New cohort studies were published in the last few weeks on the impact of following the Mediterranean diet on the risk of senile dementia. This led me to do a quick review of the research behind the general wisdom that the diet “is good for you.” I summarize what I found here.
I suggest following the Mediterranean diet in numerous places in my treatise ANTI-AGING FIREWALLS – THE SCIENCE AND TECHNOLOGY OF LONGEVITY. I wrote “Consider a Mediterranean Diet which features eating lots of vegetables and fruits, lean protein, fish, whole-grain pasta, lots of olive oil and moderate amounts of red wine.” Actually the Mediterranean Diet (MeDi) is a family of somewhat similar diets commonly followed in different countries bordering the Mediterranean. Key components of the diet from a health viewpoint are described here and include:
§ “Getting plenty of exercise and eating your meals with family and friends
§ Eating a generous amount of fruits and vegetables
§ Consuming healthy fats such as olive oil and canola oil
§ Using herbs and spices instead of salt to flavor foods
§ Eating small portions of nuts
§ Drinking red wine, in moderation, for some
§ Consuming very little red meat
§ Eating fish or shellfish at least twice a week(ref)”
First, as to the new research relating the diet to risk of dementia: An August 12 study 2009 report in JAMA Adherence to a Mediterranean diet, cognitive decline, and risk of dementia is a “ cohort study of 1410 adults (> or = 65 years) from Bordeaux, France, included in the Three-City cohort in 2001-2002 and reexamined at least once over 5 years.” – “CONCLUSIONS: Higher adherence to a Mediterranean diet was associated with slower MMSE (Mini-Mental State Examination) cognitive decline but not consistently with other cognitive tests(ref).” The conclusions were reached based on data adjusted “for age, sex, education, marital status, energy intake, physical activity, depressive symptomatology, taking 5 medications/d or more, apolipoprotein E genotype, cardiovascular risk factors, and stroke.”
A second report in the same issue of JAMA Physical activity, diet, and risk of Alzheimer disease looks at the impact of following the Mediterranean diet in combination with substantial physical activity. This is a “Prospective cohort study of 2 cohorts comprising 1880 community-dwelling elders without dementia living in New York, New York. Standardized neurological and neuropsychological measures were administered approximately every 1.5 years from 1992 through 2006.” Again, the data was adjusted for numerous variables. “Compared with individuals neither adhering to the diet nor participating in physical activity (low diet score and no physical activity; absolute AD (Alzheimer Disease) risk of 19%), those both adhering to the diet and participating in physical activity (high diet score and high physical activity) had a lower risk of AD (absolute risk, 12%; Hazard Ratio, 0.65 [95% CI, 0.44-0.96]; P = .03 for trend). – Conclusion” In this study, both higher Mediterranean-type diet adherence and higher physical activity were independently associated with reduced risk for AD(ref).”
A July 2009 study report looks at Mediterranean diet and mild cognitive impairment. The study is based on data from a multi-ethnic community in New York. “There were 1393 cognitively normal participants, 275 of whom developed MCI (mild cognitive impairment) during a mean (SD) follow-up of 4.5 (2.7) years (range, 0.9-16.4 years).” Subjects were divided into tertiles with respect to their adherence to a Mediterranean diet. “CONCLUSIONS: Higher adherence to the MeDi is associated with a trend for reduced risk of developing MCI and with reduced risk of MCI conversion to AD(ref).”
I mention two other studies relating the MeDi to dementia risk. A 2007 study report of 192 individuals looked at Mediterranean diet and Alzheimer disease mortality . “ CONCLUSION: Adherence to the Mediterranean diet (MeDi) may affect not only risk for Alzheimer disease (AD) but also subsequent disease course: Higher adherence to the MeDi is associated with lower mortality in AD. The gradual reduction in mortality risk for higher MeDi adherence tertiles suggests a possible dose-response effect(ref).” Another 2007 study was on Mediterranean diet, Alzheimer disease, and vascular mediation. “CONCLUSIONS: We note once more that higher adherence to the MeDi is associated with a reduced risk for AD. The association does not seem to be mediated by vascular comorbidity(ref).”
All five of these cohort studies show a consistent correlation between following a MeDi and lower risk of age-related dementia. The studies correlating Mediterranean Diet to lower mortality are even more impressive. Of many relevant publications I cite only two important studies. The first is a 2007 report Mediterranean dietary pattern and prediction of all-cause mortality in a US population: results from the NIH-AARP Diet and Health Study. “Study participants included 214,284 men and 166,012 women. — During follow-up for all-cause mortality (1995-2005), 27,799 deaths were documented. In the first 5 years of follow-up, 5,985 cancer deaths and 3,451 cardiovascular disease (CVD) deaths were reported.” – “The Mediterranean diet was associated with reduced all-cause and cause-specific mortality.” – “. In women, an inverse association was seen with high conformity with this pattern: decreased risks that ranged from 12% for cancer mortality to 20% for all-cause mortality (P = .04 and P < .001, respectively, for the trend). — CONCLUSION: These results provide strong evidence for a beneficial effect of higher conformity with the Mediterranean dietary pattern on risk of death from all causes, including deaths due to CVD and cancer, in a US population(ref).”
The second cohort study looking at MeDi and mortality is Mediterranean diet, lifestyle factors, and 10-year mortality in elderly European men and women: the HALE project. The study “includes 1507 apparently healthy men and 832 women, aged 70 to 90 years in 11 European countries. This cohort study was conducted between 1988 and 2000.” – “CONCLUSION: Among individuals aged 70 to 90 years, adherence to a Mediterranean diet and healthful lifestyle is associated with a more than 50% lower rate of all-causes and cause-specific mortality(ref).”
These and similar reductions in mortality and other benefits of a Mediterranean diet reported in other publications are quite impressive to me. The reasons for following a Mediterranean diet and a healthy lifestyle are not just New-Age fluff.
