Mediterranean diet

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The Mediterranean diet is a modern[1] nutritional recommendation inspired by the traditional dietary patterns of some of the countries of the Mediterranean Basin.


[edit] History

The most commonly-understood version of the Mediterranean diet was presented by Dr. Walter Willett of Harvard University's School of Public Health in the mid-1990s.[2] 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.[3] The diet is often cited as beneficial for being low in saturated fat and high in monounsaturated fat and dietary fiber.[citation needed]

Although it was first publicized in 1945 by the American doctor Ancel Keys stationed in Salerno, Italy, the Mediterranean diet failed to gain widespread recognition until the 1990s. It 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.[4]

One of the main explanations is thought to be the large amount of olive oil used in the Mediterranean diet. Unlike the high amount of animal fats typical to the American diet, olive oil lowers cholesterol levels in the blood.[5] It is also known to lower blood sugar levels and blood pressure.[citation needed] Research indicates olive oil prevents peptic ulcers and is effective in treatment of peptic ulcer disease,[6] and may be a factor in preventing cancer.[7] In addition, the consumption of red wine is considered a possible factor, as it contains flavonoids with powerful antioxidant properties[8].

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[9].

Michael Pollan suggests the explanation is not any particular nutrient, but the combination of nutrients found in unprocessed food.[10]

Dietary factors may be only part of the reason for the health benefits enjoyed by these cultures. Genetics, lifestyle (notably heavy physical labor), and environment may also be involved.[citation needed]

Although green vegetables, a good source of calcium and iron, as well as goat cheese, a good source of calcium, are common in the Mediterranean diet, concerns remain whether the diet provides adequate amounts of all nutrients, particularly calcium and iron.[citation needed]

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.[11] 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.[12]

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. [13] [14] 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. [15]

[edit] Medical research

The Seven Countries Study[16] 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[17] 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.[18]

According to a study published in the British Medical Journal (May 29, 2008), the traditional Mediterranean diet provides substantial protection against type 2 diabetes.[19] 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.[20]

A study published in The New England Journal of Medicine (July 17, 2008) examined the effects of three diets: low-carb, low-fat, and Mediterranean. The study involved 322 participants and lasted for 2 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.[21]

A meta-analysis published in the British Medical Journal (September 12, 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.[22]

[edit] References

  1. ^ Alberto Capatti et al., Italian Cuisine: A Cultural History, p. 106.; Silvano Serventi and Francoise Sabban, Pasta, p. 162.
  2. ^ Burros, Marian (29 March 1995). "Eating Well". New York Times. Archived by Webcite
  3. ^ Willett WC (01 June 1995). "Mediterranean diet pyramid: a cultural model for healthy eating". American Journal of Clinical Nutrition 61 (6): 1402S–6S. PMID 7754995. 
  4. ^ Bruno Simini, "Serge Renaud: from French paradox to Cretan miracle" The Lancet 355:9197:48 (1 January 2000) at Science Direct (subscription)
  5. ^ Mayo Clinic. "Olive Oil: Which Type Is Best?." ScienceDaily 14 August 2007. 19 November 2007
  6. ^ Romero C, Medina E, Vargas J, Brenes M, De Castro A (February 2007). "In vitro activity of olive oil polyphenols against Helicobacter pylori". J Agric Food Chem. 55 (3): 680–6. doi:10.1021/jf0630217. PMID 17263460. 
    "New Potential Health Benefit Of Olive Oil For Peptic Ulcer Disease." ScienceDaily 14 February 2007
  7. ^ Machowetz A, Poulsen HE, Gruendel S, et al (January 2007). "Effect of olive oils on biomarkers of oxidative DNA stress in Northern and Southern Europeans". Faseb J. 21 (1): 45–52. doi:10.1096/fj.06-6328com. PMID 17110467. 
    "New Year's Resolution No. 1: Prevent Cancer, Use Olive Oil." ScienceDaily 12 December 2006.
  8. ^ Baron-Menguy C, Bocquet A, Guihot AL, et al (November 2007). "Effects of red wine polyphenols on postischemic neovascularization model in rats: low doses are proangiogenic, high doses anti-angiogenic". Faseb J. 21 (13): 3511–21. doi:10.1096/fj.06-7782com. PMID 17595348. 
    "Chemical In Red Wine, Fruits And Vegetables May Stop Cancer, Heart Disease, Depending On The Dose." ScienceDaily 1 November 2007.
  9. ^ "Get your Meds: the Mediterranean Diet and Health", Ellen Gooch, Epikouria Magazine, Fall 2005
  10. ^ Pollan, Michael (2008). In Defense of Food: An Eater's Manifesto. Penguin Press HC, The. ISBN 1-59420-145-5. 
  11. ^ Massimo Alberini, Giorgio Mistretta, Guida all'Italia gastronomica, Touring Club Italiano, 1984
  12. ^ Tapper, Richard; Zubaida, Sami (2001). A Taste of Thyme: Culinary Cultures of the Middle East. Tauris Parke Paperbacks. ISBN 1-86064-603-4. 
  13. ^ Brown JM, Shelness GS, Rudel LL (December 2007). "Monounsaturated fatty acids and atherosclerosis: opposing views from epidemiology and experimental animal models". Curr Atheroscler Rep 9 (6): 494–500. doi:10.1007/s11883-007-0066-8. PMID 18377790. 
  14. ^ Rudel LL, Kelley K, Sawyer JK, Shah R, Wilson MD (01 November 1998). "Dietary monounsaturated fatty acids promote aortic atherosclerosis in LDL receptor-null, human ApoB100-overexpressing transgenic mice". Arterioscler Thromb Vasc Biol. 18 (11): 1818–27. PMID 9812923. 
  15. ^ Wong A (2008). "Incident solar radiation and coronary heart disease mortality rates in Europe". Eur J Epidemiol. 23 (9): 609–14. doi:10.1007/s10654-008-9274-y. PMID 18704704. 
  16. ^ "Coronary heart disease in seven countries". Circulation 41 (4 Suppl): I1–211. April 1970. PMID 5442782. 
  17. ^ "Lyon Diet Heart Study". 
  18. ^ de Lorgeril M, Salen P, Martin JL, Monjaud I, Delaye J, Mamelle N. (1999). "Mediterranean diet, traditional risk factors, and the rate of cardiovascular complications after myocardial infarction: final report of the Lyon Diet Heart Study". Circulation 99 (6): 779–85. PMID 9989963. 
  19. ^ Martínez-González MA, de la Fuente-Arrillaga C, Nunez-Cordoba JM, et al (June 2008). "Adherence to Mediterranean diet and risk of developing diabetes: prospective cohort study". BMJ 336 (7657): 1348–51. doi:10.1136/bmj.39561.501007.BE. PMID 18511765. 
  20. ^ The Traditional Mediterranean Diet Protects Against Diabetes Newswise, Retrieved on July 2, 2008.
  21. ^ Shai I, Schwarzfuchs D, Henkin Y, Shahar DR, Witkow S, Greenberg I, Golan R, Fraser D, Bolotin A, Vardi H, Tangi-Rozental O, Zuk-Ramot R, Sarusi B, Brickner D, Schwartz Z, Sheiner E, Marko R, Katorza E, Thiery J, Fiedler GM, Blüher M, Stumvoll M, Stampfer MJ; Dietary Intervention Randomized Controlled Trial (DIRECT) Group. (July 17 2008). "Weight loss with a low-carbohydrate, Mediterranean, or low-fat diet.". N Engl J Med 359: 229–241. doi:10.1056/NEJMoa0708681. PMID 18635428. 
  22. ^ Sofi F, Cesari F, Abbate R, Gensini GF, Casini A (2008). "Adherence to Mediterranean diet and health status: meta-analysis". BMJ (Clinical research ed.) 337: a1344. doi:10.1136/bmj.a1344. PMID 18786971. PMC: 2533524. 

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