While "you are what you eat" is considered a cliche these days, the impact of taking in too many saturated fats, simple sugars, and cholesterol can't be underestimated. Obesity has become an epidemic in most developed countries with horrendous economic costs in terms of greater need for health care, shortened lives, and lost work hours. Recent research has found a strong link between high fat, high sugar "Western diets" (WD for short) and various neurodegenerative conditions such as Parkinson's disease, dementia, and various kinds of cognitive functioning.
To examine which areas of the brain are most vulnerable WD exposure, animal research has been especially valuable. Research studies comparing the rats with diet-induced obesity (DIO) to their leaner counterparts in terms of brain functioning has implicated the hippocampus in particular as being especially impaired.
The hippocampus is part of the brain's limbic system and is especially important in memory functioning and spatial navigation. In Alzheimer's disease and other kinds of dementia, the hippocampus is one of the first areas of the brain to be affected leading to patients becoming unable to form new memories. Cognitive testing in rats has shown that damage to the hippocampus can lead to increased weight gain since rats begin eating indiscriminately, even when not hungry. Even in rats without obesity, greater exposure to high-fat, high-sugar diets develop cognitive impairments linked to the hippocampus which then leads to weight gain.
But why does exposure to a Western diet affect the hippocampus in particular?
To read more, check put my new Psychology Today blog post.