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to Menu Page~Diets of other cultures. A cultural diet is defined as the diet of any group of people who share beliefs and customs. By this definition, everyone in the United States is a member of some cultural group. For many cultural groups, food plays an important role in maintenance of both spiritual and physical health. The following is a brief overview of several cultural diets--Asian, Mediterranean, and traditional Native American Indian--that are thought to provide some protection against many of the nutritionally related chronic illnesses prevalent among users of the mainstream diet in the United States today. Although there are many more cultural diets than are covered here, solid scientific research has not yet been collected to establish whether they provide any particular health benefits.
Asian diet. This diet is consumed predominantly by people living in China, Southeast Asia, Korea, and Japan. Rice is a staple and the center of the meal, and there is little or no use of dairy products. Soybean products are important sources of protein and calcium. Dishes incorporate many different ingredients and may be stir-fried or steamed. This diet, in its traditional form, is low in fat and high in carbohydrates and sodium (Kittler and Sucher, 1989).~Mediterranean diet. The Mediterranean Basin is geographically defined as an inland sea that touches three continents--Europe, Asia, and Africa--and is surrounded by 15 almost contiguous countries: Spain, France, Italy, the former Yugoslavia, Albania, Greece, Turkey, Syria, Lebanon, Israel, Egypt, Libya, Tunisia, Algeria, and Morocco. Divided by language and, historically, by political and religious conflict, the Mediterranean countries have for centuries been joined by a similar diet of daily staples.
The Mediterranean diet consists of a daily intake of grains, potatoes, pasta, greens and other vegetables, fruit, beans and other legumes (e.g., lentils, split peas), nuts, cheese, and yogurt. Fish, poultry, eggs, sweets, and red meat are eaten less frequently. However, olive oil and garlic are almost always consumed in abundance (Spiller, 1991). In the case of Spain, France, and Italy, it is their southernmost parts that are considered Mediterranean, defined by their use of olive oil.
Another important aspect of the Mediterranean diet is its emphasis on less refined complex carbohydrates (e.g., pasta) in place of sugar and the highly refined starches generally ~consumed in the United States, even though direct evidence for benefit in reducing disease risk is limited. Anticipated reductions in colon cancer by diets high in grain fiber diets have been difficult to document epidemiologically, although inverse associations with vegetables have been seen repeatedly. However, reduced constipation and reduced risk of colonic diverticular disease are clear benefits (Willett et al., 1990).
It is interesting to note that in the northern areas of many of the European Mediterranean countries, where there is more use of butter, other animal fats, and meat, there is also a higher incidence of cancer (La Vecchia, 1993).
Traditional Native American Indian diet. Many foods used throughout the world today were probably first used by Indians of North, Central, and South America--for example, beans, corn, cranberries, peanuts, peppers, potatoes, pumpkin, squash, and tomatoes. Today, Native American Indians live in areas that are vastly different from one another, so there is no single typical diet. In fact, traditional diets are prepared infrequently except for ceremonial occasions. This is true even for the Arizona Hopi, who still live in old villages that their ~ancient ancestors inhabited (Kuhnlein and Calloway, 1977). Nevertheless, in many American Indian diets, corn is the staple food. It is eaten fresh roasted or boiled, as hominy, or as cornmeal in a variety of dishes. Meat is eaten when it can be obtained by hunting or fishing, but because it is so expensive to buy, it is used sparingly. Milk and dairy products are not used often because of a high incidence of lactose intolerance (lactose is the primary sugar in milk). Berries, wild plants, and roots are used when available (Robinson and Lawler, 1982).
Research base. The following provides an overview of research on the effectiveness of some components of the Asian, Mediterranean, and traditional Native American Indian diets in lowering some risk factors for disease.
Asian diet. In a cohort study of 265,000 people in Japan, consumption of miso soup (a food made from soybeans) appeared to reduce the risk of breast cancer (Hirayama, 1986) and stomach cancer (Hirayama, 1981). A similar inverse association was seen between stomach cancer and tofu intake (Hirayama, 1971). Furthermore, miso has been observed to inhibit ~formation of mammary tumors in rodents (Baggott et al., 1990) and may have antioxidant properties as well (Santiago et al., 1992).
Antioxidant properties have been proposed as a principal mechanism by which dietary compounds such as beta-carotene, vitamin E, indoles, and others exert cancer-preventive effects (Steinmetz and Potter, 1991a, 1991b). It has also been suggested that sea vegetables, perhaps through their high concentration of alginic acid, a type of dietary fiber, may decrease the risk of breast cancer (Teas et al., 1984; Yamamoto et al., 1987). Beans and bean products, especially those derived from soybeans (e.g., miso, tofu, tempeh), also contain protease inhibitors (Messina and Barnes, 1991), isoflavonoids (Adlercreutz et al., 1987), and other compounds that may play roles in cancer prevention (Axelson et al., 1984).
Mediterranean diet. The high consumption of olive oil is considered a major contributor to the disease-preventive aspects of this diet. Olive oil is a monounsaturated fat, meaning that somewhere along the fat, or fatty acid, molecule there is a single site not completely ~"saturated" with hydrogen atoms. Substituting monounsaturated fats, such as olive oil, for saturated fat in the diet has been shown to reduce LDL cholesterol without affecting HDL cholesterol, thus providing an improved ratio (Mensink and Katan, 1992). In addition, monounsaturated fats in the diet have been found to reduce blood sugar and triglycerides in adult-onset diabetics (Garg et al., 1992).
In one of the first studies of its kind, researchers in France placed approximately 300 patients who had recently had a heart attack (myocardial infarction) on a Mediterranean type of diet and compared their incidence of having a second myocardial infarction with that of a control group of patients who were placed on the standard therapeutic diet. The experimental group consumed significantly more bread and fruit, a margarine with a fatty acid composition comparable to that of olive oil, and significantly less butter, cream, and meat than the control group. After a followup of about 27 months, there were only 3 cardiac deaths and 5 nonfatal myocardial infarctions in the experimental group versus 16 cardiac deaths and 17 nonfatal myocardial infarctions in the control group (de Lorgeril et al., 1994). It is interesting to note that the patients on the Mediterranean type of diet had increases in ~blood levels of vitamin E and C while controls did not.
Garlic, a staple of the Mediterranean diet, also has been implicated as a major disease-preventive food. A growing number of reports in the medical literature suggest that garlic supplementation may be effective in decreasing serum cholesterol levels by as much as 15 to 20 percent and thus may have a protective effect against cardiovascular disease (Kleijnen et al., 1989; Turner, 1990). Many of these studies have been faulted for having methodological problems, although a recent meta-analysis of the various studies reporting a cholesterol-lowering effect found that garlic did appear to significantly reduce total serum cholesterol (Silagy and Neil, 1994).
There are also reports suggesting that garlic may prevent the development of cancer in humans (Dorant et al., 1993). Lin and colleagues (1994) reported that processed garlic effectively reduced the amount of DNA damage caused by N-nitroso compounds, which are found in many foods such as cooked meat and have been implicated as carcinogens (cancer-causing compounds).~Traditional Native American Indian diet. In the case of the Hopi and Papago tribes, studies have shown that traditional foods have mineral content superior to federally provided commodity foods (Calloway et al., 1974). Followers of traditional Native American diets have found ways of maximizing available nutrients; an example is in the techniques of processing the corn used in tortillas, a staple in diets derived from the Mexican and Central American tradition. The corn is soaked in lime, which softens the skin of the corn kernels as well as increasing the calcium content of the resulting tortillas (Katz, 1987). Traditional lime soaking also liberates bound niacin in the corn. Because milled corn has been substituted for lime-soaked corn in Native American Indian diets, niacin deficiency has become a problem, and incidences of niacin-deficiency-induced pellagra have increased. Although few studies have been done on the possible disease-preventive aspects of the traditional Native American Indian diet, health surveys have found that heart disease and cancer, two diet-related diseases, are virtually nonexistent in some Indian populations, such as the Navajo (Reese, 1972).