The Mediterranean diet (MD) has its roots with our Greek and Roman ancestors, inhabitants of the Mediterranean region that was the birthplace of modern civilization. The well-known staple of the Mediterranean diet, olive oil, was used by the Ancient Greeks as a substitute for animal fat, a food they deemed unhealthy.
During the last few decades, components of the traditional MD have been adopted around the world. Based on the diets of people living in Greece, southern Italy, Portugal, Cyprus, Spain, and Turkey, the MD has become popular worldwide due to the health benefits associated with following such a diet. Researchers’ initial realization that heart disease was less prevalent in the Mediterranean region led to decades of scientific studies on the MD’s relationship with health and longevity.
Recently, a peer-reviewed study was conducted by Dr. Perez-Lopez and his team from the University of Zaragoza, Spain, in order to determine what the existing scientific literature concludes about the health benefits of the Mediterranean diet [1]. Their examination found that the MD is in fact associated with numerous health benefits, including lower rates of cardiovascular disease, cancer, and cognitive decline associated with age. These health benefits also appear to translate into a longer lifespan for individuals who follow a Mediterranean diet.
Mediterranean Diet Protects Against Cancer
Studies have shown that lycopene, a major component in tomatoes, may have protective properties against cancer [2]. Fish consumption has also been linked to a reduced risk of cancer [3].
The MD is rich in both tomatoes and fish as well as other foods, like fruit, vegetables, and olive oil, which may provide nutrients that can help lower risk of cancer. This was supported by a large study of over 25,000 individuals, in which a correlation was found between adherence to the traditional MD and incidence of cancer. Study participants’ adherence to the MD was assessed on a scale of 0 to 9.
During a follow-up period of about 7.9 years, it was found that just a 2-point increase on the scale assessing diet adherence was associated with a 12% decrease in cancer incidence. Furthermore, an increased consumption of unsaturated fats, such as olive oil, cut the cancer risk by 9% on its own [4].
Mediterranean Diet Helps Maintain Bone Mass
Another health advantage seen in Mediterranean countries is a low incidence of osteoporosis. There is some evidence to suggest that the MD may once again play a role in this health advantage. Data has shown that fruits and grains, included in the MD, may have a protective quality for bone metabolism [5].
Other research has shown that phytoestrogens present in legumes – soy in particular – provide bone protection in the Asiatic population [6]. The MD contains many phytoestrogen-containing legumes, such as lentils, chickpeas, and beans. Vitamin D, vitamin K, folates, and beta carotens are found in fruits and vegetables of the MD, and may help maintain bone mass [7-9].
Oily fish is also a rich source of vitamins A and D. A study of 220 Greek women found that high fish and olive oil intake, combined with little red meat, had a positive association with bone mineral density [10].
Mediterranean Diet May Protect Against Rheumatoid Arthritis
The role of the MD in rheumatoid arthritis is not supported by as much evidence as some of the other health benefits, but a link has been seen in observational studies. For example, a study of individuals following the Orthodox Church’s dietary recommendations found that consumption of both olive oil and fish – typically included in the MD – were inversely associated with rheumatoid arthritis.
Beneficial Components of the Mediterranean Lifestyle
The Mediterranean diet is not a weight-loss program; rather, the term refers to the overall dietary patterns that have existed for centuries in the area around the Mediterranean basin.
While there are many variations on the MD, the dietary patterns of the Mediterranean share certain commonalities: an emphasis on fruits, cooked vegetables and legumes, and whole grains, with moderate intake of wine, nuts, fish, and dairy products like yogurt and cheese. Olive oil is a staple of the MD, with large amounts included in most Mediterranean cuisine.
The MD and its apparent health benefits have been of interest to scientists for decades, and which components of the MD contribute these significant health benefits is something researchers have long been trying to determine.
Olive oil
Olive oil is known to benefit heart health in humans and other animals, with anti-inflammatory effects and a favorable impact on cholesterol regulation and blood pressure. It is thought that the considerable antioxidants contained in olive oil may be responsible for better arterial blood pressure, reduced LDL-cholesterol, improvement in diabetes, and a reduced risk of thrombosis. Although olive oil shares some properties with other seed oils like canola oil, it also has many non-fatty components such as carotenes, phenolics compounds and chlorophyll.
Fruit and vegetables
The antioxidant content of fresh fruits and vegetables is thought to be the reason why eating many fruits and vegetables protects against heart disease and cancer. Tomatoes, which are an integral part of the MD, have received a lot of attentions for their beneficial antioxidant lycopene. They have been shown to protect against many health concerns, including hypertension and cardiovascular disease, ultraviolet rays from the sun, cancer, and other chronic diseases.
Oily ï¬sh and polyunsaturated fats
Oily fish contain omega-3 polyunsaturated fats, which appear to have many and significant health benefits. Omega-3s have anti-inflammatory and vasodilatory properties that benefit heart health, and they also may protect against Alzheimer’s disease [11]. This effect of omega-3 fatty acids on cognition is not surprising, given that one-fifth of the human brain’s dry weight is made up of fatty acids, 20% of which are in the form of omega-3 DHA.
Wine in moderation and the French paradox
The French paradox is an interesting phenomenon used to refer to the low risk of coronary heart disease that is associated with moderate red wine consumption, even if the rest of the diet is high in saturated fat [12]. Red wine contains plant compounds that are powerful antioxidants – called polyphenols – with benefits such as protection from LDL oxidation and inflammation. The polyphenol resveratrol in particular, contained in grapes and red wine, has been shown to have antiaging properties and to prevent tumor growth.
Nuts
Nuts are rich in unsaturated fatty acids and the amino acid arginine, which is known to have cardioprotective benefits. Despite their high fat content, individuals who add nuts to their diet do not have a change in body weight, and actually seem to have a decrease in waist circumference and high blood pressure [13]. Walnuts, rich in the cardiovascular protector alpha-linolenic acid, and other nuts play a role in reducing cardiovascular risk.
The Siesta
In addition to the MD, the practice of taking an afternoon nap or “siesta†in Spain, Hispanic America, and some Mediterranean countries, appears to be associated with reduced coronary mortality. A short siesta, of around 40 minutes, provides a 100% increase in alertness and a 34% improvement in performance. While researchers are discovering the health benefits available from the traditional afternoon nap, siestas are becoming less common as more of the world adopts an Americanized work schedule.
Conclusion
The health benefits associated with the traditional Mediterranean diet are significant, and are derived from adoption of the diet as a whole. Many components of the Mediterranean lifestyle provide health benefits, but it is unlikely that one aspect in particular is responsible for the increase in longevity seen by those who follow the MD. Adding some of the beneficial components of the MD to an otherwise unhealthy diet will not provide the benefit seen by individuals who adhere to the MD as a whole: a 20% lower risk of death over a period of 10 years [14]!
References
1. Faustino R. Pérez-López, Peter Chedraui, Javier Haya, José L. Cuadros. Effects of the Mediterranean diet on longevity and age-related morbid conditions. Maturitas 2009; 64: 67–79.
2. Unlu NZ, Bohn T, Francis DM, Nagaraja HN, Clinton SK, Schwartz SJ. Lycopene from heat-induced cis-isomer-rich tomato sauce is more bioavailable than from all-trans-rich tomato sauce in human subjects. Br J Nutr 2007; 98: 140–6.
3. Tang FY, Cho HJ, Pai MH, Chen YH. Concomitant supplementation of lycopene and eicosapentaenoic acid inhibits the proliferation of human colon cancer cells. J Nutr Biochem 2009; 20: 426–34.
4. Benetou V, Trichopoulou A, Orfanos P, et al. Conformity to traditional Mediterranean diet and cancer incidence: the Greek EPIC cohort. Br J Cancer 2008; 99: 191–5.
5. Prynne CJ, Mishra GD, O’Connell MA, et al. Fruit and vegetable intakes and bone mineral status: a cross sectional study in ï¬ve age and sex cohorts. Am J Clin Nutr 2006; 83: 1420–8.
6. Coxam V. Phyto-oestrogens and bone health. Proc Nutr Soc 2008; 67: 184–95.
7. Kanai T, Takagi T, Masuhiro K, et al. Serum vitamin K level and bonemineral density in post-menopausal women. Int J Gynecol Obstet 1997; 56: 25–30.
8. Wattanapenpaiboon N, Lukito W, Wahlqvist ML, Strauss BJ. Dietary carotenoid intake as a predictor of bone mineral density. Asia Pac J Clin Nutr 2003; 12: 467–73.
9. Pérez-López FR. Vitamin D and its implications for musculoskeletal health in women: an update. Maturitas 2007; 58: 117–37.
10. Kontogianni MD, Melistas L, Yannakoulia M, Malagaris I, Panagiotakos DB, Yiannakouris N. Association between dietary patterns and indices of bone mass in a sample of Mediterranean women. Nutrition 2009; 25: 165–71.
11. Solfrizzi V, Capurso C, D’Introno A, et al. Dietary fatty acids, age-related cognitive decline, and mild cognitive impairment. J Nutr Health Aging 2008; 12: 382–6.
12. Renaud S, de Lorgeril M. Wine, alcohol, platelets, and the French paradox for coronary heart disease. Lancet 1992; 339: 1523–6.
13. PREDIMED Study Investigators. Effect of a Mediterranean diet supplemented with nuts on metabolic syndrome status: one-year results of the PREDIMED randomized trial. Arch Intern Med 2008; 168: 2449–58.
14. Knoops KT, de Groot LC, Kromhout D, et al. Mediterranean diet, lifestyle factors, and 10-year mortality in elderly European men and women: the HALE project. JAMA 2004; 292: 1433–9.
15. http://cancerbattlefield.com/ – Fight cancer with healthy foods.
About the Author
Matthaios Papaconstantinou is a postdoctoral fellow at Washington University School of Medicine in St Louis, MO. A medical researcher, Matthaios was born and raised in Greece and has a particular interest in sharing scientific findings on the benefits of the Mediterranean diet – a diet pattern that is considered by many as the best weight loss diet program. In his website, he offers a nice Comparison of Weight-Loss Diets: Atkins (Low-Carb), Mediterranean or Low-Fat?
