When fed a fasting-mimicking diet, mice genetically engineered to develop Alzheimer's display fewer signs of the condition. The corresponding research was conducted by researchers at the University of Southern California Leonard Davis School of Gerontology and published in Cell Reports.
The fasting-mimicking diet (FMD) is a low-calorie, low-protein, and low-carbohydrate diet that is high in unsaturated fats. It is designed to affect the body similarly to water-only fasting- when a person does not eat although can drink water freely- while still providing essential nutrients. Previous research has shown that brief and periodic cycles of FMD have beneficial physiological effects in both mice and humans. These effects include a reduced risk of cancer, heart disease, and diabetes.
In the current study, the researchers set out to see whether an FMD diet could limit the progression of Alzheimer's disease in mice. To do so, they studied two models of mice genetically engineered to develop the illness alongside non-Alzheimer's prone controls.
The genetically engineered mice were split into two groups and either received an FMD diet or a standard diet alongside controls. Each FMD cycle lasted around 4-5 days, before and after which mice were fed standard diets. Mice typically underwent 2 FMD cycles per month. The researchers conducted several experiments with the mice, ultimately assessing the effects of one FMD cycle up to 30 cycles over 15 months.
In the end, they found that mice who underwent FMD cycles had decreased levels of amyloid beta and tau protein in their brains- hallmarks of Alzheimer's disease- compared to mice on a standard diet. They also had less brain inflammation compared to genetically engineered mice fed a standard diet.
Those that underwent FMD also performed significantly better on cognitive tests than genetically-engineered mice on standard diets. The researchers further noted that, at times, they even performed similarly to the control mice, implying that FMD may have the potential to significantly reverse cognitive defects.
The researchers also included data from a Phase 1 clinical trial of the FMD in 40 human patients diagnosed with either Alzheimer's disease or mild cognitive impairment. They noted that while intervention is safe and feasible for these patients, further tests are needed to assess resulting levels of inflammation and cognitive performance.