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.
Sources:
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.
11 comments:
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
RE: blueberries and protein
Jane:
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.
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
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?
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.
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.
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.
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 blog...it is very interesting!
Would freezing the blueberries reduce the amount of phenolics in the blueberries? What does freezing do to the entire nutrition content of the blueberries?
Hello,
would the pill with extract do the same effect?
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?
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