Sunday, November 03, 2013
Weight Gain Hurts Memory in Older Women
The more a woman weighs, the worse her memory. No, I am not a chauvinist pig. This claim comes from actual research—by a woman, no less. Diana Kerwin and her colleagues at Northwestern University studied 8,745 women ages 65 to 79 and found that for every one-point increase in female body mass index, the score on a 100 point memory test dropped by one point.
The problem was greatest in women who had put the weight on around the hips, which is fairly typical for weight gain in women. Nobody knows why this is so. Fat deposits may increase the amount of cytokines, which are hormones that can cause inflammation. In a couple of earlier columns I explained how body inflammation, from sore joints or sore throat, for example, can trigger inflammation in the brain. I explained that brains can get inflamed too, irritated from the release of cytokines and other toxins from the brain’s immune cells in response to inflammation. In both genders, these toxins diminish mental capabilities, especially memory. Remember, everything the brain does affects memory (and everything affecting memory affects the brain).
Another obvious possibility is that excess weight often creates vascular problems, and everybody tends to have a problem with circulation in small arteries as they get older. Excess weight is a risk factor for stroke, as well as Alzheimer’s Disease.
This finding about memory loss is just one of many good reasons to lose weight. There are only two ways to lose weight: eat fewer calories and exercise more. Though exercise doesn’t do much to cause weight loss, it has many other benefits (improved circulation of blood to the brain) that can directly benefit memory and cognitive function.
It is not surprising then to learn of recent studies showing that losing weight can improve thinking and memory, in both men and women. John Gunstad, at Kent State University, compared attentiveness and memory test scores in 150 overweight subjects 109 of whom who had bariatric stomach by-pass surgery and 41 controls who did not. Those who lost weight because of gastric bypass surgery showed mental function improvements within 12 weeks after surgery. Those without hypertension improved more than the bariatric patients who had hypertension. Memory performance of the obese controls actually decreased over this period. Gunstad has a U tube video on his work at www.youtube.com/watch?v=gsFP2zAkStU.
Of course bariatric surgery is not without its problems. This surgery can lead to Wernicke's encephalopathy, a condition associated with thiamin or vitamin B1 deficiency. Symptoms of Wernicke's encephalopathy include loss of short-term memory, vision and muscle coordination. Presumably, vitamin supplements prevent this problem.
Most of us lose weight the old fashioned way: diet and exercise. Will weight loss help mental function, especially in people who are overweight but not to the point of obesity? What Gunstad hopes to test next is the possible mental benefit from losing weight through diet and exercise rather than surgery. I suspect he will see a benefit, but it could come from exercise as such rather than the weight loss. As I have reported in earlier columns, normal-weight people see a mental improvement from aerobic exercise.
But up to a point, you can just sit in your lounge chair and munch potato chips and still improve your memory—if you are learning from my book, Memory Power 101.
Gunstad, J. et al. (2013). Improved memory function 12 weeks after bariatric surgery. Surgery for Obesity and Related Diseases. 7 (4): 465-472. http://www.soard.org/article/S1550-7289%2810%2900688-X/abstract
Kerwin, D. R. et al. 2010. The cross-sectional relationship between body mass index, waist–hip ratio, and cognitive performance in postmenopausal women enrolled in the Women's Health Initiative. Journal of the American Geriatrics Society. 58 (8): 1427–1432.
Neurologic Complications Associated with Novel Influenza A (H1N1) Virus Infection in Children. Center for Disease Control, July 24 2009