notes by dr Claudio Italiano
cfr Functional foods
Numerous
studies and meta-analyzes have been carried out over the last few decades with
the aim of confirming or refuting the first observations concerning the
Mediterranean diet.
The Lyon Diet Hearth Study verified the positive effect of the Mediterranean diet on all the signs of infarct recurrence in patients with a previous infarction, so as to be interrupted after one year because of the important benefits in terms of risk reduction (cf. cardiovascular risk factors) of recurrence, found in the intervention group, which followed a diet in line with the criteria of the Mediterranean diet, compared to the control group.
The EPIC (European Prospective Investigation into Cáncer) -elderly study,
published in 2005 by Trichopoulou et al., Authoritative for the large number of
healthy people studied (about 500,000), for the accuracy and duration (over 10
years), has shown a direct proportionality between adherence to the
Mediterranean diet and survival with reduction of the risk of early death for
any cause vs increased risk of cancer of the stomach and intestines due to high
consumption of red meat and processed meat, and increased risk of death for
cancer in women with a high fat diet).
In general, some types of cancer (for example colon cancer) seem to have a risk inversely related to the consumption of fruits and vegetables and for years scholars investigate the significance and the reasons for this inverse correlation, even in an attempt to establish preventive measures for the neoplastic pathology, but it must be specified that data emerged from the numerous studies in this regard are not completely univocal.
The 2007 NIH-AARP study provided strong evidence on the beneficial effect of the
Mediterranean diet on the risk of death from any cause, including cardiovascular
disease and cancer.
In 2009, surveys conducted within the NHS (Nurse Health Study) on 74,886 women, confirmed a significant reduction in cardiovascular disease mortality with adherence to the Mediterranean diet. A recent meta-analysis of 12 studies confirmed that strict adherence to the habits inherent in the Mediterranean diet is significantly associated with the state of health, being inversely correlated with general mortality, cardiovascular causes and cancer; there would also be an inverse relationship with Parkinson's and Alzheimer's disease.
A modified Mediterranean diet with a reduced glycemic contribution and enriched with specific plant substances (soy proteins, phytosterols, isoalpha-acids and pro-anthocyanidins) can have positive effects on the insulin and inflammatory response.
A recent study by Yamamoto and coli, has shown that the Mediterranean diet is
suitable for patients with Chronic Inflammatory Bowel Diseases (MICI) to favor
the maintenance of remission in the phases of quiescence; the addition of fish
oil (omega-3) has been shown to reduce inflammation and allow a lower dosage of
anti-inflammatory agents, as well as to improve malnutrition in patients with
chronic intestinal inflammatory diseases.
The major components of the Mediterranean diet
Whole grains, legumes, seeds and fiber
Several studies have highlighted the relationship between a high consumption of
whole grains and the reduced risk of developing type 2 diabetes. Other studies
have proven the beneficial effect of whole grains on cardiovascular risk, so
much so that the American Heart Association recommends 3 or more portions / day.
Among the components responsible for this effect would be digestion-resistant
fibers, starches and oligosaccharides, traces of magnesium, phenolic compounds
and phytoestrogens, folate, vitamin B6, vitamin E.
For example, β-glucan, soluble fiber of oats, modifying intestinal viscosity,
negatively influences the absorption of cholesterol, contributing to lower serum
levels and, by modulating the intestinal absorption of sugars and the glycemic
index of the same, on insulin glico-regulation and on the synthesis of hepatic
cholesterol. Psyllium has a similar effect on intestinal fat absorption and
several researchers support its anticancer effects. They are easy to digest and
their surplus is transformed into subcutaneous fat reserve. Foods particularly
representative of the Mediterranean diet are those rich in glycides such as
bread, pasta, rice, legumes, corn, potatoes, sugar, honey.
One aspect that many believe is closely linked to the Mediterranean diet is a
high glycemic index (measure of the speed with which a food causes the increase
in blood sugar, therefore the magnitude of the insulin response).
A marked reduction in blood pressure was achieved in people who consumed a diet rich in potassium, magnesium, calcium from fruits and vegetables and low-fat dairy products. The potentially beneficial components present in fruits and vegetables are vitamins (in particular folate, vitamins C, E, K), minerals (magnesium, potassium, selenium) and phytochemicals (carotenoids, chlorophyll, fibers, flavonoids, isothiocyanates, lignans and phytosterols).
In particular, the flavonoids, a large family of compounds synthesized by plants having the same chemical structure in common, have aroused the interest of scientists to explain the positive effect of fruits and vegetables: they have an antioxidant effect, they are able to bind metal ions by inhibiting the formation of free radicals, regulating intercellular communication pathways, preserving the normal cell cycle, stimulating phase II of detoxification, inhibiting tumor invasion and angiogenesis, reducing inflammation and platelet aggregation.
Flavonoids are divided into classes: anthocyanins (found in berries, red grapes);
flavanols (tea, cocoa, grapes, berries, apples); flavanoni (citrus fruits);
flavonols (widely distributed among the plants); flavones (parsley, thyme,
celery, peppers); isoflavones (soybeans). Berries, legumes, cocoa and drinks
like wine, beer, tea are also the main source of tannins: they are considered
protective agents of the intestinal mucosa for their local antioxidant action.
Glucosinate, present in cruciferous (cabbage, etc.), are recognized as
protective factors against colon and rectal cancer.
In the Mediterranean diet we have a greater
consumption of polyunsaturated fats, which, as everyone knows, contribute to
reducing the share of saturated fats (contained in meat, cheese, butter, lard,
confectionery, palm oil and coconut oil). essential fats are contained in large
quantities in fish, dried fruit and seeds, sunflower, rapeseed and olive oil.The
importance of the results has led the American Heart Association to recommend
the consumption of two fish meals. per week.
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