More Data Tie Diet to Slower Cognitive Decline

Two studies now extend the results of a 2006 paper contending that the Mediterranean diet slows cognitive decline, but the issue is far from settled, according to findings from two studies.

In one study that built on the initial 2006 findings using the same cohort of subjects, Dr. Nikolaos Scarmeas and his associates at Columbia University Medical Center, New York, found that both adherence to the Mediterranean diet and higher levels of physical activity reduced the risk of developing Alzheimer disease (AD).

In the other study, Catherine Féart, Ph.D., of Université Victor Segalen Bordeaux (France) and her associates (including Dr. Scarmeas) found that higher adherence to the Mediterranean diet correlated with slower cognitive decline on one test but not on three others.

Offsetting any benefit was the finding that higher adherence did not reduce the risk of incident dementia.

In an editorial comment that accompanied these reports, Dr. David S. Knopman of the Mayo Clinic, Rochester, Minn., cautioned that clinicians and the public should weigh these findings deliberately and not leap to premature conclusions.

The two studies “provide moderately compelling evidence” in support of the Mediterranean diet, “but following a healthy diet does not occur in isolation,” he noted.

In Dr. Scarmeas' study, 1,880 Manhattan residents participating in an aging study were assessed every 1.5 years from 1992 through 2006.

A total of 282 developed incident AD during that time.

Both higher physical activity and higher adherence to a Mediterranean-type diet were associated with lower risk of AD. Among subjects who had the highest levels of activity and diet adherence, the relative risk of AD was reduced by 35%–44%.

“High physical activity in this cohort of 77-year-old individuals corresponded to approximately 1.3 hours of vigorous activity per week, 2.4 hours of moderate physical activity per week, or 4 hours of light physical activity per week, or a combination thereof… Even this relatively small amount of physical activity was associated with a reduction in risk for developing AD,” Dr. Scarmeas and his colleagues said (JAMA 2009;302:627–37).

In Dr. Féart's study, 1,410 elderly participants in a cohort study of dementia were followed for a median of 4 years. Greater adherence to a Mediterranean-type diet was associated with a slower decline in performance on the Mini Mental State Examination, an index of global cognitive performance.

However, adherence to the healthy diet was not associated with performance on the Isaacs Set Test that assesses semantic verbal fluency abilities and speed of verbal production, the Benton Visual Retention Test that evaluates immediate visual memory, or the Free and Cued Selective Reminding Test that assesses verbal episodic memory.

Moreover, adherence to the Mediterranean diet did not correlate with incident dementia, Dr. Féart and her associates said (JAMA 2009;302:638–48).

In his editorial comment, Dr. Knopman said that the healthy diet's association with improved cognition, much like its association with improved heart disease and cancer profiles, “probably reflect[s] a lifetime of exposure both to the diet and to other healthy behaviors.

“An elderly person's diet is shaped by a life-long set of preferences,” he noted (JAMA 2009;302:686–7).

Dr. Scarmeas' study was supported by the National Institute on Aging. He reported no disclosures. The Féart study was supported in part by Sanofi-Aventis, and Dr. Féart reported no disclosures.

Dr. Knopman reported serving on a data and safety monitoring board for Sanofi-Aventis Pharmaceuticals, for which he received personal compensation.

He will serve on a data and safety monitoring board for Lilly and will receive personal compensation. In addition, Dr. Knopman has served as an investigator for clinical trials sponsored by several pharmaceutical companies.

Two studies now extend the results of a 2006 paper contending that the Mediterranean diet slows cognitive decline, but the issue is far from settled, according to findings from two studies.

In one study that built on the initial 2006 findings using the same cohort of subjects, Dr. Nikolaos Scarmeas and his associates at Columbia University Medical Center, New York, found that both adherence to the Mediterranean diet and higher levels of physical activity reduced the risk of developing Alzheimer disease (AD).

In the other study, Catherine Féart, Ph.D., of Université Victor Segalen Bordeaux (France) and her associates (including Dr. Scarmeas) found that higher adherence to the Mediterranean diet correlated with slower cognitive decline on one test but not on three others.

Offsetting any benefit was the finding that higher adherence did not reduce the risk of incident dementia.

In an editorial comment that accompanied these reports, Dr. David S. Knopman of the Mayo Clinic, Rochester, Minn., cautioned that clinicians and the public should weigh these findings deliberately and not leap to premature conclusions.

The two studies “provide moderately compelling evidence” in support of the Mediterranean diet, “but following a healthy diet does not occur in isolation,” he noted.

In Dr. Scarmeas' study, 1,880 Manhattan residents participating in an aging study were assessed every 1.5 years from 1992 through 2006.

A total of 282 developed incident AD during that time.

Both higher physical activity and higher adherence to a Mediterranean-type diet were associated with lower risk of AD. Among subjects who had the highest levels of activity and diet adherence, the relative risk of AD was reduced by 35%–44%.

“High physical activity in this cohort of 77-year-old individuals corresponded to approximately 1.3 hours of vigorous activity per week, 2.4 hours of moderate physical activity per week, or 4 hours of light physical activity per week, or a combination thereof… Even this relatively small amount of physical activity was associated with a reduction in risk for developing AD,” Dr. Scarmeas and his colleagues said (JAMA 2009;302:627–37).

In Dr. Féart's study, 1,410 elderly participants in a cohort study of dementia were followed for a median of 4 years. Greater adherence to a Mediterranean-type diet was associated with a slower decline in performance on the Mini Mental State Examination, an index of global cognitive performance.

However, adherence to the healthy diet was not associated with performance on the Isaacs Set Test that assesses semantic verbal fluency abilities and speed of verbal production, the Benton Visual Retention Test that evaluates immediate visual memory, or the Free and Cued Selective Reminding Test that assesses verbal episodic memory.

Moreover, adherence to the Mediterranean diet did not correlate with incident dementia, Dr. Féart and her associates said (JAMA 2009;302:638–48).

In his editorial comment, Dr. Knopman said that the healthy diet's association with improved cognition, much like its association with improved heart disease and cancer profiles, “probably reflect[s] a lifetime of exposure both to the diet and to other healthy behaviors.

“An elderly person's diet is shaped by a life-long set of preferences,” he noted (JAMA 2009;302:686–7).

Dr. Scarmeas' study was supported by the National Institute on Aging. He reported no disclosures. The Féart study was supported in part by Sanofi-Aventis, and Dr. Féart reported no disclosures.

Dr. Knopman reported serving on a data and safety monitoring board for Sanofi-Aventis Pharmaceuticals, for which he received personal compensation.

He will serve on a data and safety monitoring board for Lilly and will receive personal compensation. In addition, Dr. Knopman has served as an investigator for clinical trials sponsored by several pharmaceutical companies.

Two studies now extend the results of a 2006 paper contending that the Mediterranean diet slows cognitive decline, but the issue is far from settled, according to findings from two studies.

In one study that built on the initial 2006 findings using the same cohort of subjects, Dr. Nikolaos Scarmeas and his associates at Columbia University Medical Center, New York, found that both adherence to the Mediterranean diet and higher levels of physical activity reduced the risk of developing Alzheimer disease (AD).

In the other study, Catherine Féart, Ph.D., of Université Victor Segalen Bordeaux (France) and her associates (including Dr. Scarmeas) found that higher adherence to the Mediterranean diet correlated with slower cognitive decline on one test but not on three others.

Offsetting any benefit was the finding that higher adherence did not reduce the risk of incident dementia.

In an editorial comment that accompanied these reports, Dr. David S. Knopman of the Mayo Clinic, Rochester, Minn., cautioned that clinicians and the public should weigh these findings deliberately and not leap to premature conclusions.

The two studies “provide moderately compelling evidence” in support of the Mediterranean diet, “but following a healthy diet does not occur in isolation,” he noted.

In Dr. Scarmeas' study, 1,880 Manhattan residents participating in an aging study were assessed every 1.5 years from 1992 through 2006.

A total of 282 developed incident AD during that time.

Both higher physical activity and higher adherence to a Mediterranean-type diet were associated with lower risk of AD. Among subjects who had the highest levels of activity and diet adherence, the relative risk of AD was reduced by 35%–44%.

“High physical activity in this cohort of 77-year-old individuals corresponded to approximately 1.3 hours of vigorous activity per week, 2.4 hours of moderate physical activity per week, or 4 hours of light physical activity per week, or a combination thereof… Even this relatively small amount of physical activity was associated with a reduction in risk for developing AD,” Dr. Scarmeas and his colleagues said (JAMA 2009;302:627–37).

In Dr. Féart's study, 1,410 elderly participants in a cohort study of dementia were followed for a median of 4 years. Greater adherence to a Mediterranean-type diet was associated with a slower decline in performance on the Mini Mental State Examination, an index of global cognitive performance.

However, adherence to the healthy diet was not associated with performance on the Isaacs Set Test that assesses semantic verbal fluency abilities and speed of verbal production, the Benton Visual Retention Test that evaluates immediate visual memory, or the Free and Cued Selective Reminding Test that assesses verbal episodic memory.

Moreover, adherence to the Mediterranean diet did not correlate with incident dementia, Dr. Féart and her associates said (JAMA 2009;302:638–48).

In his editorial comment, Dr. Knopman said that the healthy diet's association with improved cognition, much like its association with improved heart disease and cancer profiles, “probably reflect[s] a lifetime of exposure both to the diet and to other healthy behaviors.

“An elderly person's diet is shaped by a life-long set of preferences,” he noted (JAMA 2009;302:686–7).

Dr. Scarmeas' study was supported by the National Institute on Aging. He reported no disclosures. The Féart study was supported in part by Sanofi-Aventis, and Dr. Féart reported no disclosures.

Dr. Knopman reported serving on a data and safety monitoring board for Sanofi-Aventis Pharmaceuticals, for which he received personal compensation.

He will serve on a data and safety monitoring board for Lilly and will receive personal compensation. In addition, Dr. Knopman has served as an investigator for clinical trials sponsored by several pharmaceutical companies.