Arches. Photo by Daniel Chia
HOPES: Huntington's Outreach Project for Education, at Stanford
Jun
26
2010

The Mediterranean Diet

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The Mediterranean diet, based on the dietary habits of the people of Crete, has become more popular to scientists and consumers, as studies continue to reveal its health benefits. For instance, studies show that the diet increases longevity and decreases the risk of Alzheimer’s disease. These promising results would suggest that studies investigating how the Mediterranean diet affects HD patients would be of interest the HD community. This chapter first discusses the history of the Mediterranean diet, what the diet consists of, and then explains in more detail the results of the diet’s studies.

How was the Mediterranean diet discovered?^

Dr. Ancel Keys and his colleagues were the first to discover that the Mediterranean diet has health benefits for a wide range of diseases. During the early 1950s and late 1960s, while Keys was investigating his hypothesis, the Mediterranean region was recovering from the effects of World War II but was not yet influenced by the rising trend of fast food. Keys formed his hypothesis from his simple observation that the people of the island Crete were in especially good health, largely due to their dietary habits.

What is the Mediterranean diet?^

The ideal Mediterranean diet is based on the dietary patterns of the people of Crete in the early 1950s and late 1960s. The Mediterranean diet, as the name expresses, is characteristic of the foods that are commonly available in this region. For instance, the olive-rich Mediterranean makes it easy and common for the people to include olive oil abundantly in their diet.

The Mediterranean diet consists of 9 parts:

  1. High consumption of monounsaturated fat (mostly in the form of olive oil), rather than saturated fats
    • Examples of foods high in monounsaturated fat are olive oil, canola oil, peanut oil, sesame oil, sunflower oil, and avocados.
    • Examples of foods high in saturated fat are butter, lard, meat, dairy products, coconut oil, and palm kernel oil.
  2. Regular and moderate consumption of alcohol, in the form of red wine during meals.
    • If you are a woman (or a man over age 65), moderate consumption is less than one 5-ounce glass of red wine per day.
    • If you are a man under age 65, moderate consumption is less than two 5-ounce glasses of red wine per day.
    • Drinking over this consumption level can result in increased risk of some cancers.
    • The diet’s regular and moderate consumption of alcohol is not for everyone. If you do not normally drink alcohol, you do not need to start drinking. Do not drink alcohol if your doctor advises you not to do so.
    • To read more about the benefits of red wine, please click here.
  3. High consumption of legumes, nuts, and seeds
    • Examples of legumes are beans, peas, alfalfa, lentils, and peanuts. Nuts, such as almonds, pecans, and walnuts, are low in unsaturated fat but high in calories, so it is recommended to only eat about a handful of nuts per day.
  4. High consumption of non-refined cereals and breads
    • Non-refined cereals and breads incorporate the whole grain (including its bran and germ) into the food product, such that you gain the benefit of the grain’s high fiber. Examples of non-refined cereals and breads are brown rice, popcorn, oatmeal, whole wheat bread, whole wheat flour, whole wheat pasta, bran flakes, and rice cakes.
    • Refined cereals and breads means that the portion of the grain that provides its high fiber (its bran and germ) are removed by machinery. Examples of refined cereals and breads are white bread, white rice, pasta, and sugary cereals.
  5. High consumption of fruits
  6. High consumption of vegetables
  7. Low to moderate consumption of dairy products, mostly in the form of cheese or yogurt
  8. Low consumption of meat and poultry
  9. Moderate to high consumption of fish
    • Fish contain healthy omega-3 fatty acids that are thought to act against the inflammatory effects that exacerbate HD. To learn more about omega-3 fatty acids and HD, please click here.

The Mediterranean Diet Food Pyramid

Remember to stay hydrated, and replace salt with herbs, such as oregano and basil (e.g. oregano, basil, thyme, etc.)

Figure Source: Trichopoulou A. Traditional Mediterranean diet and longevity in the elderly: a review. Public Health Nutrition. 2004 Oct;7(7):943-7. Review.


Why choose the Mediterranean diet?^

Easily adaptable into your lifestyle^

Dietary recommendations for our health often involve the increased consumption of certain nutrients, such as particular vitamins and minerals. However, the Mediterranean diet is different in that it is a dietary pattern, rather than the supplementation of a several nutrients. The benefit of the dietary pattern is that is more easily adaptable to one’s lifestyle, since people normally eat a range of different foods in different amounts, as opposed to the very high consumption of certain nutrients. Furthermore, the foods outlined in the Mediterranean diet are foods that many of us already typically include in our diets. Thus, adhering to the Mediterranean diet would not involve drastically changing from your current dietary habits. Rather, following the Mediterranean diet would translate into cutting down on some foods (such as refined cereals and meat) and changing the portion of foods that you already eat (such as increasing consumption of olive oil and fish). Additionally, studies have shown that the Mediterranean diet is also beneficial to ethnic populations different from those that reside in the Mediterranean area.

Since the Mediterranean diet is a dietary pattern, it is often difficult for scientists to determine exactly which parts of the diet are most beneficial, or which parts could even possibly be harmful. However, the scientific community generally believes that the benefits gained from the diet are not due to one single part of the diet. For example, Scarmeas et al reported that those who had high adherence to the Mediterranean diet were less likely to develop Alzheimer’s disease, with no isolated part of the diet significantly being associated with this health benefit. This finding supports Scarmeas’ hypothesis that “composite dietary patterns can capture dimensions of nutrition that may be missed by individual components.”

Scientific Discoveries of Its Health Benefits^

Although a direct benefit of the Mediterranean diet to HD has not yet been discovered, many studies report benefits of the Mediterranean diet that may be of interest to those with HD, as well as the general population.

Many studies on longevity have found that elderly individuals who follow the Mediterranean diet live longer. For instance, in studies that have taken place among elderly populations in locations such as Greece, Spain, Denmark, and Australia, all participants experienced longevity due to following the Mediterranean diet (see review, Trichopoulou et al). One study, conducted by Knoops et al, showed that elderly individuals, 70 to 90 years old who adhered to the Mediterranean diet and a healthy lifestyle had a lower rate of all-causes and cause-specific mortality by more than a 50% compared to those individuals who were not on the diet. Cause-specific mortality was defined here as mortality due to coronary heart disease, cardiovascular disease, and cancer. However, it must be noted that this mortality statistic is based on not only the Mediterranean diet but also on a healthy lifestyle. Healthy lifestyle was defined by moderate alcohol consumption, nonsmoking, and physical activity. A similar study by Trichopulou et al that measured only the Mediterranean diet’s effect on longevity, with no reference to healthy lifestyle, confirms the findings in the Knoops study.

Perhaps of more interest to those with HD is the finding that adherence to the Mediterranean diet reduces cognitive decline and the risk of Alzheimer’s disease. Panza et al discovered that the Mediterranean diet protected against cognitive decline associated with normal aging of healthy individuals as well as cognitive impairment that characterizes Alzheimer’s disease and vascular disease. One of their results was that those who drank moderate amounts of wine had a lower risk of dementia of Alzheimer’s or vascular origin than those who did not drink any. Similarly, Scarmeas et al found that the group of people that most closely adhered to the Mediterranean diet (highest tertile in scores) reduced their risk of getting Alzheimer’s disease by 40%, compared to those of the lowest tertile in adherence scores.

One of the hypotheses as to how the Mediterranean diet benefits those with Alzheimer’s disease is that the diet protects against inflammation and oxidative stress, which are also thought to be common complications of Huntington’s disease. (For information on inflammation in HD, please click here and for information on oxidative stress and HD please click here.) Consequently, the Mediterranean diet may be helpful in preventing the progression of HD. Studies investigating the specific effects of the Mediterranean diet on HD still need to be conducted.

For further reading^

  • Kawas CH. Comment on Diet and the Risk of Alzheimer’s Disease (Scarmeas). Ann Neurol. 2006 Jun;59(6):877-9.
    This commentary article critiques the successes and limitations of Scarmeas’ study.
  • Knoops KT, de Groot LC, Kromhout D, Perrin AE, Moreiras-Varela O, Menotti A, van Staveren WA. Mediterranean diet, lifestyle factors, and 10-year mortality in elderly European men and women: the HALE project. JAMA. 2004 Sep 22;292(12)1433-9.
    This article found that elderly of ages 70-90 decreased by 50% all-causes mortality and cause-specific mortality by following a healthy lifestyle and Mediterranean diet.
  • Mayo Clinic. Mediterranean diet for heart health . June 21, 2006. http://www.mayoclinic.com/health/mediterranean-diet/CL00011
    This article gives additional examples of which foods satisfy the Mediterranean diet’s requirements.
  • Panza F, Solfrizzi V, Colacicco AM, D’Introno A, Capurso C, Torres F, Del Parigi A, Capurso S, Capurso A. Mediterranean diet and cognitive decline . Public Health Nutr. 2004 Oct;7(7):959-63. Review.
    This article is a little more difficult to understand than the rest. The article discusses the finding that the Mediterranean diet protects against cognitive decline of normal aging as well as that of Alzheimer’s disease and vascular disease.
  • Scarmeas N, Stern Y, Tang MX, Mayeux R, Luchsinger JA. Mediterranean Diet and Risk for Alzheimer’s Disease . Ann Neurol. 2006 Jun;59(6):912-21.
    This article is fairly easy-to-read and details how high adherence to the Mediterranean diet is associated with lowered risk of Alzheimer’s disease.
  • Trichopoulou A, Costacou T, Bamia C, Trichopoulos D. Adherence to a Mediterranean diet and survival in a Greek population. N Engl J Med. 2003 Jun 26;348(26):2599-608.
    This easy-to-read article finds that close adherence to the Mediterranean diet is associated with decreased all-causes mortality and mortality specially caused by cancer and coronary heart disease.
  • Trichopoulou A. Traditional Mediterranean diet and longevity in the elderly: a review. Public Health Nutr. 2004 Oct;7(7):943-7. Review.
    This article is a literature review of several studies investigating the effects of the Mediterranean diet on longevity in the elderly. The article’s language is clear, and the Mediterranean diet was found to increase longevity in the elderly living in Greece , Spain , Denmark , and Australia .
  • Vanitallie TB. Ancel Keys: a tribute. Nutr Metab (Lond). 2005 Feb 14;2(1):4.
    Details the life of Ancel Keys, the founder of the Mediterranean diet.

-C. A. Chen 5-7-07