A new study shows that a saturated fat diet is enough to cause memory problems and brain inflammation associated with older people.
The researchers provided separate groups of mice for a three-day or three-month high-fat diet to compare the rate of changes in the brain when eating an unhealthy diet with the rest of the body.
As expected by the Institute for Diabetes and Obesity based on previous Diabetes and Obesity, three-month fat foods caused metabolic problems, intestinal inflammation and rapid metastasis, while only three days of high fat fat without causing high fat.
However, when it comes to brain changes, the researchers found that only older rats (whether they lasted for three months or just three days on a high-fat diet) performed poorly on memory tests and showed negative inflammatory changes in the brain.
The results eliminate the idea of diet-related inflammation in the aging brain, said Ruth Barrientos, a researcher at the Ohio State University Institute of Behavioral Medicine. Most research on the effects of fat and processed foods on the brain has focused on obesity, but the effects of an unhealthy diet have nothing to do with obesity and have largely not been explored.
“Unhealthy diets are linked to obesity, but they are not inseparable. We are really looking for the effects of a straight diet on the brain. We show that within three days, before obesity begins, a huge neuroinflammatory transition occurs.
“The physical changes in all animals are happening slowly, and are not actually necessary to cause memory disorders and brain changes. We will never know that brain inflammation is the main cause of memory disorders caused by a high-fat diet without comparing the two schedules.”
The study was recently published in the Journal of Immunity and aging.
Years of research conducted in Barrientos labs over the years show that aging brings long-term “start” of inflammatory traits of the brain, coupled with loss of brain cell reserves to rebound, and an unhealthy diet can make the brain worse for older people.
Fat composition studies used 60% of the calories in high-fat diets, which may be equivalent to a range of common fast food choices: For example, nutritional data suggest that fat makes up 60% of the calories of cheese in McDonald’s double-smoked BLT quarter pound cheese, or burger king with cheese.
After the animals had a high-fat diet of three days or three months, the researchers conducted a test to evaluate two types of memory problems common to patients with Alzheimer’s disease based on different areas of the brain: contextual memory mediated by the hippocampus, the main memory center of the brain, and cue-toring memory originating from fear and brain centers in Amygdala.
Compared to control animals eating food on a high-fat diet and young rats, the elderly rats showed behavior that both memories were impaired after only three days of fat food – this behavior continued as they continued on a high-fat diet for three months.
The researchers also saw three days of fatty food, in the brains of elderly rats, a series of protein levels, called cytokines, suggesting a dysregulated inflammatory response. After three months of a high-fat diet, some cytokine levels changed but remained dysregulated and cognitive problems persisted in behavioral testing.
“Dialogue from baseline markers of inflammation is a negative reaction that has been shown to impair learning and memory function,” Barrientos said.
Young animals gained weight compared to rats who ate normal foods and showed signs of metabolic dysfunction – poor insulin and blood sugar control, inflammatory proteins in fat (fat) tissues, and altered gut microbiome – after three months of a high-fat diet. The memory and behavior and brain tissue of young rats remain unaffected by fat foods.
“These diets lead to obesity-related changes in young and older animals, but younger animals seem to be more resilient to the effects of high-fat diets on memory. We think this may be due to their ability to activate compensatory anti-inflammatory responses lacking in older animals,” Barrientos said.
“In addition, with inflammation in glucose, insulin and lipoflavorous, inflammation in young and older animals has increased, and if you only look at what is happening in your body, you can’t tell the difference between what’s causing memory dysfunction in older animals. For memory response, this is what’s happening in the brain.”
This work was granted by the National Institute of Aging.
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