Greek column rather than Egyptian pyramid

The Mediterranean food guide: Greek column rather than Egyptian pyramid

Artemis P. Simopoulos

The nutritional requirements of contemporary humans were almost certainly established over eons of evolutionary experience and the best evidence indicates that this evolution occurred on a dietary intake that was low in saturated fat and sodium, and higher in protein, cholesterol, antioxidant vitamins, and calcium than the current diet (Table 1).(1)(2) There are major differences between Paleolithic nutrition and current Western diets in types of fats and oils (Fig. 1).(3) The fat content of Paleolithic nutrition was lower than that of today’s Western diet; it was lower in saturated fats, lower in omega-6 fatty acids, and higher in omega-3 fatty acids, and contained minimal amounts of trans fatty acids, since they occur rarely and in small amounts in nature.(4) It is estimated that trans fatty acids comprise between 5% and 15% of energy available in Canadian and U.S. diets because of hydrogenation of vegetable oils.(5) Trans fatty acids have many adverse effects (Table 2).(2)

[ILLUSTRATION OMITTED]

Table 1 Comparison of the Late Paleolithic Diet(a) and the Current

American Diet

Current

Late Paleolithic diet(a) American diet

Total dietary energy (%)

Protein 34 12

Carbohydrate 45 46

Fat 21 42

P:S ratio(b) 1.41 0.44

Cholesterol (mg) 591 600

Fiber (g) 45.7 19.7

Sodium (mg) 690 2300–6900

Calcium (mg) 1580 740(c)

Ascorbic acid (mg) 392.3 87.7(c)

(a)Assuming the diet contained 35% meat and 65% vegetables.

(b)P:S, polyunsaturated:saturated fats.

(c)U.S. Department of Agriculture Food consumption Survey, 1977–1978. Adapted from Ref. 1.

Table 2 Adverse Effects of Trans Fatty Acids

Increase

Low-density lipoprotein (LDL)

Platelet aggregation

Lipoprotein (a) [Lp (a)]

Body weight

Cholesterol transfer protein (CTP)

Abnormal morphology of sperm

(in male rats)

Decrease or inhibit

Decrease or inhibit incorporation of

other fatty acids into cell

membranes

Decrease high-density lipoprotein

(HDL)

Inhibit delta-6 desaturase (interfere

with elongation and desaturation of

essential fatty acids)

Decrease serum testosterone (in male

rats)

Cross the placenta and decrease birth

weight (in humans)

From Ref. 2.

Although living conditions have changed to an almost inconceivable degree since the emergence of agriculture 10,000 years ago, there appears to have been little, if any, fundamental alteration in the genetic constitution of humanity over the same period.(6) Therefore, the exercise and dietary patterns of humans living during the Paleolithic period can be considered natural paradigms for health and prevention of cardiovascular disease, hypertension, diabetes, osteoporosis, arthritis, and some forms of cancer.

Since World War II, the Mediterranean diet, as a model of healthful diet, has been the subject of many studies.(7)(8) However, many uncertainties exist concerning the nutritional characteristics of this type of diet. The research study carried out by the European Atomic Energy Community (EURATOM) in the 1960s represents one of the major sources of information on the quality and quantity of food intake in Europe.(9) The study showed remarkable dissimilarities among the different countries studied. It is clear that the Mediterranean diet is not a homogenous nutritional model. There are several Mediterranean nations with varied cultures, traditions, and dietary habits. This is illustrated by the variation noted in per capita annual consumption of dairy products. Table 3 shows that, in 1986, Greece produced and consumed less milk than France, Italy, Spain, and Yugoslavia–60 L compared with 80 to 115 L of milk, while it consumed more cheese, 22.2 kg/capita/year (Table 4).(10) Table 4 also shows that butter consumption in all Mediterranean countries, except France and Italy (whose intakes were 7.5 and 2.2 kg, respectively), is less that 1 kg/capita/year. In general, the Greeks eat more cheese and less butter and drink less milk than do the French or Italians.(10) Therefore, it would not seem correct to extrapolate from the eating habits either in Greece or Southern Italy to all the other Mediterranean countries. However, beyond the apparent differences, some nutritional characteristics are common to all or most of the Mediterranean area. The results of the EURATOM study seem to demonstrate that the Mediterranean diet is characterized by being:

(1) low in saturated fat and high in monounsaturates (olive oil)

(2) low in animal protein

(3) rich in carbohydrates

(4) rich in vegetables and leguminous fiber.

Table 3 Milk Production, in Thousands of Tons, in Five Mediterranean

Countries in 1986

Source

Sheep Goat Cow Totals

Greece 600 400 642 1,642

Yugoslavia 140 ND 4,600 4,740

Spain 232 360 6,702 7,394

Italy 483 119 10,270 10,772

France 1,087 454 33,700 35,241

ND, no data.

Modified from Ref. 10.

Table 4 Per-Capita Annual Consumption of Dairy Products in Seven

Mediterranean Countries

Product 1966 1986

Greece Liquid milk ND 54.0 L

Fermented milk ND 6.0 L

Butter ND 0.9 kg

Cheese ND 22.2 kg

France Liquid milk 103.0 L 79.7 L

Fermented milk 4.2 L 13.0 L

Butter 9.0 kg 7.5 kg

Cheese 12.1 kg 21.1 kg

Israel Liquid milk 60.0 L 72.5 L

Fermented milk 8.0 L 16.8 L

Butter 1.2 kg 0.7 kg

Cheese 8.8 kg 15.4 kg

Italy Liquid milk 66.8 L 78.0 L

Fermented milk 0.5 L 3.2 L

Butter 1.6 kg 2.2 kg

Cheese 9.1 kg 17.3 kg

Yugoslavia Liquid milk ND 100.7 L

Fermented milk ND ND

Butter ND 0.5 kg

Cheese ND 17.0 kg

Malta Liquid milk ND 53.3 L

Fermented milk ND ND

Butter ND 0.7 kg

Cheese ND 7.6 kg

Spain Liquid milk 71.0 L 108.1 L

Fermented milk 1.2 L 6.9 L

Butter 0.3 kg 0.5 kg

Cheese 2.1 kg 5.1 kg

ND, no data; L, liter.

Modified from Ref. 10.

Twenty years later, Giacco and Riccardi(11) reported on their study based on 1979–1981 Food Balance Sheets published by the Food and Agriculture Organization of the United Nations (FAO)(12) on the dietary intake of 14 Mediterranean countries (Portugal, Spain, France, Italy, Yugoslavia, Greece, Malta, Israel, Libya, Algeria, Tunisia, Turkey, Egypt, and Morocco) and compared to the diet of the United States for the same period. They found a common nutritional profile for the Mediterranean countries characterized again by a low intake of saturated fat, moderate intake of total fat with prevalence of monounsaturated fat (olive oil), and high intake of complex carbohydrates. Contrary to their expectations, the daily intake of fiber, which is known to have beneficial effects on glucose and lipid metabolism and also to contribute to cancer prevention, was lower than the recommended intake of 20 g/1000 kcal/day in the whole Mediterranean area.

THE GREEK DIET

Table 5 compares the dietary characteristics in the population of the United States and Greece before 1960.(13) The percentage of energy from dietary fat is 39% for the United States and 37% for Greece, but the saturated fat intake is 18% and 8%, respectively. Greeks ate more fish, legumes, vegetables, fruits, and cereals; drank more alcohol (wine); and ate less meat and fewer eggs than the U.S. population. Because the life expectancy at age 45 was higher in Greece than in the United States and coronary heart disease and total cancers were less prevalent in Greece than in the United States, (Table 6),(13) the Greek diet was considered optimal, although other factors besides diet, such as genetics, environmental pollutants and sunlight also differ between the two countries. Nonetheless we can agree that diet is an important factor that could account to a significant extent for the differences in health statistics between the populations of the United States and Greece.

Table 5 Dietary Characteristics in the United States and Greece in the

1960s

Dietary characteristics U.S. Greece

Fat (% energy) 39 37

Saturated fat (% energy) 18 8

Vegetables (g/day) 171 191

Fruits (g/day) 233 463

Legumes (g/day) 1 30

Breads and cereals (g/day) 123 453

Potatoes (g/day) 124 170

Meat and poultry (g/day) 273 35

Fish (g/day) 3 39

Eggs (g/day) 40 15

Alcohol (g/day) 6 23

Dietary information is from References 7 and 8. The means of data from Crete and Corfu have been averaged for Greece. Since 1960, consumption of red meat and animal fat has greatly increased in Greece.

Modified from Ref. 13.

Table 6 Life Expectancy and Disease Rates in the United States and Greece

in the 1960s

Life expectancy and disease

rates Gender U.S. Greece

Life expectancy at age 45 (yr) M 27 31

F 33 34

Coronary heart disease M 189 33

F 54 14

Cerebrovascular diseases M 30 26

F 24 23

Breast cancer F 22 8

Stomach cancer M 6 10

F 3 6

Colorectal cancer M 11 3

F 10 3

Total cancers M 102 83

F 87 61

Standardized mortality rates are per 100,000 people, age 0 to 64. For males (M) and females (F), life expectancies at age 45 in 1989 to 1991 were 32.4 and 36.5 years, respectively, for Greece, and 30.8 and 36.1 years, respectively, for the United States.

Modified from ref. 13.

A major difference between the diet of the United States and Greece is in the type of fats. Not only is the Greek diet lower in saturated fat, but it is high in monounsaturates, specifically olive oil, whereas in the United States the diet is high in polyunsaturated fatty acids from vegetable oils that are rich in omega-6 fatty acids, known to lead to tumors in animals and to increased platelet aggregation in humans.(4) Because the U.S. diet is low in omega-3 fatty acids, there is an imbalance between the omega-3 and omega-6 fatty acids, which leads to a proinflammatory and prothrombotic state.(4) The U.S. diet is also high in trans fatty acids, up to 5% to 15% of energy available in the food supply. Trans fatty acids, the result of the hydrogenation process, are found in margarines, salad dressings, and frying oils and produce a number of adverse effects (Table 2) that are associated with increased rates of coronary heart disease and hypertension.

DIETARY GUIDELINES AND FOOD GUIDES AROUND THE WORLD

Over the past 20 years, many countries have developed dietary guidelines that have a common theme. These guidelines recommend to limit fat, saturated fat, and cholesterol; limit salt and sugar; and increase fresh fruits and vegetables while maintaining desirable body weight. Recently, in the United States, the food guide pyramid was developed by the U.S. Department of Agriculture (USDA) based on a series of studies the USDA considered essential for translating the recommendations of nutrient intake into recommendations of food intake (Fig. 2).(14) Ideally, a food guide is based on:

* Data of food composition

* Food intake of the population

* Food availability

* The prevalence in the population of diseases with nutritional components

* The prevalence of genetic diseases, and gene frequency.

[ILLUSTRATION OMITTED]

Therefore, one would expect that food guides would be different in various parts of the world and one would expect to see different food guides, for example, for the population of Finland versus the population of Japan. Other countries have already developed their own food guides. In Mexico (Fig. 3),(15) the Mayan pyramid is based on fruits, vegetables, and whole grains, consistent with that population’s traditional diet. So far, only the USDA food guide pyramid is based on grains.

[ILLUSTRATION OMITTED]

In developing the U.S. food guide pyramid, scientific considerations were preempted by political and economic factors.(13) Therefore, instead of changes needed in the food supply to improve overall health, the public instead was asked to decrease the intake of fats and oils and to increase grains, fruits, and vegetables as a way of decreasing omega-6 and trans fatty acid intake. Grains form the base of the U.S. pyramid, yet grains are newcomers into our diet, based on the evolutionary aspects of diet from anthropology and archaeology and studies on hunter-gatherer and primitive populations existing today.(1)(2) Grains assumed an important part of our diet originally 10,000 years ago, at the time of the agricultural revolution.

FATS AND OILS

The U.S. food guide pyramid has been criticized for not distinguishing among the various fatty acids, such as trans fatty acids and omega-6 and omega-3 polyunsaturated fatty acids, and for not emphasizing the beneficial effects of olive oil in raising high-density–lipoprotein (HDL) and in preventing the oxidation of low-density–lipoprotein (LDL) cholesterol. A low-fat diet has been shown to lead to essential fatty acid deficiency in 5% to 25% of the Framingham Study population.(16) Furthermore, a high carbohydrate diet leads to hypertriglyceridemia, especially in middle-aged women and in those men and women who already have hypertriglyceridemia. Also, the recommendation of two to three servings of meat a day may be unhealthy, because red meat has been shown to be associated with cancer of the colon and prostate in epidemiologic studies.(17)(18)

OLIVE OIL

The backbone of the Mediterranean diet is olive oil, because it provides a larger number of calories than any other single food. Greece, along with Italy, Spain, and Portugal are the major producers of olive oil. Greek olive oil is aromatic and high in oleic acid (80%) and contains about 6% to 16% omega-6 fatty acids and 0.3% to 1.3% omega-3 fatty acids. This composition of fatty acids places olive oil in a unique and superior position of all other oils when it comes to both taste and health:

* Olive oil, like all nonanimal fats, does not contain cholesterol and reduces LDL oxidation.(19) In addition to vitamin E, a known antioxidant, olive oil contains 3,4-dihydroxy-phenyl ethanol as one of several phenolic antioxidants with antithrombotic effects in vitro.(20)

* Unlike tropical oils, olive oil is very low in saturated fats.

* Olive oil does not raise LDL, but it does raise HDL (the good cholesterol), whereas vegetable oils such as corn oil lower both LDL and HDL.

* An olive oil diet replaces omega-6 in phospholipids, cholesterol esters, and triglycerides in the serum. In serum phospholipids, the decrease of linoleic acid induced by increased oleic acid with the olive oil diet is associated with an increase of gamma-linolenic and dihomo-gamma-linolenic acids, without any modification of arachidonic acid. These findings indicate a stimulation of delta-6 desatu-rase and subsequent elongation, without acting on delta-5 desaturation. An increase in omega-3 fatty acids is also observed in serum but not in red blood cell phospholipids after oleic acid or olive oil ingestion.

* In cultured fibroblasts obtained after an olive oil diet, olive oil ([.sup.3H]) cholesterol efflux was highest in the fraction of HDL.(3)

* Oleic acid found in olive oil increases the incorporation of omega-3 fatty acids in the cell membranes and decreases the oxidation of LDL. Therefore, increasing oleic acid by eating more olive oil could reduce the atherogenic potential of LDL in addition to lowering LDL levels.

* Squalene is a substance that is found in higher amounts in olive oil (136 to 708 mg/100 g olive oil) that has a number of beneficial effects. In animal experiments, squalene combines easily with oxygen ions, emitting molecular oxygen, especially in tissues short of oxygen, and is very active and effective in the rehabilitation of scars, increasing heart activity, expansion of blood vessels, and inhibition of atherosclerosis.

* Olive oil is indeed a nutritionally desirable food and there is no scientific reason to restrict its use. In addition to its health benefits olive oil is known for its appealing golden emerald color and its aroma and taste.

FRUITS AND VEGETABLES (VITAMINS E, C, BETA-CAROTENE, CALCIUM, FOLATE, AND

FIBER)

The beneficial effects of fruits and vegetables may be related to their content of antioxidant vitamins and calcium and fiber. In the 1970s, fiber was considered the major factor in fruits and vegetables responsible for the prevention of cancer. More recently, the emphasis has been on vitamins E, C, and beta-carotene (for their antioxidant properties) and folate. For example, studies on purslane (a prehistoric plant) show that, in addition to being high in vitamins E, C, and beta-carotene, it is also high in glutathione.(21)(22) As research advances, other plant components (especially phenolic compounds) are certain to be discovered that are beneficial to health.

An important step in atherogenesis is the oxidation of LDL.(23) Antioxidants such as vitamin E have been shown to inhibit the oxidative modification of LDL. Supplementation with vitamin E, about 100 mg/day, lowered by about 40% the risk of myocardial infarction compared with those in the lower-in-take group in two prospective studies involving men and women. Among European countries, those with higher blood antioxidant levels had lower rates of coronary heart disease.(24) Eating higher amounts of fruits and vegetables or having higher blood levels of carotenoids has been shown in epidemiologic studies to reduce the potential to develop various cancers.(25)(26) An inverse association with vegetable and fruit intake has been noted for cancers of the oral cavity, larynx, pancreas, bladder, and cervix.(25)(26) The association is stronger for an inverse association between vegetable and fruit intake and lung cancer,(25)(26)(27) which has led to the suggestion that the protective factors might be beta-carotene.(28) In many case-control studies, intake of fruits and vegetables is related to lower risk of cancer of the stomach.(25)(26) A protective role of vitamin C is suggested. Similarly, there is a lower risk for cancer of the colon with increased consumption of fruits and vegetables.(29) Fiber is considered a protective factor here, but recent evidence suggests folic acid could account for the reduced risk.(30)

CALCIUM

Wild plants are rich sources of calcium. Evidence from Paleolithic nutrition suggests that our ancestors had calcium intakes in the range of 2000 mg/day or more.(31) High calcium intake influences bone mass development. An adequate bone mass is essential during adolescence and young adulthood in the prevention of osteoporosis. Calcium is also important in the control of blood pressure(32) and in decreasing the risk of colon cancer. Sardines, vegetables, and cheese (dairy products and milk) that are part of the Mediterranean diet are all excellent sources of calcium.

RECOMMENDATION FOR THE DEVELOPMENT OF A MEDITERRANEAN FOOD GUIDE

The major changes that are occurring in the food supply of various populations as the Western diet is being adopted have led to a number of investigations in many indigenous populations, i.e., the native Hawaiians, Australian aborigines, American Indians, and others.(33) The indigenous diets differ from the Western diet in types of fats, fiber, antioxidant content, potassium, and protein. Adoption of a Western type of diet and life-style has led to increases in obesity, diabetes, and cardiovascular diseases in these populations. When returned to their indigenous diets and lifestyles, individuals experience decreases in body weight, blood pressure, and diabetes. All these indigenous diets are low in saturated fat; high in essential fatty acids, with plenty of fruits and vegetables; higher in potassium but lower in sodium; and high in antioxidants; with adequate amounts of protein provided by fresh fish, lean meat, eggs, yogurt, and other forms of fermented milk.

I have attempted to develop a Mediterranean food guide based on information of Paleolithic nutrition and the dietary habits of the people in the Mediterranean region before 1960, i.e., before the onslaught of Western dietary products. Instead of the pyramid, which represents the pharaohs’ tomb or a Mayan temple, I have selected a Greek column for the Mediterranean food guide. The concept of the “pyramid” is based on a high-carbohydrate/low-fat diet without any distinction made about the various fatty acids, while promoting grains rather than fruits and vegetables. The concept of the food guide in the form of a Greek column is based on genetic variation and nutrition–it is consistent with the fact that not everybody is susceptible to chronic diseases to the same extent–and on a balanced energy intake and energy expenditure.(34)(35) It is not a low-fat/high-carbohydrate diet, since olive oil is the cooking oil and constitutes a higher source of energy than any other food. The Mediterranean food guide excludes vegetable oils and hydrogenated oils and their products. The Greek column is based on foods and not on food groups, and although it excludes certain foods it does not limit the intake of naturally occurring foods nor insist on the inclusion of large numbers of portions. At this point, the Greek column is theoretical, but it could be pilot-tested in a sample of the population today. Because it is based on human evolution and on traditional Mediterranean diets, it should be safe and should lead to further studies on information of the composition of the indigenous food supply in the region.

In essence, such a guide would be similar to the food the people of the Mediterranean region ate before 1960, with perhaps more fish and poultry. Based on the information to date, I propose the following. A food guide should be based on a set of principles taking into account genetic predisposition and energy expenditure (Fig. 4): (1) moderation, (2) variety, (3) proportionality, and (4) energy intake = energy expenditure. This set of principles forms the base from which a Greek column springs up. The first part of the Greek column contains the foods to be added to any meal: olive oil, lemon, vinegar; olives; bread; cheese; yogurt; fruits, fruit juices; nuts, garlic, onions; vegetables, herbs, spices; pasta, rice, potatoes; and water and wine. Above that is the basic components of daily meals with emphasis on legumes, fish, and poultry. Meat and eggs, as such, comprise a main meal once a week each. The foods to be added to any meal are rich in antioxidant vitamins and minerals and have a balance of omega-6 and omega-3 fatty acids with the addition of olive oil and herbs daily, and fish three times per week. Because olive oil is an absolutely safe oil, there is no limit to how much is ingested as long as energy intake equals energy expenditure. The same consideration is given to all other food items. Margarines rich in trans fatty acids, and vegetable oils and other artificial foods are not included in the Greek column. Sweets should be eaten rarely or on special occasions, and the same is true for soft drinks and hard liquor.

[ILLUSTRATION OMITTED]

CONCLUSION

Based on the scientific information on the role of foods and certain nutrients in the development of chronic diseases such as coronary heart disease, hypertension, cancer, obesity, osteoporosis, and the most recent evidence that folate deficiency may account for 50% of neural tube defects and that dietary antioxidants vitamin E, vitamin C, and carotenoids are inversely associated with cataracts, it is essential that each country or region develop a food guide for its population. Instead of a pyramid, which symbolizes a tomb for Egyptian pharaohs, or a Mayan temple, I propose that we consider, for the Mediterranean region, the concept of the Greek column (Fig. 4).

Recent advances show that major adverse components in Western diets are the increase in vegetable oils rich in omega-6 fatty acids and the decrease in omega-3 fatty acids, and the increase in trans fatty acids in the form of margarines, shortening, and frying oils. Trans fatty acids in the diet in large amounts is a new phenomenon. Trans fatty acids entered the food supply shortly after World War I and reached high proportions, comprising between 5% and 15% of energy available in the Canadian and U.S. diet today. Although promoted as a substitute for butter, trans fatty acids are twice as likely to increase the ratio of total cholesterol:HDL cholesterol, because they increase LDL cholesterol while lowering HDL cholesterol, and have many other adverse effects that may contribute to obesity, hypertension, and diabetes (Table 2). The emphasis in the U.S. pyramid on cereals, bread, pasta, etc., which are processed grain products rather that whole grains, as the major source of energy, leads to a lesser intake in fruits and vegetables despite the recommendation to increase their intake.

Each country or region needs to develop its own nutritional goals and food guides. In developing nutritional goals, data on the dietary and health status of the population must be considered. Knowledge of the food composition consumed by a population is essential, which requires commitment on the part of governments and industry to develop accurate food composition tables. Even in the United States, accurate food composition tables do not exist, as shown by the General Accounting Office (GAO) report, “Better Guidance Needed to Improve Reliability of USDA’s Food Composition Data.”(36)

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