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Wednesday, February 11, 2009

Eat Your Blueberries - But Not With Cereal.

I have reported earlier on a study indicating that blueberries are good for memory. Actually, there are several studies indicating that blueberries are good for mental function in general. Blueberries contain polyphenolics, the levels of which are indicated by the amount of two compounds, ferulic acid and caffeic acid. Ferulic acid helps to stabilize cell walls and protects the nervous system. It lowers blood pressure. Caffeic acid also protects neurons and may even prevent neural degeneration. Both compounds are powerful antioxidants.

Blueberries are potent anti-inflammatory agents. One study in rats fed a diet including a non-steroidal anti-inflammatory drug or a 2% blueberry diet showed that within just two weeks the blueberry supplement activated anti-inflammatory genes in the brain much more than did the anti-inflammatory drug.

Now, a recent report indicates that the health benefits of blueberries are blocked by milk. Phenolics have a high affinity for protein, and the binding to milk protein prevents phenolics from accessing body cells. The study that demonstrated this effect involved measuring blood levels of the blueberry phenolics at various times after human volunteers consumed 200 gms of blueberries with 200 ml of either water or milk. Levels of phenolics rose sharply when water was consumed, but there was no increase when milk was consumed.

Heat destroys blueberry phenolics. So even though blueberry pie tastes great, it won't help your health. Only fresh blueberries provide useful levels of phenolics.

So, the recommendation is to consume blueberries without proteins. It should suffice to eat blueberries either one hour before eating other foods or two hours afterwards. For me, I will eat my blueberries alone an hour before my milk and cereal.


Serafini, M. et al. 2009. Antioxidant activity of blueberry fruit is impaired by association with milk. Free Radical Biology and Medicine. doi:10.1016/j.freeradbiomed.2008.11.023

Shukitt-Hale, B. et al. 2008. Blueberry polyphenols attenuate kainic acid-induced decrements in cognition and alter inflammatory gene expression in rat hippocampus. Nutr. Neuroscience. 11 (4): 172-182.


  1. Hello, Dr. Bill! I just discovered your blog which I am very impressed with and was extra thrilled to discover you are an Aggie - WHOOP! I have a question about blueberries. I have recently been eating a mixture of blueberries, plain yogurt and Fiber One Cereal and was pretty darn proud of myself for coming up with something so healthy. Although you have targeted milk as being a no-no when mixed with blueberries, would the same apply to yogurt because it also contains protein? Please confirm - thank you so much! Jane/Proud Aggie Mom

  2. RE: blueberries and protein


    I suspect all proteins will have a similar tendency to tie up the active ingredients of blueberries. The only study of this issue I know of is the one on milk proteins that I posted.

    In the meanwhile, I decided to eat blueberries alone, about an hour before I have breakfast.

  3. bradyray4:27 PM

    Hi Dr. Bill. I recently complained to my doctor about my 82 year old memory. She suggested blueberries. I have been eating 5 ounces per day in my morning milkshake of banana, yogurt, oatmeal, one cup Slimfast and 2% milk. I will eat blueberries one hour before. How many ounces should I eat? Thanks, Brady

  4. TammyB4:11 PM

    So....can you eat too many blueberries? I have just recently fallen in love with them, and eat one cup per day - if I increase that, will the benefits increase as well?

  5. In response to Brady Ray, I don't know how many blueberries are necessary to have a memory effect. This relates to my answer to Tammy B, which is I don't think anybody has done a dose-response analysis to find out what amount of blueberries produces the maximum benefit. I have no information on what amount of blueberries is too much, but my hu8nch is that they are pretty safe.

  6. Anonymous4:51 PM

    I recently read that blueberries help to burn belly fat. You're supposed to have 1 1/2 cups a day. Any truth to that? Thank you.

  7. Re: burning belly fat

    I know of no scientific evidence that anything selectively burns belly fat. If you want to burn belly fat, you have to burn fat in general, and that is done by eating fewer calories and exercising more. There are no magic potions.

  8. What about the binding factor regarding soymilk and blueberries? You said "milk proteins" at first and then later said "proteins". Which is it?

    Thanks for your is very interesting!

  9. Anonymous7:27 PM

    Would freezing the blueberries reduce the amount of phenolics in the blueberries? What does freezing do to the entire nutrition content of the blueberries?

  10. Anonymous7:52 AM


    would the pill with extract do the same effect?

  11. I think it should. But the caveat mentioned earlier about proteins in milk and other foods might prevent absorption of the key ingredient.
    Can one get concentrated blueberry extract? If so, where? If so, how can we be sure that the beneficial components are not destroyed in extraction and processing?

  12. Suzanne Leaphart3:47 PM

    I am wondering if you feel there is a significant benefit to using organically grown blueberries versus the conventional (and cheaper by far) pesticide-infused ones.
    This information is being forwarded to my 85 year old mother who was just "put" on Arisept for memory failure. Intellectually she is intact, physically she is an amazing athlete; but short term activities of daily living memory is really getting rough. As a nurse clinician I have serious doubt about use of Arisept.

  13. To answer Suzanne about organic vs. conventionally grown berries:

    I don't think it would make any difference. As for Aricept, it can have bad side effects, but theoretically it could help. It augments the function of acetylcholine neurotransmission, which is prominent in the neocortex.

    Bill Klemm

  14. Anonymous10:44 PM

    Can I eat enough blueberries to make Lipitor consumption unnecessary for cholesterol control?

  15. Good evening Dr. Bill,

    My family (and I) are concerned about the amount of blueberries I have recently been eating per day. Some days i have been consuming upward of 24 ounces.

    I eat then frozen and can't resist the way they taste and feel in my mouth.

    I am concerned that there may be something harmful in easting ALL these delicious little frozen guys!

    What are you thoughts and or any study you know of?

  16. I'm wondering if any fruits or vegetables at all should be eaten with any meal containing any sources of protein, including that from grain. Perhaps that old recommendation of combining foods from the entire "food pyramid" at each meal is counterproductive. Are the nutrients from my peas and carrots doing me any good when I eat them with a piece of grilled chicken, I wonder?

  17. Thanks for this post. It's nearly two years old now, so just wondering if there's been any further studies to backup the theory?

  18. No, not that I know of.

    Memory Medic

  19. I have a really shoddy memory, not at all due to lack of listening skills, and I am only eighteen. It frustrates people around me quite often, which really upsets me, because it is not at all intentional. People see it as disrespectful (understandably so) quite often, but I'm not trying to be. I try to be as respectful of the people around me as I possibly can. But more often than not my memory makes that an impossibility. I was wondering if:
    1) there are any other foods that contain the same polyphenolics as blueberries, because the dining hall on campus does not ever serve blueberries, and I am a broke college student, so I can't pay for them myself, but I really really need to solve, or at least greatly improve, my memory problems.
    2) When I am able to attain some blueberries (when I go home), is it alright if I eat them frozen? Will they still help improve my memory? Because I am honestly not a big fan of blueberries at all, but if it will help my memory, then I am 10,000% willing to suck it up and eat them. However, I was thinking that maybe eating them frozen would maybe help in making them a bit more appetizing to me. Do you have any idea if that would detract or completely eliminate the memory improving abilities of the polyphenolics? If it does, then again, I will be able to suck it up, especially if blueberries are the only food with these polyphenolics in them, but if it doesn't detract/eliminate their memory improvement capabilities, then that would be wonderful.
    I know this post is ten days away from being three years old, but a response to my questions as soon as you are able to would be so greatly appreciated. I am in college. Poor memory is now more than ever a SERIOUS debilitating quality that I just cannot live with anymore. I need a solution. Again, please get back to me as soon as you get this/know the answers. I will appreciate it more than you could ever possibly know. Thank you so much.

    1. I am sorry about the delayed response. For whatever reason, I just now found it.

      1. I would not thinking freezing matters.
      2. Resveratrol is a good anti-oxidant (its in blueberries, too) and you can buy concentrated capsules (my local Sam's Club carries it).
      3. Your problems, at your age, need other approaches. Unless you have a really crummy diet, what you eat is a minor factor.
      4. Have you read my e-book, Better Grades. Less Effort. See

  20. The berries keep getting better. A U.S. Department of Agriculture scientist has found in them a compound that appears to be effective in lowering the bad forms of cholesterol. Of all the blueberries health benefits, perhaps the most famous is resveratrol. While few know that blueberries are a source of resveratrol, many know the health benefits from the stories and news on red wine. Resveratrol in blueberries helps combat the signs of aging, improve life extension, fight disease, prevent free radical damage and increase cardiovascular function.

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