A high-fat diet not unlike the average western one made young mice display ADHD-like behavior.
A recent study conducted at the University of Illinois and lead by Dr. Gregory Freund, a member of the university’s Division of Nutritional Sciences, found a significant link between high-fat diets and memory-dependent learning impairments like attention deficit hyperactivity disorder (ADHD).
We found that a high-fat diet rapidly affected dopamine metabolism in the brains of juvenile mice, triggering anxious behaviors and learning deficiencies. Interestingly, when methylphenidate (otherwise known as Ritalin) was administered, the learning and memory problems went away, said Dr. Freund.
The study was published in the journal Psychoneuroendocrinology.
Interestingly, Freund noted that both the brain of an ADHD person and the brain of an obese person shared a similar alteration in their dopamine signalling and asserts that an increase in the amount of dopamine metabolites is correlated with anxiety-like behaviors in children.
The study itself was sparked by the observation of rising rates of cognitive impairments such as ADHD as well as childhood obesity. To examine if there was a relationship. Dr. Freund and his team compared high-fat and low-fat diets (where fat comprised 60% an 10% of the diets respectively) in two separate groups of four-week old mice. For perspective, the average American diet consists of between 35 and 45% fat.
After only one week of the high-fat diet, even before we were able to see any weight gain, the behavior of the mice in the first group (high-fat) began to change, Dr. Freund said.
Symptoms of anxiety were evidenced including increased burrowing and the use of their wheel, as well as a contempt for exploring open spaces. Memory and learning deficits were also apparent, with decrease ability to navigate a maze and diminished object recognizing abilities.
Behavior Normalized after High-Fat Diet Ceased
Returning some of the high-fat group of mice to a low-fat diet saw cognitive abilities return to normal within one week. Those who remained on the diet retained the symptoms for approximately 10 weeks, after which the body was able to compensate for the diet mentally, but had become obese and developed diabetes. This result has also confirmed previous findings on the subject.
Although the mice grow out of these anxious behaviors and learning deficiencies, the study suggests to me that a high-fat diet could trigger anxiety and memory disorders in a child who is genetically or environmentally susceptible to them, Freund said.
The scientists hypothesized that removing the fat from the diet abruptly, or going ‘cold turkey,’ would negatively affect these cognitive impairments and stimulate increased anxiety and decreased ability to learn.
This hypothesis was validated when the researchers saw evidence that the high fat diet created chemical responses similar to ones that are witnessed in addiction cases.