Stuffing the Belly Could Starve the Mind in Seniors

By Michael Smith, North American Correspondent, MedPage Today
Published: February 12, 2012
Reviewed by Robert Jasmer, MD; Associate Clinical Professor of Medicine, University of California, San Francisco.

Action Points
• Overeating is associated with an increased risk of mild cognitive impairment (MCI) in people 70 or older.
• Note that the study also observed a dose-response pattern, with more calories being associated with a higher risk of MCI.

Overeating is associated with an increased risk of mild cognitive impairment (MCI) in people 70 or older, researchers are reporting.

In a population-based, case-control study, people who consumed more than 2,142, kilocalories a day had nearly twice the risk of MCI as those eating fewer than 1,526 kilocalories a day, according to Yonas Geda, MD, of the Mayo Clinic in Scottsdale, Ariz., and colleagues.

The researchers also observed a dose-response pattern. "The higher the amount of calories consumed each day, the higher the risk of MCI," Geda said in a statement.

The full study is slated for presentation at the annual meeting of the American Academy of Neurology (AAN) in New Orleans in April, but some data were released early.

Geda and colleagues noted that dietary intake has been associated previously with MCI, but the role of daily energy consumption has not been clear.

Indeed, the study is "noteworthy" in that regard, according to Neelum Aggarwal, MD, of Rush University Medical Center in Chicago, who was not part of the research team.

In an email to MedPage Today, Aggarwal, a member of the AAN, said the findings might have clinical implications, as doctors and patients discuss "the links between common healthy living practices [and] overall cognitive function."

The findings might also help the research agenda by highlighting possible mechanisms for the onset of mental decline, she said.

People with MCI are not regarded as having dementia, but they have cognitive deficits that appear to precede the development of such diseases as Alzheimer's.

To understand the links between caloric intake and MCI, Geda and colleagues turned to the Mayo Clinic Study of Aging, a continuing population-based cohort study in Olmsted County, Minn.

They asked a random sample of 1,233 non-demented study participants, ages 70 through 89, to fill out a food frequency questionnaire for the year preceding an interview.

The volunteers included 1,070 cognitively normal people and 163 with MCI, as determined by an expert consensus panel on the basis of published criteria.

The volunteers were divided into three groups, based on the caloric intake derived from their questionnaire answers.

The reference group for subsequent analysis was participants who ate between 600 and 1,526 kilocalories a day. The middle group ate from 1,526 to 2,142.5 kilocalories a day, while the third group ate 2,142.5 to 6,000 kilocalories a day.

Geda and colleagues conducted multivariable logistic regression analyses, adjusting for age, sex, education, depression, apolipoprotein E (APOE) genotype, history of stroke, coronary artery disease, diabetes, and body mass index.

Compared with the reference group, those in the middle group had an elevated risk of MCI, but it did not reach statistical significance (odds ratio 1.05, 95% CI 0.63 to 1.77).

On the other hand, daily energy consumption in the third group was associated with a greater chance of having MCI (OR 2.41, 95% CI 1.51 to 3.86).

There was also a significant trend (P<0.001) for increasing caloric consumption to increase the risk of MCI, they reported.

One implication of the study might be that "cutting calories and eating foods that make up a healthy diet may be a simpler way to prevent memory loss as we age," Geda said.

Aggarwal told MedPage Today the study includes a large number of non-demented people from the general community in the U.S., which might make the results relatively widely applicable.

However, some questions remain including:
• What sort of questionnaire was used and how it was administered and interpreted?
• Was there an effect of male or female sex or race and ethnicity?
• Did the researchers distinguish between amnestic MCI, in which memory is affected, and MCI in which other cognitive domains, such as orientation, language, and executive function, are impaired?

The study was supported by the NIH, the Robert Wood Johnson Foundation, and the Robert H. and Clarice Smith and Abigail van Buren Alzheimer's Disease Research Program.

The authors did not report any conflicts of interest in the AAN abstract.
Primary source: American Academy of Neurology

Source reference:
Geda Y, et al "Caloric intake, aging, and mild cognitive impairment: a population-based study" AAN 2012.