It is hard to imagine that sugar was virtually unknown a few hundred years ago. The past four decades have witnessed an increase in sugar consumption of 127% per capita, despite the fact that the World Health Organization (WHO) recommends a total dietary intake of no more than five teaspoons per day.
As a society, we have become addicted to sugar; it is embedded into our diets from an early age. Even during pregnancy, when mothers are incorrectly encouraged to eat for two, “pregnancy cravings” are often for sugar-laden snacks. Due to hidden sugar in various foodstuffs, young children are often inadvertently victims of high sugar consumption.
While the mechanisms and consequences of sugar overconsumption on physical health in humans – especially in adolescents – are well described, less is known about its effect on cognition, behaviour and mental health.
Many studies have shown that the intrauterine environment plays a defining role in the programming of permanent postnatal physiology and pathophysiology, thus predisposing progeny to adulthood illness.
What a rodent study revealed
Dr Rochelle van Wijk from the Division of Clinical Anatomy in the Faculty of Medicine and Health Sciences at SU recently completed her PhD study in which she determined the detrimental effects that a high-sugar diet during gestation period and in the early life of rat offspring has on memory and brain structure.
More specifically, her study investigated the effects of a high-sucrose diet on cognitive function and brain histomorphology (the study of brain tissues’ cellular structure and formation) in albino Wistar rats by means of feeding high-sugar diets to pregnant dams and also to offspring once weaned. The results suggest that environmental conditions both before and after birth may have persistent effects on the health of offspring, predisposing them to cognitive decline.
It was also found that proper early nutrition is especially critical for long-term, stable cognitive function. The consumption of high levels of sucrose before birth, as well as during early development and “adolescence”, impaired hippocampal-dependent spatial memory in male and female rats with accompanied histological changes.
Both memory and histological changes occurred soon after exposure to high-sucrose feed. These changes manifested in the absence of overt metabolic dysregulation. Furthermore, the memory and histological changes occurred to a lesser degree in first-generation animals that were switched to a diet devoid of sugar after birth, suggesting that the changes described can occur independently of maternal feed.
It was concluded that, relative to control animals on a matched control diet using corn starch, rats with unrestricted access to a solid diet of 68% sucrose for a seven-week post-weaning period, displayed impaired spatial memory in the Morris water maze task. This task is widely used in behavioral neuroscience research to study the psychological processes and neural mechanisms of spatial learning and memory.
The findings of this rodent study highlight that high sugar intake in early life may have lasting effects on brain structure. Even though the study was conducted on rats, it is suggested that similar exposure to sucrose in humans may cause the same changes in children, thereby potentially increasing their didactic needs in the future. These findings are important for diabetes and metabolic syndrome management during pregnancy and early childhood.