has improved considerably, not all plant based but no red meat sometimes chicken or turkey. Of course, even at my age, I guess my brain needs omega 3. I will ask my Dr. about the test. I have 2 TBS. most mornings of flax in my smoothie. It’s all so confusing, especially, good fat, bad fat. I just wish I could be a vegan, maybe next lifetime.

            1. ron: re: “While my diet has improved considerably…” I think that’s great. One of my favorite phrases is, “Don’t let perfect be the enemy of the good.” So, you don’t have a perfect diet. You have made improvements. You may not be eating a whole plant food diet yet, but you are only 82. There’s no reason you can’t continue to improve your diet over time to move closer and closer to a healthy diet.

              re: “It’s all so confusing…” I hear you brother! I totally agree on that score. Thanks for your feedback on my answer. To whatever extent I helped lesson the confusion a bit, I’m happy. Bigger Picture: One of the exiting aspects of NutritionFacts is that it helps remove some of the confusion (though I understand there is still plenty of confusion to go around).

              Take care.

    1. To be fair, the Cretan diet then did include a pretty high level of calories from olive oil Unfortunately, the actual Seven Countries data are behind a paywall. However, as reported by Nestle, the slightly earlier Rockefeller Foundation study estimated the proportion of total calories coming from fat in the Cretan diet in he 1950s as about 38% with 29% coming from table oils and fats (mainly olive oil).

      So, olive oil consumption in Crete was in fact actually quite high. However, ascribing the benefits of the Cretan diet to olive oil (or wine, bread and pasta) is a step too far. It was for example a near vegetarian diet and was almost completely devoid of supermarket style processed foods. It included the same low proportion of animal foods (about 7% of total calories) as the diet in mainland Greece at that time but more than twice as much fruit and vegetables, about 38% more pulses, nuts and potatoes, and only two thirds the amount of cereals. And, as you say, exercise may be a factor also.

      Olive oil is not a factor in the Okinawan Diet for example nor does it appear to be an important factor in the diet of 7th Day Adventist. Both are famed for long life and good health. So, it is unlikely that olive oil is an essential or key dietary factor.

    1. “So in this study when people were given chocolate cake made out of flax seed oil or coconut oil we didn’t see much change in inflammatory gene expression, but the cod liver oil cake seemed worse.”
      Chocolate cake made with cod liver oil … oh yummy :)

    2. That is true. We even see a lot of claims that coconut oil and related products are anti-inflammatory.

      However, at least one study demonstrates various inflammatory effects from coconut oil consumption. This study looked at the effect of Macadamia nut oil (MUFA) consumption and coconut oil (medium chain SFA) consumption on relatives of T2D patients REL) and controls (CON):

      “CONCLUSIONS: MUFA and medium-chain SFA elicit similar postprandial circulating inflammatory responses in REL and CON. Medium-chain SFA seems more proinflammatory than MUFA, judged by the gene expression in muscle and adipose tissue of REL and CON.”

      1. Hi Tom, I’ve been reading up on lipofuscin accumulation. Do you know if it correlates to unsaturated fat consumption?
        (I eat a lot of nuts and seeds… I try to avoid coconut oil now since, aside from the calories, I found out I’m heterozygous for MCAD deficiency – kind of rare, but people should probably be aware of the condition before they take MCT oil supplements).

        1. Hi.

          Well, I have seen reports that lipofuscin is produced largely as a result of the oxidation of unsaturated fat and specifically PUFAs. These have been largely on websites of uncertain credibility that quoted old sometimes very old research that may not have met modern standards of methodological rigour. Many (but not all) of the sites I saw gave the impression of being very pro-saturated fat . Wikipedia also states this although the first couple of references it offers are no longer available and the other references do not seem to substantiate this particular claim.

          However, more recent reports in the professional journals state eg “postmitotic cells accumulate a non-degradable intralysosomal substance, lipofuscin, which forms due to iron-catalyzed oxidation/polymerization of protein and lipid residues. ”

          “Lipofuscin formation appears to depend on the rate of oxidative damage to proteins, the functionality of mitochondrial repair systems, the proteasomal system, and the functionality and effectiveness of the lysosomes.”

          Obviously, this is an area where people with this particular issue should seek professional medical advice. My only comment would be that it seems that a wholefood plant-based diet high in fresh fruit and vegetables (and therefore high in antioxidants) which is high in complex carbs, excludes heme iron and is low in protein and fat would seem the prudent course. A diet high in nuts and seeds, on the other hand, contains large amounts of protein and fat which might possibly fuel lipofuscin formation.

          1. Thanks for your reply. I agree. My iron is really low (possibly too low; I can’t donate blood). I really need to cut back on the nuts and seeds. I think part of my problem is that my total caloric intake is low and I find I can tick a lot of my micronutrient boxes with things like pumpkin seeds (magnesium) and almonds. Also, I like them. I’m embarrassed to say that right now I’m at 40% of my calories from fat. What do you think would be reasonable (or the highest reasonable percentage)?

            1. As I wrote earlier, this is really something you need to discuss with you medical advisers who are familiar with your case (rather than some unqualified poster on a website).

              For example, are you actually iron deficient or do you just have relatively low levels of iron? Vegetarians generally have lower levels than meat eaters but this can be an advantage:

              On the other hand, actual iron deficiency can be a symptom of some underlying problem.

              What I will say is that iron deficiency is seldom due to a lack of iron in the diet although some types of vegetarian diets can cause iron deficiencies:
              “An appropriately planned well-balanced vegetarian diet is compatible with an adequate iron status. Although the iron stores of vegetarians may be reduced, the incidence of iron-deficiency anemia in vegetarians is not significantly different from that in omnivores. Restrictive vegetarian diets (eg, macrobiotic) are associated with more widespread iron-deficiency anemia. Western vegetarians who consume a variety of foods have a better iron status than do those in developing countries who consume a limited diet based on unleavened, unrefined cereals. Whereas phytates, polyphenolics, and other plant constituents found in vegetarian diets inhibit nonheme-iron absorption, vitamin C, citric acid, and other organic acids facilitate nonheme-iron absorption.”

              Because you eat lots of nuts and seeds, your current diet is probably relatively high in iron.(as well as being high in fat and protein). But it is not possible to say for certain without knowing your entire diet.

              You should ask your medical advisers about the possible causes of your low iron readings and how/if they relate to your lipofuscin and MCAD deficiency status issues.

              Similarly, in your particular circumstances, the need for fat and/or particular types of fat may be different from that of populations in general. Generally speaking though, the WHO states that diets should contain less than 30% fat (and less than 10% saturated fat)

              The WHO also advises a minimum intake of fat of 15% of total calories – 20% for women of reproductive age (and people with a BMI of less than 18.5)

              That said, the traditional Okinawan diet contained only 6% fat and was reputedly extremely healthy.

              But, as I say, you should discuss these issues with your medical advisers. The information provided here on this site is for general education purposes only. It is not medical advice – and I think that you need specialist advice tailored to your particular circumstances.

              1. Thanks so much for your reply! I would discuss this with my doctor, but I don’t think he would know what to tell me about lipofuscin. He’s a great doctor for what I typically see doctors for – acute problems such as infections and monitoring of biomarkers of chronic diseases. I guess if I were very wealthy, I’d go to one of those anti-aging clinics.

                Now that I think about it, I’m probably okay for iron. I’ve been refused for blood donation due to low hemoglobin, but I think if it were too low generally my doctor would have mentioned it since I have had blood work done and I guess it would have included hematocrit. From my Cronometer data, I apparently take in 11-13 mg of iron / day, which is around 67% of the recommended 18 mg. My top iron sources are whole wheat bread, pumpkin seeds and natto.

                Based on the WHO report I think I will try to get down to 20% calories from fat.

                Thanks again :)

  2. This is so frustrating! The majority of non-vegan doctors come to exactly the opposite conclusion on this question of fat alone. Both groups are citing studies. I wish I had enough time to read every study. They agree on vegetables, nuts, fruits, fermented dairy and non-fermented dairy. If you look at the details, they even agree that whole, intact, sprouted grains except for wheat and corn are good for you. But on fact they are just 100% diametrically opposed, and they just cite different studies. Both groups of doctors say, now the conclusion is obvious,and they are 100% in disagreement with each other.
    John S

  3. Everyone should print up the transcripts of these videos and articles and pass them onto their friends and doctors. If you just send a link, people most of the time will not click on the link because they have a long list of E-mails that they still need to look at. Everybody says they will look at the link later, but they never get around to doing it. But, when you send a hard copy of the transcripts, people are more likely to read it. The nice thing about clicking on the printer button is that it also prints up the references right after the transcript of the message. If we all start doing this we can make a difference in this world and actually have “real” “hope” and “change” and not just some feel good political slogan.

  4. The scary part is the following statement by Dr Greger :)

    “Up to half of Alzheimer’s cases may be attributable to just seven risk factors shown in my video,”

    So half of Alzheimer cases are due to lifestyle, but the other half are due to environment, or genetic, or … for which we have no control?

    1. He did add …. “and that’s not including diet because there are so many dietary factors that researchers couldn’t fit them into their model. But, they acknowledged that diet might be another important modifiable risk factor for Alzheimer’s disease. “

  5. Dr. Greger, these results appear to be exactly opposite those of Bruce Fife who is promoting Ketosis diets and coconut oil to treat inflammation in the brain.

    Can you devote a future video or post to ketosis and inflammation processes? This must be a big point of confusion not just for me but others in your audience.

    Thank you for any consideration.


    —> Meat Increases Risk for Alzheimer’s Disease <—-

    Diet may be the most important risk factor for Alzheimer’s disease risk, according to research published in the Journal of the American College of Nutrition. The author used dietary data from 10 countries and several other studies on diet and Alzheimer’s disease and assessed disease risk for several dietary factors. Consumption of meat increased disease risk the most, followed by eggs and high-fat dairy, while high intakes of fruits, vegetables, and grains reduced the risk for Alzheimer’s disease. Possible mechanisms include increased intakes of metal ions, such as copper, and saturated fat, both prevalent in meat.

    Grant WB. Using multicountry ecological and observational studies to determine dietary risk factors for Alzheimer's disease. J Am Coll Nutr. Published online July 25, 2016.

  7. One of the key issues is the contribution of heme iron and copper to the development of Alzheimers. Heme iron only comes from animal protein and is most closely connect to the formation of the plaques associated with Alzheimers. There is an excellent book called Mindspan where he discusses the research on iron. He does say that eating foods fortified with iron are not a good thing the older we get because we can accumulate too much iron with age. Many of the flours, corn and rice we eat and the cold cereals have added iron. If you are a man over 30 or a woman over 50 (no loss of iron via a period anymore) to go with the organics that do not have any added iron and to look for iron in the ingredient label. Diabetics are at even greater risk for many reasons but one in particular is they tend to have more free iron in the their blood due to the effect of glycation (sugar attaching) of the red blood cells. That free iron is very likely to cause more oxidation of brain cells leading to Alzheimers. Any man over 30 and woman over 50 should also stop taking any MV supplements with copper and iron unless you have been diagnosed with iron deficient anemia.

  8. Dr. Greger. I’m not sure if this is outside of your scope, but would you consider making a video on oxidative stress caused by elevated homocystine levels? I believe this is influenced by methianine consumption but also significantlly influenced by by genetic issues with methylation. For myself I have seen enormous improvement in mood from specific supplimentation to compensate for certain gnetic mutations. I believe this issue, related to mood and excessive homocystine is a significant issue in the population and would benefit from your attention.

  9. Doesn’t the type of saturated fat matter? Read about how Dr. Mary Newport turned her husband’s Alzheimers around with coconut oil. Check out the clocks he drew before and after.

  10. Dr Greger, my 60yo sister was diagnosed with early onset Alzheimers at 57. 3 years older than me… there is no other known history of EOA in our family but she has suffered from Ulcerative Colitis for 30+years and has had a bag (and her rectum removed) many years ago. She has still had to take up to 3 gastrostop pills a day though and I cant help but wonder if her EOA came as a result of nutrients being poorly absorbed all these years… she is otherwise very fit and active for her age.
    She has been vegetarian for 3 years for ethical reasons mainly. I am vegan now for 5. I have researched ways to support her with her diet especially but as she has been put on a LOw Residue (low fibre) diet for the problems associated with her gut, it makes gettting plentiful healthy whole foods in to her difficult.
    Any advice will be gratefully received.
    ALso I had signed up to Dr Perlmutter’s website but his anti grain and legume stance, plus being pro meat to prevent alzheimers confounds me!!! Can anyone shed some light on the “Grain Brain” Dr? He seems very well respected but the info is totally opposite from what I have come to understand…

    Many thanks for your work, I recommend your book, website and often your app, to all my clients and guests and friends.

    1. Lifematters: How nice to hear about your efforts to help your sister. I forwarded your post onto our medical moderators in the hopes that someone will have some ideas for you. The part I can help with is your question about Perlmutter. I think the following to links will help you get some perspective: and
      Best of luck to both of you.

  11. How do you reconcile recommending the Med. diet with its emphasis on olive oil when you discourage using olive oil because of artery damage. Because of your opinion, I quit using olive oil completely and either sauté with water or avocado oil. Thanks!

  12. Hello Laura, and thank you for your question,

    I am a family doctor with a private practice in lifestyle medicine and also a volunteer for this website. As noted in the above article, Dr. Greger has done a whole series of videos about the Mediterranean diet. Here is one which talks about how one can improve on the Mediterranean diet:

    It turns out that the parts of a Mediterranean diet which help prolong life and decrease risk of strokes and cerebrovascular disease (presumably including Alzheimer’s) are whole plant foods, including especially nuts. See this video:

    One of the major conclusions of these videos is that, compared with a “Standard American Diet”, the Mediterranean diet is a major improvement, so for most Americans, switching to a Mediterranean diet would be a good idea.

    However, virtually all oils impair endothelial cell function to some extent. Here is a video where Dr. G compares the effects of various oils on artery function:

    In summary, if you’re already eating a whole foods plant-based diet, and are worried about Alzheimer’s and/or cerebrovascular disease, then cutting back on oil is probably a good idea. But if you are switching from eating animal fat to olive oil, that will also help!

    Health Support Volunteer for

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