Belly fat speeds brain aging

Ben-Gurion University of the Negev said on May 4 that a long-term MRI study found lower accumulation of visceral abdominal fat was associated with slower brain atrophy and better cognitive performance in late midlife. The findings were published in Nature Communications and were based on repeated MRI scans of the brain and abdomen in 533 women and men followed for 5 to 16 years. The researchers said the association held independently of overall weight loss, pointing instead to the amount of fat stored deep around internal organs. Prof. Iris Shai, who led the dietary trials behind the cohort, said the results identify visceral fat and glucose control as measurable targets in midlife. ### Which fat did the researchers say mattered most? The Ben-Gurion team said visceral fat — the fat stored deep in the abdomen around organs — was the measure most consistently linked to later brain changes. In the study, lower long-term accumulation of visceral fat was associated with preserved total brain volume, preserved gray matter volume and a better hippocampal occupancy score, which the researchers described as a sensitive marker tied to brain aging and memory. (bgu.ac.il) The same report said the association was not seen for subcutaneous fat, whether superficial or deep, and was also not seen for body mass index. That distinction matters because BMI and body weight are broader measures, while the study focused on MRI-based measures of fat distribution inside the abdomen. ### How long were people followed, and what did the scans show? (bgu.ac.il) The study included 533 participants in late midlife who were followed for between 5 and 16 years after taking part in four long-running dietary clinical trials: DIRECT, CASCADE, CENTRAL and DIRECT-PLUS. During follow-up, researchers repeatedly measured visceral fat and brain structure with MRI and assessed cognition with the Montreal Cognitive Assessment, or MoCA. (bgu.ac.il) A subgroup underwent three brain MRI scans over five years, and the university said persistently elevated visceral fat in that group was associated with faster loss of brain volume, especially in the hippocampus, and with faster enlargement of the brain ventricles. The report described ventricular expansion as an established marker of brain atrophy. (bgu.ac.il) ### Did the study say weight loss itself explained the effect? The researchers said reductions in visceral fat during an 18-month dietary intervention predicted better preservation of brain structures 5 and 10 years later, even after adjustment for weight loss and other factors. That means the signal in this study came from changes in abdominal visceral fat rather than from pounds lost alone, according to the university summary and the paper abstract. (bgu.ac.il) Prof. Iris Shai said in the university release that the findings point to “glucose control and reduction of visceral abdominal fat” as practical midlife targets. The same release said the relationship between abdominal fat and brain aging was likely mediated primarily through glucose control and insulin sensitivity. (bgu.ac.il) ### What should readers be careful not to overclaim from this result? Nature Communications published the paper as an observational analysis within long-term dietary trial cohorts, not as proof that belly fat directly causes brain aging in every individual. The study reported an association between sustained visceral fat loss and slower structural brain decline, but the release did not describe it as definitive proof of causation. (bgu.ac.il) The 533 participants came from controlled dietary trials led by Shai and collaborators at Ben-Gurion University, Reichman University, Harvard University, Leipzig University and Tulane University. Because the findings were drawn from that specific cohort and follow-up design, replication in other populations and settings would be the next test of how broadly the results apply. That is an inference from the study design, not a claim the paper itself proves. (nature.com) ### Where did the data come from, and what comes next? Ben-Gurion University said the cohort was built from four named dietary trials and combined repeated abdominal MRI, repeated brain MRI and cognitive testing over years of follow-up. The university described the paper as the first study to link repeated MRI-based measurements of cumulative visceral fat with long-term trajectories of brain aging and cognition. (bgu.ac.il) Nature Communications has already published the study, titled “Sustained visceral fat loss is associated with attenuated brain atrophy and better cognition in late midlife.” The next concrete step for readers who want the primary source is that paper and its methods, along with follow-up work from Ben-Gurion University and collaborating researchers including Iris Shai. (nature.com) (bgu.ac.il)