Mediterranean diet
Encyclopedia
The Mediterranean diet is a modern nutritional recommendation inspired by the traditional dietary patterns of southern Italy, Crete
and much of the rest of Greece
in the 1960s.
On November 17, 2010, UNESCO
recognized this diet pattern as an Intangible Cultural Heritage of Italy
, Greece, Spain
and Morocco
, thus reinforcing it not only as a fundamental part of their history and background, but also as a great contribution to the world.Despite its name, this diet is not typical of all Mediterranean cuisine. In Northern Italy, for instance, lard
and butter
are commonly used in cooking, and olive oil is reserved for dressing salads and cooked vegetables. In North Africa, wine is traditionally avoided by Muslims. In both North Africa
and the Levant
, along with olive oil, sheep's tail fat and rendered butter (samna
) are traditional staple fats.
The most commonly understood version of the Mediterranean diet was presented, amongst others, by Dr Walter Willett
of Harvard University
's School of Public Health
from the mid-1990s on, including a book for the general public. Based on "food patterns typical of Crete, much of the rest of Greece
, and southern Italy in the early 1960s", this diet, in addition to "regular physical activity," emphasizes "abundant plant foods, fresh fruit as the typical daily dessert, olive oil as the principal source of fat, dairy products (principally cheese and yogurt), and fish and poultry consumed in low to moderate amounts, zero to four eggs consumed weekly, red meat consumed in low amounts, and wine
consumed in low to moderate amounts". Total fat in this diet is 25% to 35% of calories, with saturated fat at 8% or less of calories.
The principal aspects of this diet include high olive oil
consumption, high consumption of legumes, high consumption of unrefined cereals
, high consumption of fruits, high consumption of vegetables, moderate consumption of dairy products (mostly as cheese and yogurt), moderate to high consumption of fish, low consumption of meat and meat products, and moderate wine consumption.
Olive oil is particularly characteristic of the Mediterranean diet. It contains a very high level of monounsaturated fats, most notably oleic acid
, which epidemiological studies suggest may be linked to a reduction in coronary heart disease risk. There is also evidence that the antioxidants in olive oil improve cholesterol regulation and LDL cholesterol reduction, and that it has other anti-inflammatory and anti-hypertensive effects.
stationed in Salerno
, Italy, the Mediterranean diet failed to gain widespread recognition until the 1990s. Objective data showing that Mediterranean diet is healthy first originated from the Seven Countries Study
.
Mediterranean diet is based on what from the point of view of mainstream nutrition
is considered a paradox: that although the people living in Mediterranean countries tend to consume relatively high amounts of fat, they have far lower rates of cardiovascular disease
than in countries like the United States
, where similar levels of fat consumption are found. A parallel phenomenon is known as the French Paradox
.
A diet rich in salads was promoted in England during the early Renaissance
period by Giacomo Castelvetro
in A Brief Account of the Fruits, Herbs and Vegetables of Italy. He attempted, without success, to convince the English to eat more fruits and vegetables.
The Mediterranean diet is often cited as beneficial for being low in saturated fat
and high in monounsaturated fat
and dietary fiber
. One of the main explanations is thought to be the health effects of olive oil included in the Mediterranean diet.
The Mediterranean diet is high in salt content. Foods such as olives, salt-cured cheeses, anchovies, capers, salted fish roe, and salads dressed with olive oil all contain high levels of salt.
The inclusion of red wine is considered a factor contributing to health as it contains flavonoid
s with powerful antioxidant
properties.
Mireille Guiliano
credits the health effects of the Mediterranean diet to factors such as small portions, daily exercise, and the emphasis on freshness, balance, and pleasure in food.
Dietary factors are only part of the reason for the health benefits enjoyed by certain Mediterranean cultures. A healthy lifestyle (notably a physically active lifestyle or labour) is also beneficial. Environment may also be involved. However, on the population level, i.e. for the population of a whole country or a region, the influence of genetics
is rather minimal, because it was shown that the slowly changing habits of Mediterranean populations, from a healthy active lifestyle and Mediterranean diet to a not so healthy, less physically active lifestyle and a diet influenced by the Western pattern diet
, significantly increases risk of heart disease. There is an inverse association between adherence to the Mediterranean diet and the incidence of fatal and non fatal heart disease in initially healthy middle aged adults in the Mediterranean region.
A 10-year study published in the Journal of American Medical Association (JAMA) found that adherence to a Mediterranean diet and healthful lifestyle was associated with more than a 50% lowering of early death rates.
The putative benefits of the Mediterranean diet for cardiovascular health are primarily correlative in nature; while they reflect a very real disparity in the geographic incidence of heart disease, identifying the causal determinant of this disparity has proven difficult. The most popular dietary candidate, olive oil, has been undermined by a body of experimental evidence that diets enriched in monounsaturated fats such as olive oil are not atheroprotective when compared to diets enriched in either polyunsaturated or even saturated fats.
A recently emerging alternative hypothesis to the Mediterranean diet is that differential exposure to solar ultraviolet radiation accounts for the disparity in cardiovascular health between residents of Mediterranean and more northerly countries. The proposed mechanism is solar UVB-induced synthesis of Vitamin D in the oils of the skin, which has been observed to reduce the incidence of coronary heart disease, and which rapidly diminishes with increasing latitude. Interestingly, residents of the Mediterranean are also observed to have very low rates of skin cancer (which is widely believed to be caused by over-exposure to solar UV radiation); incidence of melanoma
s in the Mediterranean countries is lower than in Northern Europe and significantly lower than in other hot countries such as Australia and New Zealand. Its been hypothesized that some components of the Mediterranean diet may provide protection against skin cancer.
A study published in the Archives of General Psychiatry shows that people who followed the Mediterranean diet were less likely to develop depression.
found that Cretan men had exceptionally low death rates from heart disease, despite moderate to high intake of fat. The Cretan diet
is similar to other traditional Mediterranean diets, consisting mostly of olive oil
, bread, abundant fruit and vegetables, fish, and a moderate amount of dairy foods and wine.
The Lyon Diet Heart Study set out to mimic the Cretan diet, but adopted a pragmatic approach. Realizing that some of the people in the study (all of whom had survived a first heart attack) would be reluctant to move from butter to olive oil, they used a margarine based on rapeseed
(canola
) oil. The dietary change also included 20% increases in vitamin C-rich fruit and bread and decreases in processed and red meat. On this diet, mortality from all causes was reduced by 70%. This study was so successful that the ethics committee decided to stop the study prematurely so that the results of the study could be made available to the public immediately.
According to a 2008 study published in the British Medical Journal, the traditional Mediterranean diet provides substantial protection against type 2 diabetes. The study involved over 13 000 graduates from the University of Navarra
in Spain
with no history of diabetes, who were recruited between December 1999 and November 2007, and whose dietary habits and health were subsequently tracked. Participants initially completed a 136-item food frequency questionnaire designed to measure the entire diet. The questionnaire also included questions on the use of fats and oils, cooking methods and dietary supplements. Every two years participants were sent follow-up questionnaires on diet, lifestyle, risk factors, and medical conditions. New cases of diabetes were confirmed through medical reports. During the follow-up period (median 4.4 years) the researchers from the University of Navarra found that participants who stuck closely to the diet had a lower risk of diabetes. A high adherence to the diet was associated with an 83% relative reduction in the risk of developing diabetes.
A 2008 study published in The New England Journal of Medicine examined the effects of three diets: low-carb, low-fat, and Mediterranean. The study involved 322 participants and lasted for two years. The low-carb and Mediterranean diet resulted in the greatest weight loss, 12 lbs and 10 lbs, respectively. The low-fat diet resulted in a loss of 7 lbs. One caveat of the study is that 86% of the study participants were men. The low-carb and Mediterranean diets produced similar amounts of weight loss in the overall study results and in the men. In the remaining participants who were women, the Mediterranean diet produced 3.8 kg (8.4 lbs) more weight loss on average than the low-carb diet.
A meta-analysis
published in the British Medical Journal
in 2008 showed that following strictly the Mediterranean diet reduced the risk of dying from cancer and cardiovascular disease as well as the risk of developing Parkinson's
and Alzheimer's disease
. The results report 9%, 9%, and 6% reduction in overall, cardiovascular, and cancer mortality respectively. Additionally a 13% reduction in incidence of Parkinson's and Alzheimer's diseases is to be expected provided strict adherence to the diet is observed. As well, a 2007 study found that 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.
A study published in the British Medical Journal in 2009 showed some components of the Mediterranean diet, such as high vegetable consumption and low meat and meat product consumption, are more significantly associated with low risk of mortality than other components, such as cereal consumption and fish consumption. As part of the European Prospective Investigation into Cancer and Nutrition study, researchers followed more than 23,000 Greek men and women for 8.5 years to see how various aspects of a Mediterranean diet affect mortality. Moderate alcohol consumption, high fruit and nut consumption, and high legume consumption were also associated with lower risk of mortality.
Mediterranean Diet, articulated into extensive lifestyles interventions in a clinical follow-up study, improves renal artery circulation, decreasing renal resistive index, even without significant modifications of Insulin Resistance. This is a beneficial effect and modifies the pathophysiology of essential hypertension.
Another study (reported on in the news in February 2010) found that the diet may help keep the brain healthy by reducing the frequency of the mini-strokes that can contribute to mental decline.
Mediterranean Diet is becoming a comprehensive popular and successful translational paradigm for the promotion of healthier lifestyles .
A 2011 meta-analysis
published in the Journal of the American College of Cardiology analyzed the results of 50 studies (35 clinical trials, 2 prospective and 13 cross-sectional) covering about 535,000 people to examine the effect of a Mediterranean diet on metabolic syndrome
. The researchers reported that a Mediterranean diet is associated with lower blood pressure, blood sugar, and triglycerides.
Researcher Antonia Trichopoulou and her team made use of data gathered in the Greek
portion of a large-scale European study known as EPIC (European Prospective Investigation into Cancer and Nutrition
). For their study, they focused on nearly 15,000 Greek women who joined the study when they were between the ages of 20 and 86. Each woman answered a detailed food-frequency questionnaire that addressed their usual style of eating within the previous year. They also responded to questions about their lifestyle, including smoking status and amount of physical activity, and their reproductive history. Their Body Mass Index
was calculated and recorded, and those with a history of cancer were excluded from the study.
Using the food-frequency questionnaire, the researchers were able to calculate each woman's adherence to the Mediterranean Diet by assigning a score ranging from 0 to 9. For those components of the diet that are frequently eaten, such as vegetables, legumes or fish, the women received a score of 1 if their intake was above average, and a 0 if their consumption was below average. Similarly, for those components that are less frequently eaten, such as dairy or red meat, those women who ate less than the average amount also received a 1, while those who ate more than the average received a 0. (This scoring system is a standard one used often in studies of The Mediterranean Diet
.)
After a follow-up of 10 years, the researchers compared the incidence of breast cancer with each woman's Mediterranean Diet score. After controlling for such variables as age, smoking status, physical activity, Body Mass Index
and use of hormone replacement therapy
, the researchers found that overall, there was no statistically significant link between higher Mediterranean Diet adherence and the risk of breast cancer
. They then grouped the women in pre- and post-menopausal status at the start of the study and compared their Mediterranean Diet scores with their risk of breast cancer. And they found that for postmenopausal women, those who had high scores on the Mediterranean Diet adherence scale - that of a 6 to 9 - were 41% less likely to develop breast cancer than those whose scores were low - 0 to 3. In fact, an increase of just 2 points on the Mediterranean Diet scale decreased a postmenopausal woman's risk of breast cancer by 22%.
After systematically reviewing every aspect of life on Crete and comparing it to life in mainland Greece and America, Dr. Allbaugh’s work provided some insightful data on heart disease and mortality rates.
Dr. Allbaugh documented that the rates of death in Crete were high, but the primary problem was poor public health infrastructure, poor access to good quality medical care and the availability of drugs to combat infectious diseases such as malaria, typhoid and dysentery.
Dr. Allbaugh’s data had also inadvertently highlighted that the adults of Crete had substantially better rates of heart disease than in America with a third fewer deaths related to cardiovascular disease and just under a third fewer deaths from cancer.
Although no link was made at the time between diet and heart disease, the research found that the number of daily calories eaten by a typical family in Crete was relatively high and was composed of similar components as found in an American diet, but in substantially different food groups and nutrient sources for the main calories:
Crete
Crete is the largest and most populous of the Greek islands, the fifth largest island in the Mediterranean Sea, and one of the thirteen administrative regions of Greece. It forms a significant part of the economy and cultural heritage of Greece while retaining its own local cultural traits...
and much of the rest of Greece
Greece
Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....
in the 1960s.
On November 17, 2010, UNESCO
UNESCO
The United Nations Educational, Scientific and Cultural Organization is a specialized agency of the United Nations...
recognized this diet pattern as an Intangible Cultural Heritage of Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
, Greece, Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
and Morocco
Morocco
Morocco , officially the Kingdom of Morocco , is a country located in North Africa. It has a population of more than 32 million and an area of 710,850 km², and also primarily administers the disputed region of the Western Sahara...
, thus reinforcing it not only as a fundamental part of their history and background, but also as a great contribution to the world.Despite its name, this diet is not typical of all Mediterranean cuisine. In Northern Italy, for instance, lard
Lard
Lard is pig fat in both its rendered and unrendered forms. Lard was commonly used in many cuisines as a cooking fat or shortening, or as a spread similar to butter. Its use in contemporary cuisine has diminished because of health concerns posed by its saturated-fat content and its often negative...
and butter
Butter
Butter is a dairy product made by churning fresh or fermented cream or milk. It is generally used as a spread and a condiment, as well as in cooking applications, such as baking, sauce making, and pan frying...
are commonly used in cooking, and olive oil is reserved for dressing salads and cooked vegetables. In North Africa, wine is traditionally avoided by Muslims. In both North Africa
North Africa
North Africa or Northern Africa is the northernmost region of the African continent, linked by the Sahara to Sub-Saharan Africa. Geopolitically, the United Nations definition of Northern Africa includes eight countries or territories; Algeria, Egypt, Libya, Morocco, South Sudan, Sudan, Tunisia, and...
and the Levant
Levantine cuisine
Levantine cuisine is the traditional cuisine of the Levant, known in Arabic as the Bilad ash-Sham. This region shared many culinary traditions under the Ottoman Empire which continue to be influential today...
, along with olive oil, sheep's tail fat and rendered butter (samna
Ghee
Ghee is a class of clarified butter that originated in South Asia and is commonly used in South Asian cuisine....
) are traditional staple fats.
The most commonly understood version of the Mediterranean diet was presented, amongst others, by Dr Walter Willett
Walter Willett
Walter Willett, MD, DrPH., is an American physician and nutrition researcher. Currently, Willett is the Fredrick John Stare Professor of Epidemiology and Nutrition, and Chair of the Department of Nutrition at Harvard School of Public Health...
of Harvard University
Harvard University
Harvard University is a private Ivy League university located in Cambridge, Massachusetts, United States, established in 1636 by the Massachusetts legislature. Harvard is the oldest institution of higher learning in the United States and the first corporation chartered in the country...
's School of Public Health
Harvard School of Public Health
The Harvard School of Public Health is one of the professional graduate schools of Harvard University, located in the Longwood Area of the Boston, Massachusetts neighborhood of Mission Hill, which is next to Harvard Medical School. HSPH is considered a significant school focusing on health in the...
from the mid-1990s on, including a book for the general public. Based on "food patterns typical of Crete, much of the rest of Greece
Greece
Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....
, and southern Italy in the early 1960s", this diet, in addition to "regular physical activity," emphasizes "abundant plant foods, fresh fruit as the typical daily dessert, olive oil as the principal source of fat, dairy products (principally cheese and yogurt), and fish and poultry consumed in low to moderate amounts, zero to four eggs consumed weekly, red meat consumed in low amounts, and wine
Wine
Wine is an alcoholic beverage, made of fermented fruit juice, usually from grapes. The natural chemical balance of grapes lets them ferment without the addition of sugars, acids, enzymes, or other nutrients. Grape wine is produced by fermenting crushed grapes using various types of yeast. Yeast...
consumed in low to moderate amounts". Total fat in this diet is 25% to 35% of calories, with saturated fat at 8% or less of calories.
The principal aspects of this diet include high olive oil
Olive oil
Olive oil is an oil obtained from the olive , a traditional tree crop of the Mediterranean Basin. It is commonly used in cooking, cosmetics, pharmaceuticals, and soaps and as a fuel for traditional oil lamps...
consumption, high consumption of legumes, high consumption of unrefined cereals
Whole foods
Whole foods are foods that are unprocessed and unrefined, or processed and refined as little as possible, before being consumed. Whole foods typically do not contain added ingredients, such as salt, carbohydrates, or fat. Examples of whole foods include unpolished grains, beans, fruits, vegetables...
, high consumption of fruits, high consumption of vegetables, moderate consumption of dairy products (mostly as cheese and yogurt), moderate to high consumption of fish, low consumption of meat and meat products, and moderate wine consumption.
Olive oil is particularly characteristic of the Mediterranean diet. It contains a very high level of monounsaturated fats, most notably oleic acid
Oleic acid
Oleic acid is a monounsaturated omega-9 fatty acid found in various animal and vegetable fats. It has the formula CH37CH=CH7COOH. It is an odorless, colourless oil, although commercial samples may be yellowish. The trans isomer of oleic acid is called elaidic acid...
, which epidemiological studies suggest may be linked to a reduction in coronary heart disease risk. There is also evidence that the antioxidants in olive oil improve cholesterol regulation and LDL cholesterol reduction, and that it has other anti-inflammatory and anti-hypertensive effects.
History
Although it was first publicized in 1945 by the American doctor Ancel KeysAncel Keys
Ancel Benjamin Keys was an American scientist who studied the influence of diet on health. In particular, he hypothesized that different kinds of dietary fat had different effects on health....
stationed in Salerno
Salerno
Salerno is a city and comune in Campania and is the capital of the province of the same name. It is located on the Gulf of Salerno on the Tyrrhenian Sea....
, Italy, the Mediterranean diet failed to gain widespread recognition until the 1990s. Objective data showing that Mediterranean diet is healthy first originated from the Seven Countries Study
Seven Countries Study
The Seven Countries Study is an important epidemiological study. It is a large longitudinal study. It was the first study to systematically examine the relationships between lifestyle, diet, coronary heart disease and stroke in different populations from different regions of the world...
.
Mediterranean diet is based on what from the point of view of mainstream nutrition
Nutrition
Nutrition is the provision, to cells and organisms, of the materials necessary to support life. Many common health problems can be prevented or alleviated with a healthy diet....
is considered a paradox: that although the people living in Mediterranean countries tend to consume relatively high amounts of fat, they have far lower rates of cardiovascular disease
Cardiovascular disease
Heart disease or cardiovascular disease are the class of diseases that involve the heart or blood vessels . While the term technically refers to any disease that affects the cardiovascular system , it is usually used to refer to those related to atherosclerosis...
than in countries like the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, where similar levels of fat consumption are found. A parallel phenomenon is known as the French Paradox
French paradox
The French Paradox is the observation that French people suffer a relatively low incidence of coronary heart disease, despite having a diet relatively rich in saturated fats...
.
A diet rich in salads was promoted in England during the early Renaissance
Renaissance
The Renaissance was a cultural movement that spanned roughly the 14th to the 17th century, beginning in Italy in the Late Middle Ages and later spreading to the rest of Europe. The term is also used more loosely to refer to the historical era, but since the changes of the Renaissance were not...
period by Giacomo Castelvetro
Giacomo Castelvetro
Giacomo Castelvetro was an Italian refugee, humanist, teacher and travel writer.-Life:Giacomo Castelvetro was born in Modena in 1546 to the banker Niccolò Castelvetro and his wife Liberata Tassoni. Not much is known of his early life. He was smuggled out of Modena with his older brother when he...
in A Brief Account of the Fruits, Herbs and Vegetables of Italy. He attempted, without success, to convince the English to eat more fruits and vegetables.
Health effects
A number of diets have received attention, but the strongest evidence for a beneficial health effect and decreased mortality after switching to a largely plant based diet comes from studies of Mediterranean diet, e.g. from the NIH-AARP Diet and Health Study.The Mediterranean diet is often cited as beneficial for being low in saturated fat
Saturated fat
Saturated fat is fat that consists of triglycerides containing only saturated fatty acids. Saturated fatty acids have no double bonds between the individual carbon atoms of the fatty acid chain. That is, the chain of carbon atoms is fully "saturated" with hydrogen atoms...
and high in monounsaturated fat
Monounsaturated fat
In biochemistry and nutrition, monounsaturated fats or MUFA are fatty acids that have one double bond in the fatty acid chain and all of the remainder of the carbon atoms in the chain are single-bonded...
and dietary fiber
Dietary fiber
Dietary fiber, dietary fibre, or sometimes roughage is the indigestible portion of plant foods having two main components:* soluble fiber that is readily fermented in the colon into gases and physiologically active byproducts, and* insoluble fiber that is metabolically inert, absorbing water as it...
. One of the main explanations is thought to be the health effects of olive oil included in the Mediterranean diet.
The Mediterranean diet is high in salt content. Foods such as olives, salt-cured cheeses, anchovies, capers, salted fish roe, and salads dressed with olive oil all contain high levels of salt.
The inclusion of red wine is considered a factor contributing to health as it contains flavonoid
Flavonoid
Flavonoids , are a class of plant secondary metabolites....
s with powerful antioxidant
Antioxidant
An antioxidant is a molecule capable of inhibiting the oxidation of other molecules. Oxidation is a chemical reaction that transfers electrons or hydrogen from a substance to an oxidizing agent. Oxidation reactions can produce free radicals. In turn, these radicals can start chain reactions. When...
properties.
Mireille Guiliano
Mireille Guiliano
Mireille Guiliano is a French-American author.Mireille wrote French Women Don't Get Fat which reached #1 on the New York Times "Advice, How-to and Miscellaneous: Hardcover bestseller" list, followed by French Women for All Seasons...
credits the health effects of the Mediterranean diet to factors such as small portions, daily exercise, and the emphasis on freshness, balance, and pleasure in food.
Dietary factors are only part of the reason for the health benefits enjoyed by certain Mediterranean cultures. A healthy lifestyle (notably a physically active lifestyle or labour) is also beneficial. Environment may also be involved. However, on the population level, i.e. for the population of a whole country or a region, the influence of genetics
Genetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
is rather minimal, because it was shown that the slowly changing habits of Mediterranean populations, from a healthy active lifestyle and Mediterranean diet to a not so healthy, less physically active lifestyle and a diet influenced by the Western pattern diet
Western pattern diet
The Western pattern diet, also called Western dietary pattern or the meat-sweet diet, is a dietary habit chosen by many people in developed countries, and increasingly in developing countries. It is characterized by high intakes of red meat, sugary desserts, high-fat foods, and refined grains...
, significantly increases risk of heart disease. There is an inverse association between adherence to the Mediterranean diet and the incidence of fatal and non fatal heart disease in initially healthy middle aged adults in the Mediterranean region.
A 10-year study published in the Journal of American Medical Association (JAMA) found that adherence to a Mediterranean diet and healthful lifestyle was associated with more than a 50% lowering of early death rates.
The putative benefits of the Mediterranean diet for cardiovascular health are primarily correlative in nature; while they reflect a very real disparity in the geographic incidence of heart disease, identifying the causal determinant of this disparity has proven difficult. The most popular dietary candidate, olive oil, has been undermined by a body of experimental evidence that diets enriched in monounsaturated fats such as olive oil are not atheroprotective when compared to diets enriched in either polyunsaturated or even saturated fats.
A recently emerging alternative hypothesis to the Mediterranean diet is that differential exposure to solar ultraviolet radiation accounts for the disparity in cardiovascular health between residents of Mediterranean and more northerly countries. The proposed mechanism is solar UVB-induced synthesis of Vitamin D in the oils of the skin, which has been observed to reduce the incidence of coronary heart disease, and which rapidly diminishes with increasing latitude. Interestingly, residents of the Mediterranean are also observed to have very low rates of skin cancer (which is widely believed to be caused by over-exposure to solar UV radiation); incidence of melanoma
Melanoma
Melanoma is a malignant tumor of melanocytes. Melanocytes are cells that produce the dark pigment, melanin, which is responsible for the color of skin. They predominantly occur in skin, but are also found in other parts of the body, including the bowel and the eye...
s in the Mediterranean countries is lower than in Northern Europe and significantly lower than in other hot countries such as Australia and New Zealand. Its been hypothesized that some components of the Mediterranean diet may provide protection against skin cancer.
A study published in the Archives of General Psychiatry shows that people who followed the Mediterranean diet were less likely to develop depression.
Medical research
The Seven Countries StudySeven Countries Study
The Seven Countries Study is an important epidemiological study. It is a large longitudinal study. It was the first study to systematically examine the relationships between lifestyle, diet, coronary heart disease and stroke in different populations from different regions of the world...
found that Cretan men had exceptionally low death rates from heart disease, despite moderate to high intake of fat. The Cretan diet
Cretan diet
Cretan cuisine is the traditional cuisine of the Mediterranean island of Crete.The core of the cuisine consists of food derived from natural sources, whereas food of animal origin was more peripheral in nature. In general, people consumed seasonal products, available in the wider local area, which...
is similar to other traditional Mediterranean diets, consisting mostly of olive oil
Olive oil
Olive oil is an oil obtained from the olive , a traditional tree crop of the Mediterranean Basin. It is commonly used in cooking, cosmetics, pharmaceuticals, and soaps and as a fuel for traditional oil lamps...
, bread, abundant fruit and vegetables, fish, and a moderate amount of dairy foods and wine.
The Lyon Diet Heart Study set out to mimic the Cretan diet, but adopted a pragmatic approach. Realizing that some of the people in the study (all of whom had survived a first heart attack) would be reluctant to move from butter to olive oil, they used a margarine based on rapeseed
Rapeseed
Rapeseed , also known as rape, oilseed rape, rapa, rappi, rapaseed is a bright yellow flowering member of the family Brassicaceae...
(canola
Canola
Canola refers to a cultivar of either Rapeseed or Field Mustard . Its seeds are used to produce edible oil suitable for consumption by humans and livestock. The oil is also suitable for use as biodiesel.Originally, Canola was bred naturally from rapeseed in Canada by Keith Downey and Baldur R...
) oil. The dietary change also included 20% increases in vitamin C-rich fruit and bread and decreases in processed and red meat. On this diet, mortality from all causes was reduced by 70%. This study was so successful that the ethics committee decided to stop the study prematurely so that the results of the study could be made available to the public immediately.
According to a 2008 study published in the British Medical Journal, the traditional Mediterranean diet provides substantial protection against type 2 diabetes. The study involved over 13 000 graduates from the University of Navarra
University of Navarra
The University of Navarra is a private pontifical university based at the southeast border of Pamplona, Spain. It was founded in 1952 by St. Josemaría Escrivá de Balaguer, the founder of Opus Dei as a corporate work of the apostolate of Opus Dei....
in Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
with no history of diabetes, who were recruited between December 1999 and November 2007, and whose dietary habits and health were subsequently tracked. Participants initially completed a 136-item food frequency questionnaire designed to measure the entire diet. The questionnaire also included questions on the use of fats and oils, cooking methods and dietary supplements. Every two years participants were sent follow-up questionnaires on diet, lifestyle, risk factors, and medical conditions. New cases of diabetes were confirmed through medical reports. During the follow-up period (median 4.4 years) the researchers from the University of Navarra found that participants who stuck closely to the diet had a lower risk of diabetes. A high adherence to the diet was associated with an 83% relative reduction in the risk of developing diabetes.
A 2008 study published in The New England Journal of Medicine examined the effects of three diets: low-carb, low-fat, and Mediterranean. The study involved 322 participants and lasted for two years. The low-carb and Mediterranean diet resulted in the greatest weight loss, 12 lbs and 10 lbs, respectively. The low-fat diet resulted in a loss of 7 lbs. One caveat of the study is that 86% of the study participants were men. The low-carb and Mediterranean diets produced similar amounts of weight loss in the overall study results and in the men. In the remaining participants who were women, the Mediterranean diet produced 3.8 kg (8.4 lbs) more weight loss on average than the low-carb diet.
A meta-analysis
Meta-analysis
In statistics, a meta-analysis combines the results of several studies that address a set of related research hypotheses. In its simplest form, this is normally by identification of a common measure of effect size, for which a weighted average might be the output of a meta-analyses. Here the...
published in the British Medical Journal
British Medical Journal
BMJ is a partially open-access peer-reviewed medical journal. Originally called the British Medical Journal, the title was officially shortened to BMJ in 1988. The journal is published by the BMJ Group, a wholly owned subsidiary of the British Medical Association...
in 2008 showed that following strictly the Mediterranean diet reduced the risk of dying from cancer and cardiovascular disease as well as the risk of developing Parkinson's
Parkinson's disease
Parkinson's disease is a degenerative disorder of the central nervous system...
and Alzheimer's disease
Alzheimer's disease
Alzheimer's disease also known in medical literature as Alzheimer disease is the most common form of dementia. There is no cure for the disease, which worsens as it progresses, and eventually leads to death...
. The results report 9%, 9%, and 6% reduction in overall, cardiovascular, and cancer mortality respectively. Additionally a 13% reduction in incidence of Parkinson's and Alzheimer's diseases is to be expected provided strict adherence to the diet is observed. As well, a 2007 study found that 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.
A study published in the British Medical Journal in 2009 showed some components of the Mediterranean diet, such as high vegetable consumption and low meat and meat product consumption, are more significantly associated with low risk of mortality than other components, such as cereal consumption and fish consumption. As part of the European Prospective Investigation into Cancer and Nutrition study, researchers followed more than 23,000 Greek men and women for 8.5 years to see how various aspects of a Mediterranean diet affect mortality. Moderate alcohol consumption, high fruit and nut consumption, and high legume consumption were also associated with lower risk of mortality.
Mediterranean Diet, articulated into extensive lifestyles interventions in a clinical follow-up study, improves renal artery circulation, decreasing renal resistive index, even without significant modifications of Insulin Resistance. This is a beneficial effect and modifies the pathophysiology of essential hypertension.
Another study (reported on in the news in February 2010) found that the diet may help keep the brain healthy by reducing the frequency of the mini-strokes that can contribute to mental decline.
Mediterranean Diet is becoming a comprehensive popular and successful translational paradigm for the promotion of healthier lifestyles .
A 2011 meta-analysis
Meta-analysis
In statistics, a meta-analysis combines the results of several studies that address a set of related research hypotheses. In its simplest form, this is normally by identification of a common measure of effect size, for which a weighted average might be the output of a meta-analyses. Here the...
published in the Journal of the American College of Cardiology analyzed the results of 50 studies (35 clinical trials, 2 prospective and 13 cross-sectional) covering about 535,000 people to examine the effect of a Mediterranean diet on metabolic syndrome
Metabolic syndrome
Metabolic syndrome is a combination of medical disorders that, when occurring together, increase the risk of developing cardiovascular disease and diabetes. It affects one in five people in the United States and prevalence increases with age...
. The researchers reported that a Mediterranean diet is associated with lower blood pressure, blood sugar, and triglycerides.
Researcher Antonia Trichopoulou and her team made use of data gathered in the Greek
Greece
Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....
portion of a large-scale European study known as EPIC (European Prospective Investigation into Cancer and Nutrition
European Prospective Investigation into Cancer and Nutrition
The European Prospective Investigation into Cancer and Nutrition study is a Europe-wide prospective cohort study of the relationships between diet and cancer, as well as other chronic diseases, such as cardiovascular disease...
). For their study, they focused on nearly 15,000 Greek women who joined the study when they were between the ages of 20 and 86. Each woman answered a detailed food-frequency questionnaire that addressed their usual style of eating within the previous year. They also responded to questions about their lifestyle, including smoking status and amount of physical activity, and their reproductive history. Their Body Mass Index
Body mass index
The body mass index , or Quetelet index, is a heuristic proxy for human body fat based on an individual's weight and height. BMI does not actually measure the percentage of body fat. It was invented between 1830 and 1850 by the Belgian polymath Adolphe Quetelet during the course of developing...
was calculated and recorded, and those with a history of cancer were excluded from the study.
Using the food-frequency questionnaire, the researchers were able to calculate each woman's adherence to the Mediterranean Diet by assigning a score ranging from 0 to 9. For those components of the diet that are frequently eaten, such as vegetables, legumes or fish, the women received a score of 1 if their intake was above average, and a 0 if their consumption was below average. Similarly, for those components that are less frequently eaten, such as dairy or red meat, those women who ate less than the average amount also received a 1, while those who ate more than the average received a 0. (This scoring system is a standard one used often in studies of The Mediterranean Diet
Mediterranean diet
The Mediterranean diet is a modern nutritional recommendation inspired by the traditional dietary patterns of southern Italy, Crete and much of the rest of Greece in the 1960s....
.)
After a follow-up of 10 years, the researchers compared the incidence of breast cancer with each woman's Mediterranean Diet score. After controlling for such variables as age, smoking status, physical activity, Body Mass Index
Body mass index
The body mass index , or Quetelet index, is a heuristic proxy for human body fat based on an individual's weight and height. BMI does not actually measure the percentage of body fat. It was invented between 1830 and 1850 by the Belgian polymath Adolphe Quetelet during the course of developing...
and use of hormone replacement therapy
Hormone replacement therapy (menopause)
Hormone replacement therapy is a system of medical treatment for surgically menopausal, perimenopausal and to a lesser extent postmenopausal women...
, the researchers found that overall, there was no statistically significant link between higher Mediterranean Diet adherence and the risk of breast cancer
Breast cancer
Breast cancer is cancer originating from breast tissue, most commonly from the inner lining of milk ducts or the lobules that supply the ducts with milk. Cancers originating from ducts are known as ductal carcinomas; those originating from lobules are known as lobular carcinomas...
. They then grouped the women in pre- and post-menopausal status at the start of the study and compared their Mediterranean Diet scores with their risk of breast cancer. And they found that for postmenopausal women, those who had high scores on the Mediterranean Diet adherence scale - that of a 6 to 9 - were 41% less likely to develop breast cancer than those whose scores were low - 0 to 3. In fact, an increase of just 2 points on the Mediterranean Diet scale decreased a postmenopausal woman's risk of breast cancer by 22%.
Epidemiology
A lesser known but highly skilled scientist named Dr. Leland Allbaugh was appointed Field Director by the Rockefeller Foundation in the early 1950s to investigate the causes of the high rates of death on the Greek island of Crete and to report to the Greek government on a model which could provide sustainable change. It was envisioned that any results could be adopted into model that could then be taken to other countries suffering with similar rates of high mortality and deprivation.After systematically reviewing every aspect of life on Crete and comparing it to life in mainland Greece and America, Dr. Allbaugh’s work provided some insightful data on heart disease and mortality rates.
Dr. Allbaugh documented that the rates of death in Crete were high, but the primary problem was poor public health infrastructure, poor access to good quality medical care and the availability of drugs to combat infectious diseases such as malaria, typhoid and dysentery.
Dr. Allbaugh’s data had also inadvertently highlighted that the adults of Crete had substantially better rates of heart disease than in America with a third fewer deaths related to cardiovascular disease and just under a third fewer deaths from cancer.
Although no link was made at the time between diet and heart disease, the research found that the number of daily calories eaten by a typical family in Crete was relatively high and was composed of similar components as found in an American diet, but in substantially different food groups and nutrient sources for the main calories:
| Sources of calories consumed, by percentage. Crete, Greece and United States, 1948 | |||
| Food Group | Crete Fall 1948 | Greece 1948-1949 | USA 1948-1949 |
| Cereals | 39 | 61 | 25 |
| Potatoes | 4 | 2 | 3 |
| Sugar and honey | 2 | 4 | 15 |
| Pulses and nuts | 7 | 6 | 3 |
| Vegetables and fruits | 11 | 5 | 6 |
| Meat, fish and eggs | 4 | 3 | 19 |
| Dairy products | 3 | 4 | 14 |
| Oils and fats | 29 | 15 | 15 |
| Wine, beer & spirits | 1 | not given | not given |
| Total calories per person per day | 2,547 | 2,477 | 3,129 |
| Sources of protein in the diet, by percentage | |||
| Animal protein | 24 | 19 | 66 |
| Vegetable protein | 76 | 81 | 34 |
See also
- Mediterranean Diet FoundationMediterranean Diet FoundationThe Mediterranean Diet Foundation The Mediterranean Diet Foundation The Mediterranean Diet Foundation (Fundación Dieta Mediterránea (FDM) is a non-profit organization based in Barcelona that aims to promote the study, investigation and dissemination of the benefits of the Mediterranean...
- Cretan dietCretan dietCretan cuisine is the traditional cuisine of the Mediterranean island of Crete.The core of the cuisine consists of food derived from natural sources, whereas food of animal origin was more peripheral in nature. In general, people consumed seasonal products, available in the wider local area, which...
- French ParadoxFrench paradoxThe French Paradox is the observation that French people suffer a relatively low incidence of coronary heart disease, despite having a diet relatively rich in saturated fats...
- Wine and healthWine and healthThe issue of wine and health is a topic of considerable discussion and research. Wine has a long history of use as an early form of medication, being recommended variously as a safe alternative to drinking water, an antiseptic for treating wounds and a digestive aid, as well as a cure for a wide...
- Cuisine of the MediterraneanCuisine of the MediterraneanMediterranean cuisine is the food from the cultures adjacent to the Mediterranean Sea.Whether this is a useful category is disputed:The idea of the ‘standard Mediterranean’ .....
- Israeli cuisineIsraeli cuisineIsraeli cuisine comprises local dishes by Jews native to Israel and dishes brought to Israel by Jews from the Diaspora. Since before the establishment of the State of Israel in 1948, and particularly since the late 1970s, an Israeli Jewish fusion cuisine has developed.Israeli cuisine has adopted,...