The traditional diet of Greece and cancer.

[Guest guest]

FYI.

European Journal of Cancer Prevention June 2004;13(3):219-230

The term 'Mediterranean diet', implying that all Mediterranean people have the same diet, is a misnomer. The countries around the Mediterranean basin have different diets, religions and cultures. Their diets differ in the amount of total fat, olive oil, type of meat, wine, milk, cheese, fruits and vegetables; and the rates of coronary heart disease and cancer, with the lower death rates and longer life expectancy occurring in Greece. The diet of Crete represents the traditional diet of Greece prior to 1960. Analyses of the dietary pattern of the diet of Crete shows a number of protective substances, such as selenium, glutathione, a balanced ratio of n-6/n-3 essential fatty acids (EFA), high amounts of fibre, antioxidants (especially resveratrol from wine and polyphenols from olive oil), vitamins E and C, some of which have been shown to be associated with lower risk of cancer, including cancer of the breast. Epidemiological studies and animal experiments indicate that n-3 fatty acids exert protective effects against some common cancers, especially cancers of the breast, colon and prostate. Many mechanisms are involved, including suppression of neoplastic transformation, cell growth inhibition, and enhanced apoptosis and anti-angiogenicity, through the inhibition of eicosanoid production from n-6 fatty acids; and suppression of cyclooxygenase 2 (COX-2), interleukin 1 (IL-1) and IL-6 gene expression by n-3 fatty acids. Recent intervention studies in breast cancer patients indicate that n-3 fatty acids, and docosahexaenoic acid (DHA) in particular, increase the response to chemopreventive agents. In patients with colorectal cancer, eicosapentaenoic acid (EPA) and DHA decrease cell proliferation, and modulate favourably the balance between colonic cell proliferation and apoptosis. These findings should serve as a strong incentive for the initiation of intervention trials that will test the effect of specific dietary patterns in the prevention and management of patients with cancer., © 2004 Lippincott & Wilkins, Inc.

[Guest guest]

--- In , " jwwright " <jwwright@e...>

wrote:

> FYI.

> European Journal of Cancer Prevention June 2004;13(3):219-230

>

> The term 'Mediterranean diet', implying that all Mediterranean

people have

> the same diet, is a misnomer. The countries around the

Mediterranean basin have

> different diets, religions and cultures. Their diets differ

in the amount of

> total fat, olive oil, type of meat, wine, milk, cheese,

fruits and vegetables;

> and the rates of coronary heart disease and cancer, with the

lower death rates

> and longer life expectancy occurring in Greece. The diet of

Crete represents the

> traditional diet of Greece prior to 1960. Analyses of the

dietary pattern of the

> diet of Crete shows a number of protective substances, such

as selenium,

> glutathione, a balanced ratio of n-6/n-3 essential fatty

acids (EFA), high

> amounts of fibre, antioxidants (especially resveratrol from

wine and polyphenols

> from olive oil), vitamins E and C, some of which have been

shown to be

> associated with lower risk of cancer, including cancer of the

breast. Epidemiological

> studies and animal experiments indicate that n-3 fatty acids

exert protective

> effects against some common cancers, especially cancers of

the breast, colon and

> prostate. Many mechanisms are involved, including suppression

of neoplastic

> transformation, cell growth inhibition, and enhanced

apoptosis and anti-angiogenicity,

> through the inhibition of eicosanoid production from n-6

fatty acids; and

> suppression of cyclooxygenase 2 (COX-2), interleukin 1 (IL-1)

and IL-6 gene

> expression by n-3 fatty acids. Recent intervention studies in

breast cancer

> patients indicate that n-3 fatty acids, and docosahexaenoic

acid (DHA) in

> particular, increase the response to chemopreventive agents.

In patients with

> colorectal cancer, eicosapentaenoic acid (EPA) and DHA

decrease cell proliferation,

> and modulate favourably the balance between colonic cell

proliferation and

> apoptosis. These findings should serve as a strong incentive

for the initiation

> of intervention trials that will test the effect of specific

dietary patterns in

> the prevention and management of patients with cancer., ©

2004 Lippincott

> & Wilkins, Inc.

Hi All,

There was much of interest to me in the pdf-available below full

paper,

which is presnted after the media article.

These included:

" Olive oil may not prevent colon cancer because of its

monounsaturated fatty acid (MUFA) content, but

because of its other components such as its anti-oxidants

or phytosterols " .

Giacosa A.

The Mediterranean diet and its protective role against cancer.

Eur J Cancer Prev. 2004 Jun;13(3):155-7. No abstract available.

PMID: 15167212 [PubMed - in process]

The term `the Mediterranean diet' was first popularized

by Ancel Keys in his book How to Eat Well and Stay Well: the

Mediterranean Way, in 1975. This followed the publication

of his studies which showed that Mediterranean countries

have diets associated with low incidence of cardiovascular

disease. Later studies have demonstrated that the

Mediterranean countries also show a low incidence of

cancers of the colon and breast and there is now little

doubt that the Mediterranean countries enjoy a low risk

of many of the diet-related diseases of affluence (Hill and

Giacosa, 1992; Hu, 2003).

The Mediterranean is a large area with many different

diet patterns, but they are all characterized by high

consumption of fruit, vegetables, legumes and dietary

fibre and low intakes of meat and saturated fats. In all of

these respects they agree with the current concepts of a

`healthy diet' and one towards which many countries in

northern Europe are moving (Trichopoulou, 2001).

A further general characteristic of the Mediterranean diet

is the consumption of olive oil, usually in large amounts,

and of fish.

The antioxidant potential of the Mediterranean diet

The Mediterranean diet not only produces favourable

effects on blood lipids but also protects against oxidative

stress. Oxidative damage is thought to represent one of

the mechanisms leading to chronic diseases such as

atherosclerosis and cancer. Many studies suggest that a

link exists between fruit and vegetables or the amounts of

plasma antioxidant vitamins (ascorbic acid, tocopherol

and carotenoids) and risk of death from cancer or coronary

heart diseases. Although emphasis has been given to

different components of the diet, attention has recently

shifted to the diet as a whole. The Mediterranean diet is

able to modulate oxidative stress through complex

mechanisms and not just the high antioxidant compound

content. The preference for fresh fruit and vegetables in

the Mediterranean diet will result in a higher consump-tion

of raw foods, a lower production of cooking-related

oxidants and a consequent decreased waste of nutritional

and endogenous antioxidants. The high intake of anti-

oxidants and fibre helps to scavenge even the small

amount of oxidants or oxidized compounds (Ghiselli et al.,

1997).

Mediterranean diet and DNA adducts

The interaction between environmental carcinogenic

exposures and genetic and acquired susceptibility, such

as polymorphism of metabolizing enzymes and of DNA

repair enzymes, age at starting carcinogen exposure,

gender and ethnicity, may play an important role in most

human cancers (Perera, 1997). Nutritional factors,

including low intake of saturated fat and high consump-tion

of fruit and vegetables, may change an individual's

risk of cancer, particularly of epithelial tumours, in a

favourable direction (Potter and Steinmetz, 1996; La

Vecchia and Tavani, 1998). A general protective effect

against cancer at different sites in the body has been

suggested for a number of fruit and vegetables, including

fresh fruit and vegetables, cruciferous and leek vegetables

(Potter and Steinmetz, 1996).

There are a number of biologically active chemicals in

fruit and vegetables that may potentially reduce the

likelihood of cancer, such as carotenoids, ascorbate,

tocopherols, isothiocyanates, phenols and selenium (Pot-ter

and Steinmetz, 1996) (Table 1), through a number of

mechanisms, including induction and/or inhibition of

enzymes involved in carcinogen metabolism or in DNA

repair, antioxidant effects, increased apoptosis and

decreased cell proliferation (La Vecchia and Tavani,

1998).

Flavonoids and other phenolic compounds have been

detected in grapes, apples, berries, olive, lettuce, onions,

red wine, olive oil and in other components of the

`Mediterranean diet'. Dietary phenolics, mostly of plant

origin, might protect against cancer by affecting the

kinetics of DNA adduct formations, i.e. by modifying the

cytochrome P450-dependent metabolisms, by inducing

the detoxification or DNA repair pathways or by

antioxidant activity (Malaveille et al., 1996; Peluso and

Vineis, 2000). High intake of cruciferous vegetables, such

as broccoli, cabbage and cauliflower has been associated

with lower bladder cancer risk. Combined intake of

tomatoes, tomato sauce, tomato juice and pizza has been

related to lower prostate cancer risk. High consumption

of tomatoes and tomato-based products, including

spaghetti sauce, tomato soup and tomato paste, has been

associated with lower cancer risk for different anatomic

sites (Giovannucci, 1999).

Broccoli, tomatoes and pizza are typical features of the

`Mediterranean diet' and important dietary sources of

isothiocyanates and lycopene, two phytochemicals that

can act as antioxidants or by inducing detoxifying

enzymes (Giovannucci et al., 1995). Therefore, it is

possible that phytochemicals other than flavonoids may

be additionally or complementarily involved in the

reported protective effects of the `Mediterranean diet'

on leukocyte DNA adduct formations.

The antioxidant/anticancer potential of

phenolic compounds isolated from olive oil

High intakes of dietary fats have been implicated in the

development of a number of diseases, including cancer.

Recently, however, the epidemiologic data linking breast

and colon cancer with total fat intake have not been

upheld. In this regard, evidence is emerging that it is not

only the amount but also the type of dietary fat that is

important in the aetiology of some cancers, with

particular regard to olive oil (La Vecchia et al., 1995;

Franceschi et al., 1996, 1997; Braga et al., 1998), and of fish

oil (Simopoulos, 2001).

For this reason, the phenolic and squalene content of a

range of seasoning oils and their antioxidant potential

were quantitated (Owen et al., 2000a).

Recent studies have shown that olive oil, and in particular

extra virgin olive oil, contains an abundance of phenolic

antioxidants including simple phenols (hydroxytyrosol,

tyrosol), aldehydic secoiridoids, flavonoids and lignans

(acetoxypin resinol, pinoresinol). All of these phenolic

substances are potent inhibitors of reactive oxygen

species attack on, for example, salicylic acid and 2-

deoxyguanosine. Currently, there is growing evidence

that reactive oxygen species are involved in the aetiology

of fat-related neoplasms such as cancer of the breast

and colorectum. A plausible mechanism is a high

intake of O-6 polyunsaturated fatty acids which are

especially prone to lipid peroxidation initiated and

propagated by reactive oxygen species, leading to the

formation (via a,b-unsaturated aldehydes such as trans-4-

hydroxy-2-nonenal) of highly promutagenic exocyclic

DNA adducts.

Previous studies have shown that the colonic mucosa of

cancer patients and those suffering from predisposing

inflammatory conditions, such as ulcerative colitis

and Crohn's disease, generates appreciably higher

quantities of reactive oxygen species compared

with normal tissue. Those studies have been extended

by developing accurate high-performance liquid chroma-tography

(HPLC) methods for the quantitation of

reactive oxygen species generated by faecal matrix (Owen

et al., 2000b). The data show that the faecal matrix

supports the generation of reactive oxygen species

in abundance. As yet, there is a dearth of evidence

linking this capacity to actual components of the

diet which may influence the colorectal milieu. However,

using the newly developed methodology we can demon-strate

that the antioxidant phenolic compounds present

in olive oil are potent inhibitors of free radical generation

by the faecal matrix. This indicates that the study of the

inter-relation between reactive oxygen species and diet-ary

antioxidants is an area of great promise for elucidating

mechanisms of colorectal carcinogenesis and possible

future chemopreventive strategies.

Update on fat consumption and cancer risk

A review of the available data on the relationship between

fat consumption and cancer risk emphasizes the pre-ventive

role of the Mediterranean diet.

General considerations

> There is a shortage of well-designed intervention

studies on the relation between diet and cancer risk.

> Laboratory and animal studies give invaluable

information on, for example, mechanisms of

carcinogenesis, but cannot be used to predict the

effect of diet changes on risk of cancer in humans.

> The Mediterranean region provides valuable evidence

of the effect of a particular dietary pattern on health, in

which dietary fat is not harmful, and may even decrease

the risk of cancer at certain sites.

Colon cancer

> There is no evidence that the total fat or saturated fat

intake is related to colon cancer risk in the

Mediterranean context.

> There is evidence that certain types of fat, for example

olive oil and fish oil, may decrease the risk of colon

cancer.

> Olive oil may not prevent colon cancer because of its

monounsaturated fatty acid (MUFA) content, but

because of its other components such as its anti-oxidants

or phytosterols.

> There is disagreement about the strength of the

association between red meat and colon cancer.

Breast cancer

> Evidence concerning the influence of dietary fats on

breast cancer is inconclusive.

> There is some evidence from case–control studies that

high intakes of MUFAs and polyunsaturated fatty acids

(PUFAs) are associated with a decreased risk of breast

cancer.

> Population-based studies have found that total fat

intakes ranging from 20 to 40% of total energy intake

are not related to breast cancer risk.

Prostate cancer

> There is a little evidence of an association between the

intake of saturated fats and the incidence of prostate

cancer.

Priorities for future research

> More well-designed intervention studies of the

effect of diet change on cancer risk in humans are

needed.

> A better understanding of the interaction between

intake of animal products (e.g. red meat) and protective

factors (e.g. fruit, vegetables, wholegrain cereals) in the

diet are needed.

> An improved understanding of the role of lifestyle in

early life on subsequent cancer risk is needed.

> We need to know more about gene–environment

interactions, and the importance of genetic

polymorphism in determining cancer risk.

> The general increase in male life expectancy in western

countries makes it important to improve our

understanding of prostate cancer.

Conclusion

The Mediterranean diet appears to be a healthy diet,

whose benefits are mainly due to its high antioxidant

potential. The preference for fresh fruit and vegetables,

typical of Mediterranean populations, will result in a

higher consumption of raw foods. This involves a reduced

production of cooking-related oxidants, with a conse-quent

decreased waste of nutritional and endogenous

antioxidants.

The abundance of phenolic compounds and other

antioxidants in typical Mediterranean foods (olive oil,

wine, herbs, fruits and vegetables) increases the palat-ability

of foods, and contributes to cooking-derived

carcinogens and peroxides being present at a low level.

Thus the Mediterranean diet is not only non-toxic, but

health promoting as well.

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