American Diet Negatively Impacts Learning and Memory
Dr. Kathie F. Nunley
increased their daily consumption of calories by more than 25% over
the past 50 years. We are now beginning to see the deleterious effect
this diet change is having on our brains, particularly in how it
impacts learning and memory.
consumption and its associated weight gain has been linked to many
health related problems such as high blood pressure, insulin levels
and measures of inflammation. But we are now seeing a wide range
of research projects linking these high insulin levels and inflammation
to cognitive problems, both in young children trying to learn and
aging adults and the rise in Alzheimer's.
area of concern for educators is the effect these diets have on
the hippocampus - the brain region in charge of memory formation
- the cornerstone to learning. The vast majority of the increased
calories consumed is coming from saturated fats and refined carbohydrates.
Diets high in fats and refined sugars cause significant impairment
to the hippocampus. These diets slow neurogenesis, the hippocampus'
ability to regrow and replenish new neurons; they also have a negative
effect on synaptic plasticity and they lead to a decrease in chemicals
responsible for neuron growth.
associated with our American diet is how it undermines emotional-enhanced
learning. Normally, a moderate amount of stress or emotional excitement
leads to an increase in learning and retention. But diets high in
sugar and high fructose corn syrup, cause a decrease in stress-induced
corticosterone release. That means, they negate the effect. So while
we would expect highly motivated, excited children, under a moderate
amount of stress, to learn faster and perform better on tests, we
may have lost that advantage due to our high
much of this research has been done using rats in a laboratory,
we are also seeing new reserach using humans in the real world.
And this research also points to the problems associated with high
sugar diets that are also low in Omega-3 fatty acids (another hallmark
of the Standard American Diet).
piece of research, out of UCLA, showed that students with high
sugar intake and the common high Omega 6 / low Omega 3 diet, had
lower cognitive scores and insulin resistance. The good news in
this reserach is that Interestingly, once diets were supplemented
with high Omega-3 foods, many of the the negative cognitive effects
of the high sugar diets were eliminated.
A separate research
project looked at the diets of children aged 7 - 9. They compared
groups of children who had diets high in saturated fatty acids (Omega-6)
with those whose diets were higher in Omega-3 fatty acids. Those
children high in Omega 6's had
much lower memory and learning scores than did children whose diets
include high Omega-3 fatty acids. The children who had high Omega-3
diets just had better hippocampal function.
So what are
educators and parents to do? Education in our schools should include
information on how children learn best and that includes nutrition.
Schools need to be an example of how to create healthier climates
for learning. These could include:
High Fructose Corn Syrup and high Omega-6 oils from the cafeteria
and vending. (read labels, avoid vegetable oil, corn oil and "hydrogenated"
of Omega-3 rich foods: These include fish, flax, olive oil, coconut,
coconut oil, avacado, olives, palm oil, and fats from animals fed
in the difference between Healthy Fats and Unhealthy Fats.
food convenient. (Apples should always be presented sliced and ready
for dipping if we want them to compete with french fries!) Move
healthier options to the front and discount their price. Make unhealthy
food more expensive and harder to find.
caloric intake by providing higher protein options which eliminate
snacking and hunger throughout the day.
parents and students on the advantages of lower caloric diets, high
in Omega-3 fatty acids, low in Omega-6 foods and eliminating high
fructose corn syrup completely from the diet.
& Gomez-Pinilla F (2012). "Metabolic syndrom in the brain:
deficiency in omega-3 fatty acid exacerbates dysfunctions in insulin
receptor signalling and cognition." Journal of Physiology 590,
et al (2014). "Dietary Lipids are differentially associated
with hippocampal-dependent relational memory in prepubescent children."
American Journal of Clinical Nutrition. Vol 99(5); 1026-1032.
M. & Doraiswarmy, M. 2009. "Does Eating Fewer Calories
Improve the Brain?". Scientific American. March.
& Zied, E. (2010). The standard American diet and its relationship
to the health status of Americans. Nutrition in Clinical Practice,
Darling, J; & Parent, M. (2013). "High Energy Diets Prevent
the Enhancing Effects of Emotional Arousal on Memory." Behavioral
Neuroscience, Vol 127(5), 771-779.
Dr Kathie Nunley is an educational psychologist, researcher and
author of several books on parenting and teaching, including A
Student's Brain (Brains.org) and the best selling, "Differentiating
the High School Classroom" (Corwin Press). She is the developer
of the Layered Curriculum® method of instruction and has worked
with parents and educators around the world to better structure
schools to make brain-friendly environments. In addition, her
work has been used by the Boeing Corporation, Family Circle Magazine,
the Washington Post, and ABC television.
her: Kathie (at) brains.org