A new study, published in the journal Cell Reports, shows improvements in overall health and brain health, as well as learning and memory in lab mice that were fed an unrestricted low-protein, high-carbohydrate diet.
Calorie restriction (CR) and low-protein, high-carbohydrate (LPHC) diets improve cardiometabolic health in mice. Wahl et al show that, like healthspan, CR and LPHC diets positively affect hippocampus biology in mice by influencing hippocampus gene expression, nutrient-sensing pathways, dendritic morphology, and cognition. Image credit: Wahl et al, doi: 10.1016/j.celrep.2018.10.070.
“There are currently no effective pharmaceutical treatments for dementia — we can slow these diseases, but we can’t stop them — so it’s exciting that we are starting to identify diets that are impacting how the brain ages,” said study lead author Devin Wahl, PhD candidate at the University of Sydney.
“The research shows for the first time that unrestricted low-protein, high-carbohydrate diets have similar protective benefits for the brain as calorie restriction, which is well known for its longevity benefits although not sustainable in humans.”
“We have close to 100 years of quality research extolling the benefits of calorie restriction as the most powerful diet to improve brain health and delay the onset of neurodegenerative disease in rodents. However, the majority of people have a hard time restricting calories, especially in Western societies where food is so freely available.”
“It shows a lot of promise that we have been able to replicate the same kind of gene changes in the part of the brain responsible for memory that we also see when we severely restrict calories.”
For the study, Wahl and co-authors fed the mice complex carbohydrates derived from starch, and casein protein which is found in cheese and milk.
To assess the brain benefits of the diet the researchers focused on the hippocampus, the region of the brain responsible for learning and memory.
“The hippocampus is usually the first part of the brain to deteriorate with neurodegenerative diseases like Alzheimer’s,” said study senior author Professor David Le Couteur, also from the University of Sydney.
“However, the low-protein, high-carbohydrate diet appeared to promote hippocampus health and biology in the mice, on some measures to an even greater degree than those on the low-calorie diet.”
Learning and memory was assessed via a series of spatial awareness and memory tests, with researchers noting modest improvements in male and female mice at both young and old ages.
“Numerous cultures including the people of Okinawa in Japan and many parts of the Mediterranean have long observed this mix,” Professor Couteur said.
“The traditional diet of Okinawa is around 9% protein, which is similar to our study, with sources including lean fish, soy and plants, with very little beef. Interestingly, one of their main sources of carbohydrate is sweet potato.”
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Devin Wahl et al. 2018. Comparing the Effects of Low-Protein and High-Carbohydrate Diets and Caloric Restriction on Brain Aging in Mice. Cell Reports 25 (8): 2234-2243; doi: 10.1016/j.celrep.2018.10.070
