Excessive body fat around the middle linked to smaller brain, study says

Big waist, small brain? If you're too heavy, especially around your middle, you probably have shrunken gray ...

Posted: Jan 10, 2019 5:13 AM
Updated: Jan 10, 2019 5:13 AM

Big waist, small brain? If you're too heavy, especially around your middle, you probably have shrunken gray matter volume in your brain, according to a study published Wednesday in the journal Neurology. Gray matter contains most of your brain's 100 billion nerve cells, while white matter is filled with nerve fibers that connect the brain regions.

"Previous studies have shown associations between gray matter atrophy and risk of developing dementia," study author Mark Hamer, a professor of exercise as medicine at Loughborough University in England, wrote in an email.

Brain science

Diet and nutrition

Diet, nutrition and fitness

Health and medical

Medical diagnostics, screening and testing

Medical fields and specialties

Neurology and neuroscience

Obesity

Weight loss diets

Obesity linked to reduced brain volume in four regions

The study of 9,652 middle-age people in the UK measured body mass index (BMI) and waist-to-hip ratio. BMI is a formula involving a person's weight and height; a BMI score between 18.5 and 24.9 is considered healthy, while above 30 is considered obese. Similarly, the waist-to-hip ratio is scored, and a high score -- above 0.90 for men and above 0.85 for women -- means a person has central obesity, or a bigger belly than hips.

Based on these criteria, nearly one in five of the study participants was found to be obese.

Hamer and his co-researchers also used an MRI to scan participants' brain volume. The researchers factored in age, physical activity, smoking and high blood pressure, all of which might lead to reduced volume.

What did they find? People with higher numbers on both BMI and waist-to-hip ratio had the lowest gray matter volume. "The reductions in brain size increase in a linear fashion as fat around the middle grew larger," Hamer wrote.

In hard numbers, 1,291 people who had a BMI of 30 or higher and a high waist-to-hip ratio had the lowest average gray matter volume, at 786 cubic centimeters; 514 people with a BMI of 30 or higher but without central obesity had an average gray matter volume of 793 cubic centimeters. Meanwhile, 3,025 people with overall healthy scores had an average gray matter volume of 798 cubic centimeters.

The study also showed no real differences in white matter brain volume linked to obesity. However, excess weight was associated with shrinkage in specific regions of the brain: the pallidum, nucleus accumbens, putamen (linked only to a higher BMI) and caudate (linked only to a higher waist-to-hip ratio). All of these brain regions are involved in motivation and reward.

"It's unclear if abnormalities in brain structure lead to obesity or if obesity leads to these changes in the brain," Hamer said.

Potential causes of lower brain volume

Cara Bohon, an assistant professor in the Department of Psychiatry and Behavioral Sciences at the Stanford University School of Medicine, wrote in an email that the study's findings are "not particularly new or surprising."

The study's strength is its size with "a sample of almost 10,000 individuals," wrote Bohon, who was not involved in this research. Previous studies had come to similar conclusions, but few participants were involved, so scientists could not feel confident in the results, she explained.

"One particularly interesting finding is that, among individuals with obesity, those with greater waist to hip ratio (a marker of visceral fat around the abdomen), showed even lower gray matter volume," Bohon said. This connection between reduced brain volume and abdominal fat could suggest that inflammation and vascular factors may be at work.

Because the cause of a connection between brain volume and obesity is still unclear, perhaps something may be causing both, she wrote: "For example, if there are nutritional factors impacting brain volume, these same nutritional factors could be a direct cause of obesity."

Future research should explore inflammation, nutrition and vascular health to better understand potential links between brain health and obesity, she said. Bohon's own research suggests that weight loss can reverse brain changes, as it showed that when people lost weight, whether a lot or a little, brain volume improved.

Hamer said his research will help scientists learn more about how obesity relates to the risk of neurodegenerative disease. "Obesity can have a detrimental impact on a wide range of health parameters," he wrote. "People should strive to maintain normal body weight."

Huntsville
Scattered Clouds
81° wxIcon
Hi: 88° Lo: 72°
Feels Like: 86°
Florence
Clear
80° wxIcon
Hi: 93° Lo: 73°
Feels Like: 85°
Fayetteville
Clear
75° wxIcon
Hi: 83° Lo: 71°
Feels Like: 75°
Decatur
Clear
77° wxIcon
Hi: 93° Lo: 71°
Feels Like: 79°
Scottsboro
Broken Clouds
75° wxIcon
Hi: 92° Lo: 73°
Feels Like: 75°
WAAY Radar
WAAY WAAY-TV Cam
WAAY Temperatures

Alabama Coronavirus Cases

Confirmed Cases: 99926

Reported Deaths: 1781
CountyConfirmedDeaths
Jefferson13258244
Mobile10517207
Montgomery6835149
Madison544734
Tuscaloosa423076
Baldwin365125
Unassigned363064
Shelby330936
Marshall318937
Lee270047
Morgan241118
Etowah216232
DeKalb183013
Calhoun180717
Elmore173138
Walker153964
Houston141912
Russell13872
St. Clair135418
Limestone134913
Dallas133123
Franklin128820
Cullman122712
Colbert120716
Lauderdale118919
Autauga117421
Escambia108717
Talladega104814
Jackson10144
Tallapoosa86579
Chambers84438
Dale83525
Clarke82610
Blount8124
Chilton8097
Butler76736
Coffee7646
Covington73720
Pike7087
Marion58026
Barbour5765
Lowndes57324
Marengo56515
Hale47826
Bullock46611
Winston45711
Perry4454
Washington44312
Bibb4425
Wilcox43210
Monroe4215
Pickens4049
Randolph40310
Conecuh39310
Sumter36418
Lawrence3512
Macon33914
Crenshaw3265
Choctaw28712
Cherokee2758
Henry2643
Clay2635
Geneva2631
Greene25211
Lamar2292
Fayette2125
Cleburne1271
Coosa1033
Out of AL00

Tennessee Coronavirus Cases

Confirmed Cases: 123914

Reported Deaths: 1233
CountyConfirmedDeaths
Shelby23485308
Davidson20722217
Rutherford658955
Hamilton622053
Knox468540
Williamson357725
Sumner344972
Unassigned31424
Out of TN294714
Wilson232123
Bradley195613
Montgomery195213
Sevier18947
Putnam178518
Trousdale15836
Robertson156720
Hamblen140514
Blount131411
Washington12772
Maury12727
Tipton121110
Madison116018
Sullivan103714
Hardeman93017
Bedford92811
Macon86013
Lake7920
Loudon7493
Gibson7266
Bledsoe7081
Fayette7028
Dickson6982
Anderson6936
Dyer6638
Henderson6043
Cheatham5997
Jefferson5844
Obion5794
Lawrence5756
McMinn55320
Coffee5483
Rhea5382
Warren5334
Carter5246
Lauderdale5148
Haywood5106
Greene5048
Roane4852
Hawkins4837
Hardin4828
Cocke4783
Weakley4634
Cumberland4586
Smith4554
Monroe4529
Giles38513
McNairy3815
DeKalb3652
Franklin3324
Carroll3253
Lincoln3091
Marshall3044
White2945
Henry2900
Johnson2850
Claiborne2760
Hickman2730
Crockett2695
Campbell2541
Wayne2282
Marion2274
Chester2232
Decatur2163
Polk2073
Grainger2000
Overton1981
Unicoi1690
Union1620
Benton1591
Cannon1510
Jackson1291
Humphreys1283
Morgan1261
Scott1220
Grundy1142
Meigs1060
Sequatchie1060
Fentress960
Hancock812
Perry810
Clay780
Stewart780
Lewis741
Moore610
Houston590
Pickett371
Van Buren360

Community Events