Professor of the Practice of Law University of Denver Sturm College of Law

Brain Size Matters

Our brains shrink with age and brain atrophy is correlated with risk of cognitive decline and dementia. 

In 2017, scientists discovered that indigenous Tsimane inhabitants of the Amazon in Bolivia have very low rates of cardiovascular disease in their old age.  Researchers decided to examine their brain health in a new study that scanned the brains of 746 Tsimane people, ages 40-94 (396 males).  They discovered the Tsimane people experience 70% less brain shrinkage than people in Western countries.  The Tsimane people have little access to healthcare, but are very physically active and eat vegetables, fish, and lean meat.  Western lifestyle includes better healthcare, but less activity combined with consumption of high amounts of fat and sugar. 

Researchers concluded that brain atrophy in Westerners is likely due to sedentary lifestyle, along with the consumption of high rates of fat and sugar.

Takeaway: Brain shrinkage may be slowed with a reduction of fat and sugar, and an increase in exercise, fruit, vegetables, and fish.


Andrei Irimia, Ph.D, et al., The Indigenous South American Tsimane Exhibit Relatively Modest Decrease in Brain Volume with Age Despite High Systemic InflammationThe Journals of Gerontology: Series A, 2021,

Neuroscience News, Amazon Indigenous Group’s Lifestyle May Hold a Key to Slowing Down Aging, May 26, 2021,

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