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A new study shows that sugar may not be so sweet for the brain – and may lead to memory problems.

Researchers from four universities report in the Annals of Neurology that people who absorb glucose more slowly than those who metabolize it quickly are more forgetful and are more likely to have a faulty dentate gyrus, a pocket in the hippocampus section of the brain. The hippocampus is involved with learning and memory formation. 

The findings were based on glucose testing, memory evaluations and fMRI scans of the brains of 240 healthy people ages 65 and older without dementia, and applied even in those without diabetes, which is characterized by an inability to readily convert sugar into energy.

Glucose metabolism naturally slows with age, and memory begins to decline in our 30s, says co-author Scott Small, an associate professor of neurology at Columbia University Medical Center in New York. The new study suggests a possible association between the two, because elevated blood sugar appears to damage the dentate gyrus, Small says.

The dentate gyrus's exact function is unknown. But it's one of several circuits in the hippocampus that, if disrupted, impairs memory, such as a person's ability to learn the names of new people or to remember where they parked their car.

The possible connection between its dysfunction and poor glucose regulation may explain earlier observations that exercise benefits the dentate gyrus, Small says. Until now, scientists believed that physical activity reduced the risk of age-related memory loss by allowing glucose to be absorbed more quickly into muscle cells, but were not sure why. This indicates, Small says, that the dentate gyrus could be the missing link.

8 Comments

1. 1. virtuPIC 08:06 AM 12/31/08

   Umm... interesting. There also was a PET study at Irvine, CA that there is a '...statistically significant negative correlations between glucose use and task performance...' and that playing Tetris slows down glucose metabolism. Details and links here: http://www.airspace-v.com/ggadgets

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2. 2. L.W. Lucas, MD 07:30 PM 12/31/08

   This brief summary is poorly written to the point where its meaning is not clear. I am guessing that the "...people who absorb glucose more slowly than those who metabolize it quickly..." line can be explicated as follows:
   Inactive people who utilize glucose poorly and therefore maintain a higher blood and brain glucose level remember less well, presumably due to the impact of higher glucose levels on the dentate gyrus of the hippocampus. Exercise increases the absorption of glucose into muscles, therefore leading to lower blood and brain glucose levels and a relative sparing of memory function in the long run for those who engage in regular exercise. Did I read between the lines correctly? Luke

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3. 3. Typhoonguywlblwu 07:53 AM 1/1/09

   I completely agree luke as excercing would require more glucose and hence its the level of glucose present and not the glucose absorbed which would have an impact on the dentate gyrus. :0)
   
   Anks MBA aspirant.

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4. 4. pradhangeorge 01:05 PM 1/2/09

   Certainly interesting. but a field medical doctor like me is not impressed. The human digestive is planned for dealing with raw material, the starches for the glucose and so on. day to day work activity to grow and gather find food and protect the family is enuf work for the body muscle nerve and brain. we need not at all talk of intricate metabolic processes except for research and learning. shd such articles as these be sent to the deep research magazines? and not in general scientific American???

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5. 5. Sgreene523 10:53 PM 1/2/09

   This article is pretty much saying that sugar makes the memory bad and yet again exercise is the answer. Exercise has been proven to benfit almost everythign to do with our body and mind so it does not suprise me that our memory is affected by it aswell. The article does not get into exactly what the title implies and would have been better given there was a deeper explantion of how the glucose was absorbed into the muscles ect. But that may just be me. Furhermore, i was not suprised by this and felt the article to be almost predictable.

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6. 6. grigory in reply to Typhoonguywlblwu 11:18 AM 1/28/09

   Especially, exercising outside and not inside a gym or one's house. Fresh air is very important part of it.

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7. 7. trevormemory 09:15 PM 2/3/09

   What about the whole affect of carbs? See http://worldfitnessnetwork.com/2009/01/low-carb-diets-blur-memory/ .

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8. 8. jamesperterson 01:21 AM 2/27/09

   Very interesting Post!!!.
   
   http://allnutri.com/pid1946/citicoline.aspx
   

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