My Boy's Wicked Smart: Eliminating High Sugar Diets to Boost Kids' Brain Function

With children and adolescents consuming an average of 85 grams of added sugar (not counting natural!) in their diet daily, the exact same amount as adults, I thought we could set aside a little time today to talk about a very special part of the brain called the hippocampus.

I will say at first, I honestly didn't think I read this data right. I did get it straight off of the CDC website, and it's their latest estimate (that I could find) from 2017-2018. I wonder, with all of the at-home time since the spring of 2020, whether sugar consumption among children may now be even more, well, dangerous. Reports have recently been emerging that Type 2 Diabetes in children may have doubled, even tripled, in some areas of the country due to lack of physical exercise and excessive eating while in social isolation.

The hippocampus, Latin for seahorse due to its shape, is embedded deep in the brain's temporal lobe and plays a crucial role in learning and memory. Published research articles have been linking the consumption of high amounts of sugar in adolescence with damage and atrophy to the hippocampus. This damage seen in younger people can manifest as deficits in attention, learning, and memory, and eventually externalize as the nightmare that is Alzheimer's disease. The hippocampus is the earliest and most severely affected structure in Alzheimer's disease.

A new study released in June 2021 called Long-Term Over-Consumption of Sugar Starting in Adolescence Produces Persistent Hyperactivity and Neuro-Cognitive Deficits in Adulthood estimated sugar consumption to be greater than 100 grams per day in children, adolescents and adults. The researchers found that long-term sugar consumption caused deficits in hippocampal-dependent learning and memory and altered hippocampal neurogenesis, with an overall decrease in the proliferation and differentiation of newborn neurons. They concluded that "long-term over-consumption of sugar, as that which occurs in the Western Diet, might contribute to an increased risk of developing persistent hyperactivity and neuro-cognitive deficits in adulthood."

Another 2021 study called Early Life Western Diet-Induced Memory Impairments and Gut Microbiome Changes in Female Rats are Long-Lasting Despite Healthy Dietary Intervention found a high sugar and fat diet impaired hippocampus-dependent memory, caused weight gain, and altered gut microbial population in adolescent female rats. While switching to a healthier diet led to reversal of the weight gain, the hippocampus-dependent memory impairments and the gut microbiome dysbiosis persisted throughout adulthood.

The 2019 study Early-Life Sugar Consumption has Long-Term Negative Effects on Memory Function in Male Rats determined "even modest sugar-sweetened beverage consumption throughout early life may have long-term negative consequences on memory function during adulthood." 

In the 2016 study Sugar Consumption Produces Effects Similar to Early Life Stress Exposure on Hippocampal Markers of Neurogenesis and Stress Response, researchers concluded that chronic sugar consumption in the early life of female rats had long-term reduced hippocampal expression very similar to what was seen in female rats exposed to adverse early life experience. If similar processes are at play in humans, this could demonstrate that children consuming high amounts of sugar in a stable, content environment may be undergoing similar brain development challenges that are seen in children in psychologically detrimental environments.

The 2002 study A High-Fat, Refined Sugar Diet Reduces Hippocampal Brain-Derived Neurotrophic Factor, Neuronal Plasticity, and Learning found that just two months on a high refined-sugar diet was sufficient to reduce hippocampal levels of brain-derived neurotrophic factor and spatial learning performance.

The 2015 study Effects of Sucrose and High Fructose Corn Syrup Consumption on Spacial Memory Function and Hippocampal Neuroinflammation in Adolescent Rats observed that rats consuming both sucrose and high fructose corn syrup had impaired spacial learning and memory, and concluded that "consumption of added sugars, particularly high fructose corn syrup, negatively impacts hippocampal function, metabolic outcomes, and neuroinflammation when consumed in excess during the adolescent period of development."

The 2016 paper Early Life Exposure to Obesogenic Diets and Learning and Memory Dysfunction noted that "the juvenile/adolescent period is a particularly vulnerable time for diet-induced impairments in hippocampal function, and recent evidence suggests that sugar can be as potent or more potent than high-fat diets in its deleterious effects on memory." The function of the hippocampus can become impaired from high sugar, high fat diets even in the absence of obesity or excess body fat, the study added.