Growing Brains: Potential Good News for Some

Recent research conducted by UC Davis Health has shown that human brains are increasing in size, potentially enhancing brain reserve and reducing the risk of dementia. This finding was established through a comparison between individuals born in the 1930s and those born in the 1970s, revealing that the latter group’s brains were 6.6 percent larger. The results of this study were published in JAMA Neurology.

Charles DeCarli, the lead author of the study, suggested that the era in which a person is born could influence the size of their brain and consequently their brain health over the long term. While genetics is a significant factor in brain size, DeCarli noted that external factors such as healthcare, societal, cultural, and educational influences might also contribute.

The methodology behind the study involved analyzing brain MRIs from the Framingham Heart Study (FHS), a project initiated in 1948 in Framingham, Massachusetts, to investigate heart disease trends. The study spanned 75 years and included original participants as well as their subsequent generations, totaling 5,209 men and women aged 30 to 62. MRIs performed between 1999 and 2019 on 3,226 participants (53 percent female, 47 percent male) with an average age of 57 at the MRI time served as the basis for the brain size study.

The findings indicated that the average brain volume for individuals born in the 1930s was 1,234 milliliters, compared to 1,321 milliliters for those born in the 1970s, marking a 6.6 percent increase. Increases were also observed in brain structures such as the white matter, grey matter, and the hippocampus, which is crucial for learning and memory.

The researchers posited that a larger brain size could lead to a lower likelihood of dementia in the aging population. DeCarli explained that the observed increase in brain structures might indicate enhanced brain development and health. He emphasized that a larger brain reserve could help mitigate the impact of age-related brain conditions, including Alzheimer’s disease and other forms of dementia.