Given the myriad problems associated with the obesity epidemic, science has not had much good to say about body fat in recent years. But a new paper in the journal Psychoneuroendocrinology reports heavier women have one advantage over their gaunt girlfriends: They are less likely to experience menopause-related cognitive decline.
The issue of whether there's a connection between menopause and cognition — a term that encompasses awareness, reasoning, perception and judgment — has yet to be conclusively resolved. Some studies report menopausal status has no effect on this key brain function, while others have found the cognitive performance of postmenopausal women is lower than that of premenopausal women.
A research team led by Petra Thilers of the Karolinska Institute and Stockholm University in Sweden have come up with a possible reason for the mixed results. They report one factor moderating cognitive decline may be a woman's body mass index.
The researchers examined 193 women ages 40 through 65, selected from the Betula Project longitudinal study on memory, health and aging. Those taking hormones were excluded from the analyses. Women who had not menstruated in the previous year were considered postmenopausal.
The participants underwent a variety of tests to measure their cognitive functioning, including ones that measured visuospatial abilities (a block-design task), semantic memory (they were asked to choose a synonym for selected words) and episodic memory (a divided-attention exercise in which they were asked to recall simple sets of words).
For both visuospatial ability and episodic memory, normal-weight postmenopausal women showed "more pronounced decline over time than premenopausal women," the researchers report. "Overweight women declined less than normal-weight women on some, but not all, cognitive measures."
The researchers concede their results are counterintutitive, given the overweight women's "lower baseline cognitive performance and the well-known health risk factors associated with obesity." But they note that a 2004 study of Down syndrome patients suggested overweight women's higher level of estrogen post-menopause "may have a protective effect on cognitive performance."
"The main source of estrogen post-menopause is produced in adipose (aka fatty) tissue, resulting in higher levels of both (estrogenic hormones) estradiol and estrone in overweight women," they write. "There was a reliable positive association between BMI and estradiol in the current study."
The researchers do not consider these results conclusive. But their study suggests the presence of fatty tissue may help post-menopausal women keep their estrogen levels up, with enhanced cognitive function a result. If this tentative conclusion is confirmed, it may turn out that for older women, all food is brain food.