Thursday, October 23, 2008

The Mediterranean Diet

You may have heard about the Mediterranean Diet and its implications for health. This meta-analysis confirms previous findings, including reductions in mortality from cardiovacular disease(9%), cancer(6%), Parkinson's Disease, and Alzheimers(13%).

In short, the diet focuses on high intakes of legumes vegetables, high cereals, relative absence of red and processed meats, a high ratio for Monunsaturated vs. Saturated Fat, low milk and dairy products.

I have concerns about a high cereal diet and suggest that this is not a necessary component in relation to the health benefits derived from the Mediterranean diet. Cereals tend to contain high levels of omega 6 and this may create an unbalance in relation to omega 3 levels. Additionally, cereals are often high in carbohydrates, thus potentially leading to excess caloric intake.

However I do agree that in general we consume too much processed and red meat. As recent studies have indicated simply reducing protein intake, as opposed to adopting a torturous caloric restriction regime, can confer substantial benefits. We need to be cautious here, in reducing protein intake we may also be depriving ourselves of some essential amino acids.

An important component of the Mediterranean diet is the large amounts of olive oil used. Monounsaturated fats tend to be ignored these days, in my view there is too much emphasis on omega 3's and I have some concerns about high levels of omega 3's in the diet. After all, eskimos may be relatively free of conditions associated with an imbalance of the omega 3 and omega 6 fats, but they also tend to suffer from cerebral hemorrhages in their 60's and 70's. This propensity to bleeding first came to my attention is a wonderful text on lipids: The Fats of Life by Caroline M Pond. You can preview this text at this site. Thanks Google! The Australian Cardiologist, Ross Walker, also makes reference to this in his text The Cell Factor. I highly recommend this text, it contains abundant useful advice and for anyone with a cardiovascular condition it should be recommended reading.

Another reason I am interested in the role of monounsaturated fats is a study I read wherein they induced a cortical lesion in animals and then gave a massive intravenous infusion of monounsaturated fats. The results were remarkable, a huge reduction in lesion size. Unfortunately I cannot find it in my archives. It seems my memory is still better than my damned database.



Adherence to Mediterranean diet and health status: meta-analysis

Updated information and services can be found at:
http://bmj.com/cgi/content/full/337/sep11_2/a1344

ABSTRACT
Objective To systematically review all the prospective cohort studies that have analysed the relation between adherence to a Mediterranean diet, mortality, and incidence of chronic diseases in a primary prevention setting.

Design

Meta-analysis of prospective cohort studies. Data sources English and non-English publications in PubMed, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials from 1966 to 30 June 2008.

Studies reviewed Studies that analysed prospectively the association between adherence to a Mediterranean diet, mortality, and incidence of diseases; 12 studies, with a total of 1 574 299 subjects followed for a time ranging from three to 18 years were included.

Results

The cumulative analysis among eight cohorts (514 816 subjects and 33 576 deaths) evaluating overall mortality in relation to adherence to a Mediterranean diet showed that a two point increase in the adherence score was significantly associated with a reduced risk of
mortality (pooled relative risk 0.91, 95% confidence interval 0.89 to 0.94). Likewise, the analyses showed a beneficial role for greater adherence to a Mediterranean
diet on cardiovascular mortality (pooled relative risk 0.91, 0.87 to 0.95), incidence of or mortality from cancer (0.94,0.92 to 0.96), and incidence of Parkinson’s disease and
Alzheimer’s disease (0.87, 0.80 to 0.96).

Conclusions

Greater adherence to a Mediterranean diet is associated with a significant improvement in health status, as seen by a significant reduction in overall mortality (9%), mortality from cardiovascular diseases (9%), incidence of or mortality from cancer (6%), and
incidence of Parkinson’s disease and Alzheimer’s disease (13%). These results seem to be clinically relevant for public health, in particular for encouraging a Mediterranean-like dietary pattern for primary prevention of major chronic diseases.

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