Researchers believe the high antioxidant and omega-3 content in walnuts may have contributed to reduced brain degeneration in mice with Alzheimer's.
The research team, led by Dr. Abha Chauhan of the New York State Institute for Basic Research in Developmental Disabilities, NY, publish their findings in the Journal of Alzheimer's Disease.
Dr. Chauhan notes that in a previous study, she and her colleagues found that an extract in walnuts may have a protective effect against oxidative stress caused by beta-amyloid protein.
Since a build-up of this protein can form beta-amyloid plaques - believed to play a role in the development of Alzheimer's - the team wanted to follow-up their research.
In this latest study, they set out to determine the effects of a walnut-enriched diet on learning skills, memory, anxiety and motor coordination in Alzheimer's mouse models.
For 9-10 months, the mice were fed custom-mixed diets that contained either 6% or 9% walnuts each day. In humans, this is the equivalent to consuming either 1 ounce or 1.5 ounces of walnuts per day. To act as controls, other Alzheimer's mouse models were fed a diet without walnuts.
At the end of the study, all mice were subject to experiments that tested their learning abilities, spatial memory, motor coordination and anxiety-related behavior.
Improvements in learning, memory, anxiety and motor coordination
The researchers found that the Alzheimer's mouse models fed the walnut-enriched diets showed significant improvements in all areas, compared with Alzheimer's mouse models fed the control diet.
The team says it is possible that the high antioxidant content of walnuts - which is around 3.7 mmol per ounce - helped protect brain degeneration in the mice. Furthermore, walnuts are known to be a good source of alpha-linolenic acid (ALA) - a form of omega-3 that has been associated with heart and brain benefits.
More than 5 million Americans are living with Alzheimer's disease. By 2050, this number is expected to almost triple, to 16 million. Could this latest study pave the way for new strategies to prevent and treat the disease?
Dr. Chauhan says:
"These findings are very promising and help lay the groundwork for future human studies on walnuts and Alzheimer's disease - a disease for which there is no known cure.
Our study adds to the growing body of research that demonstrates the protective effects of walnuts on cognitive functioning."
Last year, Medical News Today reported on a study claiming walnuts and walnut oil may reduce the risk of cardiovascular disease, while another study suggested that walnuts may improve the body's reaction to stress.