Doubts regarding research suggesting that “A Very Sugary Diet Makes You Stupid”

Read the article(s):
http://www.medicalnewstoday.com/articles/245531.php
http://newsroom.ucla.edu/portal/ucla/this-is-your-brain-on-sugar-ucla-233992.aspx

I have some doubts about the conclusions reached in this research.

“As a control, the animals were fed on standard rat feed for five days before the fructose diet started. They were also trained on a maze twice per day and tested to see how well they performed. They also placed visual markers in the maze to help the rats remember their way around.”

 Gomez-Pinilla recounts his experience of testing the rats after six weeks on the sugary diet:

    “The second group of rats navigated the maze much faster than the rats that did not receive omega-3 fatty acids … The DHA-deprived animals were slower, and their brains showed a decline in synaptic activity. Their brain cells had trouble signaling each other, disrupting the rats’ ability to think clearly and recall the route they’d learned six weeks earlier.”

Maybe, rather than omega-3 fatty acids negating a negative effect of fructose on synaptic activity, omega-3 combined with fructose may have enhanced activity and protected from damage to the synapses, leading to the rats’ increased performance in the maze tests.

“Our findings suggest that consuming DHA regularly protects the brain against fructose’s harmful effects …”

The researchers appear to have arrived at the conclusion that fructose (in abundance?) may have negative effects on cognitive activity and memory. I don’t believe that the results of this experiment necessarily point to this conclusion.

Both groups of rats were fed fructose, with the second group also being fed omega-3 fatty acids in the form of flaxseed oil and docosahexaenoic acid (DHA)
There should have been a further control group which was not fed fructose at all, to compare the other two groups against. This would determine whether fructose had any effect on the rat’s brain and performance in the maze tests, prior to investigating any effect that omega-3 fatty acids may have in “negating” this effect. Instead, the researchers gave fructose solutions to both groups of rats.

The UCLA article also suggests that the first group of rats, who did not receive omega-3 fatty acids, may have developed a resistance to insulin:  

"The DHA-deprived rats also developed signs of resistance to insulin, a hormone that controls blood sugar and regulates synaptic function in the brain. A closer look at the rats’ brain tissue suggested that insulin had lost much of its power to influence the brain cells."

"He suspects that fructose is the culprit behind the DHA-deficient rats’ brain dysfunction. Eating too much fructose could block insulin’s ability to regulate how cells use and store sugar for the energy required for processing thoughts and emotions."

I believe that this is the more appropriate route for the experiment to proceed. However, it is unclear whether it is fructose itself that is responsible for the DHA-deprived rat’s lower performance, or an interaction between insulin and fructose in the absence of omega-3 fatty acids.

More research should be done to determine an effect of fructose on the rats’ brain and performance, compared against a baseline, control group of rats who are not fed fructose solutions.

Nonetheless, it is known that omega-3 fatty acids protect the brain and enhance cognitive function and memory. However, it is not correct to conclude from this article that fructose has any negative effect on the brain.

Lead Interferes With The Synthesis And Function Of Brain-Derived Neurotropic Factor, Derailing The Brain's Center For Learning

Exposure to lead wreaks havoc in the brain, with consequences that include lower IQ and reduced potential for learning. But the precise mechanism by which lead alters nerve cells in the brain has largely remained unknown. 


New research led by Tomás R. Guilarte, PhD, Leon Hess Professor and Chair of Environmental Health Sciences at Columbia University Mailman School of Public Health, and post-doctoral research scientist Kirstie H. Stansfield, PhD, used high-powered fluorescent microscopy and other advanced techniques to painstakingly chart the varied ways lead inflicts its damage. They focused on signaling pathways involved in the production of brain-derived neurotropic factor, or BDNF, a chemical critical to the creation of new synapses in the hippocampus, the brain's center for memory and learning. 

The study appears online in the journal Toxicological Sciences. 

Once BDNF is produced in the nucleus, explains Dr. Stansfield, it is transported as cargo in a railroad-car-like vesicle along a track called a microtubule toward sites of release in the axon and dendritic spines. Vesicle navigation is controlled in part through activation (phosphorylation) of the huntingtin protein, which as its name suggests, was first identified through research into Huntington's disease. By looking at huntingtin expression, the researchers found that lead exposure, even in small amounts, is likely to impede or reverse the train by altering phosphorylation at a specific amino acid. 

The BDNF vesicle transport slowdown is just one of a variety of ways that lead impedes BDNF's function. The researchers also explored how lead curbs production of BDNF in the cell nucleus. One factor, they say, may be a protein called methyl CpG binding protein 2, or MeCP2, which has been linked with RETT syndrome and autism spectrum disorders and acts to "silence" BDNF gene transcription. 

The paper provides the first comprehensive working model of the ways by which lead exposure impairs synapse development and function. "Lead attacks the most fundamental aspect of the brain - the synapse. But by better understanding the numerous and complex ways this happens we will be better able to develop therapies that ameliorate the damage," says Dr. Guilarte. 

Columbia University's Mailman School of Public Hea. (2012, March 2). "Lead Interferes With The Synthesis And Function Of Brain-Derived Neurotropic Factor, Derailing The Brain's Center For Learning." Medical News Today.

Another reason to love music

Neuroscience of Music – How Music Enhances Learning Through Neuroplasticity

Neuroscience research into the neuroscience of music shows that musicians’ brains may be primed to distinguish meaningful sensory information from noise. This ability seems to enhance other cognitive abilities such as learning, language, memory and neuroplasticity of various brain areas.

The research strongly suggests that the neural connections made during musical training also prime the brain for other aspects of human communication.

An active engagement with musical sounds not only enhances neuroplasticity, she said, but also enables the nervous system to provide the stable scaffolding of meaningful patterns so important to learning.

“The brain is unable to process all of the available sensory information from second to second, and thus must selectively enhance what is relevant,” Kraus said. 

The Nature article reviews literature showing, for example, that musicians are more successful than non-musicians in learning to incorporate sound patterns for a new language into words. Children who are musically trained show stronger neural activation to pitch changes in speech and have a better vocabulary and reading ability than children who did not receive music training.

And musicians trained to hear sounds embedded in a rich network of melodies and harmonies are primed to understand speech in a noisy background. They exhibit both enhanced cognitive and sensory abilities that give them a distinct advantage for processing speech in challenging listening environments compared with non-musicians.

“The effect of music training suggests that, akin to physical exercise and its impact on body fitness, music is a resource that tones the brain for auditory fitness and thus requires society to re-examine the role of music in shaping individual development, ” the researchers conclude.

“Music training for the development of auditory skills,” by Nina Kraus and Bharath Chandrasekaran, will be published July 20 in the journal Nature Reviews Neuroscience.

Kraus, N., Chandrasekaran, B. (August 2010). Music training for the development of auditory skills. Nature Reviews Neuroscience, 11, 599-605.