Research summaries and what it could mean to us.

Dr. Grandma's Hints on Benefiting from the Mediterranean Diet

In 1975, Dr. Ancel Keys published his book How to Eat Well and Stay Well the Mediterranean Way (1). Dr. Keys' book was based upon research (published in 1970) that he and his colleagues did in 7 countries. When he did his research in the late 1950s and early 1960s is was a radical idea that blood cholesterol level and, therefore, risk of coronary heart disease (CHD) were greatly influenced by what was served at mealtimes.

At the time of Keys research, Greece (especially the island of Crete) had the highest life expectancy in the world (and the lowest rate of CHD - 80 to 90% lower than the US at that time) (2) in spite of consuming an unusually high amount of fat.

Information about Extra Virgin Olive Oil: Although the Mediterranean Diet was declared as early as 1997 in scientific literature as "very close to if not the ideal diet"(3), Americans, as a whole, have not benefited from these findings. The Med Diet is not only nutritious and health promoting, but in addition highly palatable and satisfying.

One factor that may have slowed the adoption of the Med Diet may be that there are many variations (18 countries border the Mediterranean Sea). The peoples of southern Italy, for example, consumed a markedly lower fat diet than the people of Crete.

There is a very thorough review of the variations of the Med Diet in the American Journal of Lifestyle Medicine.(4) Although decades ago the researchers made an argument that embracing the term 'Mediterranean diet,' should not be done until it is better explained (5).

It seems to some public health nutritionists/dietitians, including this writer, that the general public does not need to wait until the scientists argue about the details of the benefits of this eating style. So this March 2009 newsletter article is designed to help you benefit now.

The revival of interest by American nutritionists and Registered Dietitians in what we are calling The Mediterranean Style of Eating stems in part from the fact that the impressive body of research from the past several decades supports consuming more of certain types of foods and less of others; the resulting recommendations for food intake generally constitute what was meant by the term 'Mediterranean diet.'

An additional reason that the Med Diet has been embraced by many knowledgeable dietitions and consumers, is that the Med Diet is really a dietary pattern of eating rather than a recommendation based upon singling out individual nutrients as the underlying rationale for a diet. Like other writers on this subject, Dr Grandma is convinced that the possibility of foods interacting in multiple synergistic protective ways is likely involved in the success of the Med Diet.

The fact is that the Med Diet is rich in plant foods which are good sources of dietary fiber, antioxidants, vitamins, minerals, phenols, flavonoids, phosterols, carotenoids, and polyphenols. It is also known that these substances bestow numerous health benefits, including protection from cancer, diabetes and CHD. This is an excellent reason not to wait to move toward a Mediterranean Style of Eating. In 2005 Pitsavos (6) made the case that it is the balance of food consumption and not the consumption of individual foods that provides the protection against the chronic disease that the Med Dietary pattern offers. One example of the synergism is the potential protective effects of the phenols from olive oil and the quercetin of fruits and vegetables (see last month's newsletter).

During the time of the original Med Diet research it was apparent that the consumption of foods from plant origin, with only modest amounts of animal food sources was a great difference from the US consumption pattern. Traditionally, low consumption of red meats (beef, pork, and lamb) which are high in saturated fat and dietary cholesterol (which cause arteriosclerosis - hardening of the arteries) were consumed relatively infrequently in the various Mediterranean diets. "A characteristic of the traditional Med Diet is the unusually high intake of fruits, vegetables, nuts, legumes, wholegrain cereals, and olive oil; all of which are derived from the plant kingdom."(7)(4)

Keys described the intake of greens by the Mediterranean peoples by stating, "No main meal in the Mediterranean countries is replete without lots of verdure (greens)." Greens are often prepared with virgin olive oil, which itself is an additional source of antioxidants (8).

One of the mainstay explanations of the nature of the Med Diet is the central role of olive oil consumption. In the early 1960s the use of butter and other shortening was virtually unknown; they enjoyed extremely low intake of red meat, and only modest amounts of cheeses and yogurt. Olive oil is a source of high oleic acid (a monounsaturated fatty acid) and in addition, a source of large amounts of antioxidant compounds. Both of these classes of compounds protect the body from arteriosclerosis and ultimately contribute to protection from cardiovascular heart disease. Note that the extra-virgin type of olive oil is less refined and has more of the antioxidant compounds that benefit heart health. In addition, the extra-virgin olive oil is also associated with a reduction of both systolic and diastolic blood pressure (9).

In addition to the extra-virgin olive oil, the Med Diet also includes a good amount of omega-3 fatty acids. Both the plant and marine sources of omega-3 fatty acids have shown to be strongly protective against the risk of myocardial infarction (heart attack) (10).

After reviewing the literature, Brill(4) makes 13 suggestions (see below) for a unified Med Diet which is a primarily plant-based, whole-foods diet filled with an abundance of healthful plant-derived bioactive compounds and a diet that provides a low intake of artery-clogging saturated fat, dietary cholesterol, and trans fat.

More specifically, the necessary components of the unified Med Diet that can be extracted from this review include the following:

1. daily consumption of several servings of whole grains (minimally processed)
2. daily consumption of a variety of vegetables (including root vegetables if desired), with an emphasis on daily intake of dark leafy greens (seasonally fresh)
3. daily consumption of fruit (seasonally fresh)
4. daily consumption of plant foods high in omega-3 fatty acids
5. daily consumption of extra virgin olive oil (used as the main fat)
6. daily consumption of legumes
7. daily consumption of red wine (1 to 2 glasses/d) with meals (optional)
8. daily consumption of a small amount of nuts
9. daily use of antioxidant-rich herbs and spices to flavor foods (such as garlic, onions, dill, oregano, and curry powder)
10. weekly consumption of omega-3- rich fish, at least 2 servings per week
11. weekly consumption of a small amount of low-fat or fat-free dairy (such as flavorful cheeses and yogurt), several servings per week
12. moderate consumption of poultry and eggs (can be less than once per week if desired)
13. occasional consumption of sweets containing refined sugars (can be less than once per week if desired)

In "The Mediterranean diet: science and practice" Public Health Nutr. 2006; 9:105-110, W. C. Willett has estimated that more than 80% of CHD, 70% of stroke, and 90% of type 2 diabetes can potentially be avoided with adherence to the traditional Med Diet together with regular physical activity and not smoking.

Last year, when Joyce and Victor Bunderson, Americans striving to consume a Med Diet visited Greece and the island of Crete, they observed only processed white flour being served and eaten. Olive-oil rich vegetable choices could still be found, but red meat seemed to be plentiful. It is unfortunate that the traditional dietary patterns of those who traditionally consumed the Med Diet are rapidly transitioning to a less healthful Western style of eating.

In addition, the lifestyle of the Mediterranean countries has transitioned to a sedentary one. The result of the move from their previous healthy diet and lifestyle, has already led to an increase in CVD, diabetes, obesity, hypertension and high cholesterol (11,12).

We at Dr. Grandma's can only hope that it will not take them as long to return to the roots of their dietary heritage, as it has for those of us in the US to recognize the benefits of the Med Diet and lifestyle.

References:

1. Keys A, Keys M. How to Eat Well and Stay Well the Mediterranean Way. New York: Doubleday; 1975.
2. Willett WC. The Mediterranean diet: science and practice. Public Health Nutr. 2006;9:105-110.
3. McLaren, DS. The kingdom of the Keyses. Nutrition. 1997;13:249-253.
4. Brill, Janet Bond. The Mediterranean Diet and Your Health. Am J Lifestyle Medicine. 2009: Vol. 3, No. 1: 44-56.
5. Ferro-Luzzi A, Sette S. The Mediterranean diet: an attempt to define its present and past composition. Eur J Clin Nutr. 1989;43:13-29.
6. Pitsavos C, Panagiotakos DB, Tzima N, et al. Adherence to the Mediterranean diet is associated with total antioxidant capacity in healthy adults: the ATTICA study. Am J Clin Nutr. 2005;82:694-699.
7. Trichopoulou A, Costacou T, Bamia C, Trichopoulos D. Adherence to a Mediterranean diet and survival in a Greek population. N Engl J Med. 2003;348: 2599-2608.
8. Keys A. Mediterranean diet and public health: personal reflections. Am J Clin Nutr. 1995;61(suppl):1321S-1323S.
9. Psaltopoulou T, Naska A, Orfanos P, Trichopoulos D, Mountokalakis T, Trichopoulou A. Olive oil, the Mediterranean diet, and arterial blood pressure: the Greek European Prospective Investigation into Cancer and Nutrition (EPIC) study. Am J Clin Nutr. 2004;80:1012-1018.
10. Friberg P, Johansson M. Effects of an omega- 3-enriched Mediterranean diet (modified diet of Crete) versus a Swedish diet. World Rev Nutr Diet. 2007;97:52-66.
11. Belahsen R, Rguibi M. Population health and Mediterranean diet in southern Mediterranean countries. Public Health Nutr. 2006;9(8A):1130-1135.
12. Kafatos A, Diacatou A, Voukiklaris G, et al. Heart disease risk-factor status and dietary changes in the Cretan population over the past 30 y: the Seven Countries Study. Am J Clin Nutr. 1997;65:1882-1886.