Image Credit: Angelo Desantis / Flickr. This image has been modified.

Slowing Cognitive Decline with Berries

A plant-based diet is thought to have played a significant role in human evolution and the consumption of whole plant foods and even just extracts have repeatedly been associated with a decreased risk of aging related diseases. And by healthy aging I’m not talking preventing wrinkles, what about protecting our brain? “Two of the most dreaded consequences of dementia with aging are problems moving around and difficulty remembering things. Dementia robs older adults of their independence, control, and identity.”

Fruits and vegetables help reduce the risk of other chronic diseases, so might they work for brain diseases as well?

There has been a proliferation of recent interest in plant polyphenols as agents in the treatment of dementia. There are 4,000 different kinds of polyphenols found ubiquitously in foods of plant origin, but berries are packed with them, possessing powerful antioxidant and anti-inflammatory properties. There’s a subset of polyphenols called anthocyanidins, which are found in blue and purple pigmented fruits and berries. These polyphenols are uniquely and specifically capable of “both crossing the blood–brain barrier and localizing in brain regions involved in learning and memory.” And that’s precisely where we need them.

The brain takes up less than 2% of body weight but may burn up to 50% of the body’s fuel, creating a potential firestorm of free radicals. Maybe these brain-seeking phytonutrients in berries could fight oxidation and inflammation, and even increase blood flow? This raised a thought-provoking idea. Maybe a “nutritional intervention with blueberries may be effective in forestalling or even reversing the neurological changes associated with aging?” It would be a decade before the first human trial was conducted, but it worked! “Blueberry supplementation improves memory in older adults,” suggesting that “consistent supplementation with blueberries may offer an approach to forestall or mitigate brain degeneration with age.”

What other blue or purple foods can we try? Concord grape juice was also tested and had a similar benefit, suggesting that supplementation with purple grape juice may enhance cognitive function for older adults with early memory decline. Why use juice and not whole concord grapes? Because then you couldn’t design a placebo that looked and tasted exactly the same to rule out the very real and powerful placebo effect. And also because the study was funded by the Welch’s grape juice company.

This effect was confirmed in a follow-up study, showing for the first time an increase in neural activation in parts of the brain associated with memory using functional MRI scans. But this brain scan study was tiny: just four people in each group. And same problem in the blueberry study: it had only nine people in it.

Why haven’t large population-based studies been done? Because we haven’t had good databases on where these phytonutrients are found. We know how much vitamin C is in a blueberry, but not how much anthocyanidin—until now. The Harvard Nurses’ Health Study, highlighted in my video, How to Slow Brain Aging by Two Years, followed the cognitive function of more than 16,000 women for years, and found that “long-term consumption of berries was related to significantly slower rates of cognitive decline, even after careful consideration of confounding socioeconomic status” (that is, even after taking into account the fact that rich people eat more berries). The Harvard Nurses’ Health Study was the first population-based evidence that greater intakes of blueberries and strawberries were highly associated with slower rates of cognitive decline, and not just by a little bit. “The magnitude of associations were equivalent to the cognitive differences that one might observe in women up to two and a half years apart in age.” In other words, women with higher intake of berries appeared to have delayed cognitive aging by as much as two and a half years.

Why shouldn’t we just take some anthocyanidin supplement? Because there hasn’t been a single study that found any kind of cognitive benefit by just giving single phytonutrients. In fact, the opposite is true. “Whole blueberries appear to be more effective than individual components, showing that the whole is greater than the sum of its parts.” These findings have potentially substantial public health implications, as increasing berry intake represents a fairly simple dietary modification to test in older adults for maintaining our brain function.

What other ways could we improve our memory and cognitive function?

 What other near-miraculous properties of berries are there?

I add them to my morning smoothie: A Better Breakfast.

-Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my videos for free by clicking here and watch my full 2012 – 2015 presentations Uprooting the Leading Causes of Death, More than an Apple a Day, From 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.

40 responses to “Slowing Cognitive Decline with Berries

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  1. Read this while eating a bowl of oatmeal full of berries! Those 2.5 years are mine! Oh wait, I’m not female. Are there any studies showing cognitive benefits for male berry munchers?

    1. Good point. For men, I would expect similar results. This study discusses how DASH and Mediterranean diets help reduce cognitive decline in elderly men. In particular, nuts, legumes, and whole grains were found to be significatly protective. The authors conclude these foods “may be core neuroprotective foods common to various healthy plant-centered diets around the globe.” Lastly, this study found some associations with certain fruits and vegetables and less cognitive decline. I wonder if berries were responsible? If you are looking for more information on men, check out the 12 videos at the end of this blog post, as so many studies are covered by Dr. Greger. Hope that helps!

  2. What about Indian gooseberries? Or the Amalaki powder derived from them? I take the powder nearly every day in a green smoothie–thanks to Dr. Gregor’s advice.

    1. Indian gooseberries (alma) may help with diabetes. Amla has been extensively studies and found protective for many disorders, perhaps due to it’s high antioxidant capacity?When I searched about cognitive decline only animal studies were available, which doesn’t tell us anything of value for how it works in humans. However, one review mentioned the phytochemicals in alma like quercetin, gallic acid, corilagin and ellagic acid, therefore some logic that this stuff could help reduce cognitive decline may be apparently, but of course we need a human trial to know for sure.

  3. Blueberries and oatmeal, the true breakfast of champions! Unfortunately, organic berries are no longer in my budget, which kinda concerns me since blueberries are listed as one of the “dirty dozen.” I have no choice but assume the benefits outway the risks, as these studies do not specify “organic”, so we can assume they’re not. Once again, why does organic have to be so darn expensive… a rhetorical question of course, my apologies.

    1. No apologies, I agree! Perhaps we all need to forage for berries, collect gallons, and freeze them so we have peak-ripenened berries all the time! Ok, so in a perfect world that may be the case….

      I agree, the benefit of eating conventional berries outweigh the risks of not consuming them. Luckily, Dr. Greger dedicated a huge section of his new DVD to this important question is buying organic worth it? I highly recommend seeing what his new review suggests!

        1. Hmmm I am not sure? Anybody have the answer to that? I think if they don’t say “organic” unfortunately pesticides may still exists, even on a label that says “wild”. Please correct me if I am wrong. I think the only “wild” berries with no pesticides would come from my fantasized idea of walking in a dense forest with a plethora of wild berry bushes :-)

          1. You are right, Joseph. Unless labeled “organic”, wild blueberries are definitely sprayed with both herbicides and pesticides.

          2. I don’t believe all wild blueberries are necessarily organic BUT – I’ve worked with the Wild Blueberry folks and they indicate that the wild blueberries are actually higher in antioxidants than cultivated berries. #goodtoknow! I think they taste better too!

        2. Some could be. Wild blueberries are not cultivated, and not easy to grow. They are smaller, and taste better too. Just last year a big national brand sold frozen wild blueberries which stated right on the label, “grown without pesticides”, not organic, but that was good enough for me. They’re gone now. BTW, organic does not mean without pesticides, it means without synthetic pesticides. Also, I believe that some frozen fruits & veggies “may” have less chemicals (at least on the surface) because they’re rinsed before freezing, but you can research that for yourself.


      RE: “baggman744” asks about cost and availability of nutritious, affordable berries–

      Even your own area may have a network of local berry and fruit orchard farms, and by contacting the respective farms, you can determine which you can trust to be free of hazardous chemicals. Once you find the farms which are within driving distance and offer affordable prices, you can stock your freezer each year by a furious campaign of berry picking. In the Southeast US, for example, the blueberry season lasts from late May through perhaps the first week or so of August.

      Find a Berry Farm or Fruit Orchard Near Your Home–

      But why go to all the trouble of picking, when you can buy the fruit juice, instead? As Dr. Greger points out, even grape juice extract has been demonstrated nutritionally effective (compared with its whole fruit) and Welch’s would persuade us its products are affordable, but the nutritional champion is still the whole fruit, kept year-round in the freezer. That “whole fruit and nothing but the fruit” is the charter and founding statement for a yearly consumer berry-gathering expedition– not to mention a powerful incentive for other farms to enter the berry harvest economy, driving down prices (in theory, at least) and perhaps using a better variety of berry.

      Juicing Removes More than Just the Fiber–

      Note cranberries and other berries have many similar benefits to blueberries, although Dr. Greger mentions only blueberries in the context of this article. Compared in certain respects with blueberries, even the lowly cranberry and lemon may be as effective, or even more effective at promotion of apoptosis and fighting angiogenesis / development of tumors.

      Which Fruit Fights Cancer Better?

      Cranberries vs. Cancer–

      Finally, you may be able to start your own berry patch in your backyard. For example, by buying a box of blackberry or marionberry fruit from the supermarket– but only USA-grown berries (see label)– you can put a few berries aside for seeds, and plant them at the right period in your growing zone for berry cultivation. You must start cautiously, taking into account the soil composition, temperature, sun exposure and nutrients required, but most factors are easily understood and relatively simple to manage.

      Ultimately, considering the investment of time and effort, you may decide to let professional farmers do the hard part, content only to harvest and put away quite a volume of berries each year. By doing even that much, you promote both your health and the local farm economy.

    1. I think most studies show like a half-cup to a cup of berries. So not much at all. Feel free to browse the “sources cited” section of this video to see the exact doses. If you can’t find it holler and I’ll look. Thanks, David.

      1. I don’t see a “sources cited” section. Do you mean the hyperlinked articles? I think the amount is critical and a definitive answer with sources would be great.

        1. Ok no problem. I know there are many buttons on the site. I was referring to the video “How to Slow Brain Aging by Two Years” that I hyperlinked in my comment above. You are right that this blog post only has hyperlinks and they do link to the studies themselves, but if you get to the video, under the title there are buttons that are super helpful like “View Transcripts” and “Sources Cited” which show all of the research papers used to create the video.

          The amount of berries consumed differ from each study. For example, the Concord grape study gave about 15ounces of grape juice daily, but those with more body weight drank a bit more. In the Harvard Nurses’ Health Study women eating more more than 1 serving of blueberries per week and more than 2 servings of strawberries (a half cup is a serving) per week had better results. So I’d say a half-cup to a cup of berries per day is all you’d need to see improvements, which is pretty constant with other studies the Dr. Greger covers in the video How Much Fruit is Too Much? I also think variety is key, as berries are high in anthocyanidins other foods like oranges and tea have far more flavones and flavonols.

    2. Here is an exerpt from Life Extension Magazine which did a cover story on blueberries in the April 2015 issue: “Why not just eat the berries and get the anthocyanins from your diet? For one thing, it would be prohibitively expensive, since whole-berry studies typically require 350 grams (about 3/4 of a pound) of berries to achieve effects…eating too many whole blueberries can offset the incredible benefits conferred by the natural polyphenols they contain. The cost of blueberry extract is also quite low in comparison to the whole fruit.” They go on to state, “Blueberry extract (including stems) is even more potent the the whole berry or juice, providing greater metabolic support throughout the entire body and without the excess sugar of the raw fruit….wild blueberries possess up to 10 times the nutritional capacity of cultivated berries.”

      1. Full article for those interested:

        I take one supplement from LEF. They have a good reputation for integrity, safety, and seem to reference a lot of credible research. But you have to remember, they’re in the business of selling supplements. IMHO: unless I have very good specific reason to take a concentrated processed food supplement, I’d rather just eat the food. So far, the only supplement I know of that Dr. Greger recommends for strict vegans (of which I am not), is B12. If you don’t eat blueberries, start. If you do, then do you “need” added blueberry extract in a pill? To each his own on that one. I’m a big fan of “JERF”: Just Eat Real Food.

  4. Just an hour ago I came upon some unopened bags of aronia berries (black chokeberries) stored in the back of the freezer, and forgotten — “until now” (LOL). A quick nutrition profile search mentions their huge anthocyanidin content, the highest of any berry in fact. Many other antioxidants as well.

    Then tasting them reminded me why they got tossed: they taste like cardboard!

    But now mixing them with wild blueberries and pomegranate juice and lightly sprinkling with stevia powder makes all the sweet difference.

    1. @Dommy–
      How did the berries taste before you decided to freeze them? Their taste must have been incentive enough.

      In any case, frozen fruit is not the perfect substitute for fresh fruit, but frozen is what most of us must live with most of the year. Because we cannot depend on grocers for a continuous supply of fresh, USA-produced fruit, we must rely on the “time machine” of the home freezer for our supply.

      More to the point, most of us do not live where we have the luxury of nibbling fresh berries from a nearby farm over the several months of a growing season– we must go to the producers / orchards and berry farms, themselves, and freeze what we harvest. At prevailing cost-per-pound, we spend about half as much by harvesting on our own.

  5. Dr. Greger clearly prefers whole foods or perhaps juices in the case of concord grapes, to supplements containing single phytonutrients. But what about blueberry or pomegranate concentrate pills I’ve seen for sale on the internet and heath magazines? Or what about elderberry syrup or grapeseed or hawthorn extract capsules etc.? Is there any benefit from taking them or are they a waste of money?

    1. I wouldn’t go for the pills, but elderberry and hawthorn if used in the right circumstances I believe would have value.

  6. Are dried fruits like raisins and dried wild blueberries as nutritious in polyphenols and anthocyanidins as fresh whole grapes or blueberries? (Dried or baked kale chips–as nutritious as non-dried kale?) Thanks

    1. Yes, I think dried fruit has it’s place. it still has many of the polyphenol properties. When fresh is not available I see no concern with dried or frozen fruit and however you’re going to eat more kale is fine with me :-)

  7. Question for the dietitian:

    Blueberries are so tasty that they are easy to add, but I read recently that beet juice had been shown in a study to lower blood pressure significantly. My question is whether whole beets steamed are as effective as beet juice? Also, should I limit the amount of beets I eat because of the sugar in them? I have been eating 3/4 cup of steamed beets a day to lower blood pressure. See article:

    Hypertension. 2015 Feb;65(2):320-7. doi: 10.1161/HYPERTENSIONAHA.114.04675. Epub 2014 Nov 24.

    Dietary nitrate provides sustained blood pressure lowering in hypertensive patients: a randomized, phase 2, double-blind, placebo-controlled study.

    Kapil V1, Khambata RS1, Robertson A1, Caulfield MJ1, Ahluwalia A2.

    1. I think steamed beets are delicious and beneficial. Often studies are conducted for ease so they may have used beet juice because participants handle better than eating whole steamed beets (I am not certain if this is the case here). I suggest eating beets and blueberries! Rule of thumb – foods in their whole state are preferred. Keep up the healthful eating!

  8. My word recall has significantly improved in recent weeks (62, female). Noticeable to spouse. I’ve made a number of improvements in diet this year, but improvement in word recall SEEMS to be correlated with inclusion of 1/2 c or so of frozen blueberries/strawberries/cherries in daily smoothie. Before, I would need a word like “anthrax”, say, and would have difficulty pulling it immediately from the “a” shelf, rather than a similar word. (My brain seems to store words alphabetically? :-) Small sample size (1!), many confounding factors, but reason enough for me to continue with the berries!

  9. You wrote, ““long-term consumption of berries was related to significantly slower rates of cognitive decline. . . ” I wish popular writers would state whether they mean “statistically significant” or “wow, that was really significant!” I’m a scientist and am familiar with the difference. But a statistically significant difference might be trivial, just that there was 95% chance that the observed difference was not by chance. Using the same word for quite different meanings, either of which might be the one meant, leads everyone including scientists to be confused.

    1. Thanks for the suggestion. Note that the link to the Harvard Nurse’s Health Study is provided and anyone can dig into the papers themselves for more clarification.

  10. I don’t know where to write this question, so I’m posting it here, because it’s about berries’ properties. This question is for Dr. Greger and his team.

    In your opinion, what is the reason why, in some studies, whole berrries don’t have the beneficial effect of extracted and purified berries’ antioxidants?

    I’d like, in particular, a comment on this interesting study:

    Thank you so much for your possible explanation.

  11. I just watched one of your hour long vids from ~2002 where you reviewed data on diet vs various diseases. Vegetarians and vegans fared no better than meat eaters except for with neurological diseases where non-meat eaters fared worse! Have those studies been updated to examine the causes? You postulated low omega-3’s and B12 levels as contributors to disease but I don’t know if that was actually tested. thx

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