Whole Foods, Fruits and Vegetables Preferred as Source of Phytochemicals
WILMINGTON, DE ? Scientists believe that consuming a diet rich in fruits, vegetables, and other whole foods is a preferred way to protect against disease. Such a diet provides an abundance of health-protective substances, called phytochemicals. These plant chemicals, together with other nutrients and dietary fiber, may slow the aging process and reduce the risk of many chronic diseases, including cancer, heart disease, stroke, high blood pressure, cataracts, osteoporosis, and urinary tract infections.
An increasing number of people are consuming phytochemicals for optimal health. Some people prefer the disease-fighting power of whole, plant-based foods, while others turn to dietary supplements to provide specific, individual food components. As a part of Produce for Better Health?s ?Nature?s Functional Foods: Arey They Here?? Symposium, a group of distinguished researchers recently addressed the issue of whole foods versus individual components.
?One of the most powerful sources of disease prevention comes from eating whole plant-based foods,? said Elizabeth Pivonka, President of the Produce for Better Health Foundation. ?Fruits, vegetables and nuts contain a variety of phytochemicals and other nutrients which work together to help prevent disease. In contrast, a supplement contains only one or a few phytochemicals, which if consumed in excess could actually cause harm. The truth is that the whole is greater than the parts. Everyone wants a magic bullet, but, in the end, it all points back to the whole plant food, which has far more to offer than any supplement.?
Pivonka said that the lines between foods, functional foods, nutraceuticals, medicinal foods and supplements are blurred. (See Figure 1 below.) For example, it may be difficult to distinguish when a food is functional and when it is medicinal. ?Consumers can overmedicate when taking herbs or dietary supplements. They often are not aware of the dangers of self-medication. We don?t know all the drug-nutrient interactions with supplements, especially in high doses.? Researchers do not know the risk/benefit on high doses of phytochemicals at this time. ?Because herbal products can act like drugs, physicians today recommend to their patients that they refrain from herbal products for a month prior to surgery because of their potential interaction with anesthetics,? Pivonka said.
Figure 1
???? Foods???? Functional???? Nutraceuticals????????Medicinal????Supplements
???????????? Foods???????????????? Foods
Scientists have identified thousands of phytochemicals, although only a small number appear to be active in humans. Identifying the most promising of these has been a major focus of researchers for the past 15 years. During this time, research has been the most prolific in the area of cancer, followed by cardiovascular work.
?Overall dietary patterns, rather than specific individual components, are most strongly linked to reduced cancer risk,? continued Johanna Lampe, Ph.D., R.D. with the Fred Hutchinson Cancer Research Center in Seattle, Washington. Lampe pointed out that it is important to eat plant foods over supplements for three reasons: 1) Many phytochemicals and other compounds in whole foods have yet to be identified. 2) The effects of phytochemicals in the body may be different when they are consumed as part of a plant from the effects seen when they are removed from the food. Absorption, for example, may be altered. 3) There may be a negative effect when a large dose of a single compound is ingested. ?In studying minerals, for example, we know that mineral imbalances can occur, such as the depression of iron absorption when zinc levels are high. So, it is highly likely that similar imbalances could occur with phytochemicals,? explained Lampe.
Dr. Lampe added that there are a number of factors that may explain the individual differences in response to phytochemicals. The colonic microflora population probably differs from individual to individual, depending on the person?s habitual diet, medications, and possibly gender differences in colonic transit. There may be genetic differences in the metabolism of phytochemicals, which would lead to gene/diet interactions. The time or age a person is exposed to a phytochemical may be also a factor. For example, being exposed to a specific phytochemical in utero or through pre-puberty may be of critical importance. Additionally, the regular consumption of a phytochemical versus intermittent exposure to the protective components may be an important factor. Much more research is needed in these areas.
????The role of phytochemicals in plants may shed some light on their possible role in humans. Plants use the naturally occurring phytochemicals to protect themselves from predators, excessive UV radiation, and the elements. ?These same defenses may be what are protective to humans against disease states,? explained Dr. Amy Howell, Ph.D. from the Blueberry Cranberry Research & Extension Center at Rutgers, the State University of New Jersey. Their mechanisms of action may be their oxidative effects, the prevention of cell proliferation that occurs in cancer, the detoxification of enzymes, the stimulation of the immune system, or the regulation of hormones.
?Consumers often think that the bioactive phytochemicals in supplements and herbal products are safer than pharmaceuticals, but consumers forget that many of the medicines on the market today were derived from plant-based foods.? Dr. Howell said. He cautioned that the bioactive molecules in dietary supplements and herbal products are not always known, the recommended dosage is often arbitrary, high concentrations of heavy metals often result from the way they are dried, and the possibility of drug interactions is something that should not be overlooked. For example, the Food and Drug Administration (FDA) has just issued a notice about St. John?s Wort?s ability to decrease blood levels of a drug used to treat HIV infection.
????Dr. Howell went on to explain that the bioactivity of a plant phytochemical might be lost during processing into an herbal product or supplement. Additionally, the oxidation that occurs during storage may also affect its bioactivity. Compounds may require synergistic effects with other food components before they are beneficial. For example, we now know that iron and vitamin C have a synergistic relationship and that iron is better absorbed in the presence of vitamin C. Similar synergistic relationships are likely with phytochemicals.
?In some cases, there is evidence to suggest that when plant chemicals are isolated from a food source, they lose some or all of their health functionality because they are missing certain synergistic cofactors or experience excessive oxidation during the extraction process. On the other hand, if whole functional foods are eaten, people will get the maximum benefit with less chance of toxicity. By eating whole fruits and vegetables,? explained Dr. Howell, ?one gets the phytochemicals in a form that can provide maximum health benefit. The active compounds are in a more stable form and the naturally present synergistic compounds may increase the desired effect, or absorption, of the phytochemicals. Additionally, a person is less likely to ingest toxic dosages of a bioactive compound when it is consumed in a food alone. Another benefit of eating whole foods is that they are usually less expensive than supplements.?
?While individual nutrients and phytochemicals have an important place in nutrition and health and need to be studied in isolation, the foundation of a healthful diet has to be whole foods with all their knowns and unknowns,? stated Dr. Gene Spiller, Ph.D., a symposium presenter with Health Research and Studies Center, Inc. in Los Altos, California. Dr. Spiller used nuts, such as almonds and walnuts, as examples of the complexity and benefits of eating whole foods with a specific focus on heart disease. He presented studies where nuts, fresh and dried fruits, fresh vegetables, whole grains, and beans where studied. Dr. Spiller and other researchers have shown that altering the ratio of monounsaturated fats to saturated fats in a person?s diet could lower both total and low-density lipoprotein (LDL) cholesterol.
More research, including epidemiological, laboratory, and clinical trials, is needed in the area of phytochemicals. Caution must be exercised until further knowledge is obtained in this area. Population studies often give scientists a ?big picture? clue to a possible relationship between a food element and a disease, but they do not prove a cause-and-effect relationship. These must be followed with laboratory and clinical trials to further explore a diet-disease relationship. In the case of beta-carotene, for example, population studies suggested that beta-carotene may offer protection against lung cancer. These population studies were followed by clinical trials. A team of Finnish researchers studied 29,000 smokers. To their dismay, lung cancer actually increased among the men taking beta-carotene supplements. One possible explanation for the unexpected results was that the participants took synthetic beta-carotene supplements, which is different from eating a carotenoid-rich diet.
The study of phytochemicals as they pertain to human health is a new field. Before any definitive recommendations can be made as to intake of specific types and amounts of phytochemicals, researchers must complete more studies. The picture is far from complete. Most scientists agree it is likely that the synergistic effects of phytochemicals as they coexist naturally with other phytochemicals and nutrients is what gives them their unique properties. Foods are likely to contain many additional beneficial compounds that have not yet been identified.
There is overwhelming agreement that the best way to obtain potential benefits of phytochemicals is by eating a wide variety of plant foods. Only by eating whole fruits, vegetables, nuts, soy, and whole grains can a consumer benefit from the many interactions that take place between these phytochemicals and nutrients. Researchers conclude that food, not dietary supplements, should be consumed as the primary line of defense for a variety of reasons.
The Produce for Better Health Foundation is a not-for-profit educational foundation which co-sponsors the national 5 A Day for Better Health program, along with the National Cancer Institute. Since 1991, the Foundation has encouraged Americans to eat 5 or more daily servings of fruits and vegetables to improve their health.
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Tips for Getting the Most Benefit From the Phytochemicals in Your Food
1. Eat raw fruits and vegetables. While many phytochemicals are fairly stable, some are not stable to heat and oxygen. The greatest amount of phytochemicals will probably be found in raw, unprepared fresh foods.
2. Buy fruits and vegetables more often. Buy fresh produce a couple of times a week, if possible. Instead of storing your fruits and vegetables for several days or weeks in the refrigerator or on a kitchen counter where they are exposed to air, try buying produce more often and using it within a couple of days after purchase.
3. Get at least 5 A Day. Be sure to eat at least 5 servings of fruits and vegetables every day. People, especially men, consuming 2500 calories a day or more should eat 9 servings of fruits and vegetables a day for optimal health and phytochemical protection.
4. Eat a wide variety of whole foods. More than 2000 phytochemicals have been identified. Be sure to include food items on the right from each of the categories given below:
Phytochemical Component????Examples of Fruits, Vegetables and Whole Foods
Allyl Sulfides????onions, garlic and allium family
Indoles
Isothiocyanates????cruciferous vegetables (broccoli, brussel sprouts, cabbage, turnip, and
kale family)
Flavonoids????berries, grapes, apples, artichokes, cranberries, eggplant, legumes, green tea & red wine
Carotenoids????dark yellow and orange fruits, deep green vegetables, and tomato products
Isoflavones????Soy products
Phenolic Acids????Found to some degree in almost all fruits and vegetables; wine
Phytosterols????Almonds, cashews, peanuts, sesame & sunflower seeds, whole wheat, corn, and soybeans
Saponins????Found in most vegetables and herbs, but especially abundant in soybeans and other legumes, oats, peas, potatoes, and spinach.
5. Add color to your life. Phytochemicals are the pigments that give fruits and vegetables their color. Generally, the more color the more phytochemicals present. Select fruits and vegetables that are rich in color, whether they are red, orange or deep green.
6. Don?t forget the leaves, seeds and peel. The leaves, seeds, and peel of many vegetables and fruits are a rich source of many phytochemicals. Try adding leafy green vegetables to soups, casseroles and stir-frys. Use the grated peel of fresh citrus in baking. Sprinkle sesame or sunflower seeds on top of steamed vegetables or mixed green salads. Limit peeling of fruits and vegetables when possible, as many phytochemicals are concentrated in the skin. Scrub or wash gently with running water all produce prior to eating.
7. Be Adventurous. There are many new and different fruits and vegetables available in today?s supermarkets. Visit the exotic produce section of your supermarket. Add one new fruit or vegetable to your shopping cart each week. Or, visit an oriental food store and pick up a new vegetable to try.
8. Buy a new cookbook or take a class. There is no end to the number of ways to prepare fruits and vegetables. Order a copy of The Phytopia Cookbook, A World of Plant-Centered Cuisine (see order information on a separate sheet) or take a cooking class offered by your community college. These are great ways to find and try new recipes.
Functional Foods- ????Diet supplements that are similar in appearance to conventional foods and are consumed as part of a normal diet. They deliver one or more active ingredients (that have physiological effects and perhaps enhance health) within the matrix of a food.
Nutraceutical- ????Diet supplements that deliver a concentrated form of a presumed bioactive agent from a food, presented in a nonfood matrix, and used to enhance health in dosages that exceed those that could be obtained by normal foods.
Phytochemical- ????A phytochemical is a natural plant substance that works with nutrients and dietary fiber to protect against disease. Research suggests that phytochemicals working together and with other nutrients found in fruits, vegetables, and nuts may help slow the aging process and reduce the risk of many diseases, including cancer, heart disease, stroke, high blood pressure, cataracts, and urinary tract infections.
Antioxidant-????Antioxidants fight free radicals by neutralizing them and preventing cell oxidation. Free radicals can react with and damage unsaturated fatty acids, proteins, and DNA. It is thought that free radical damage contributes to heart disease, aging, hardening of the arteries, cancer, arthritis, cataracts, and other health problems. Fortunately, this destructiveness can often be reversed or prevented with the antioxidants found in fruits and vegetables, such as vitamins A, C, and E, selenium, and anthocyanins, a phytochemical which gives berries their rich color.
Dietary
Supplements-????Ingredients extracted from foods, herbs, and plants that are taken without further modification outside of foods for their presumed health-enhancing benefits. A supplement is something that completes or makes an addition.
Biotechnology-????The use of biotechnical methods to modify the genetic material of living cells so they will produce new substances or perform new functions. Examples include recombinant DNA technology, (in which a copy of a piece of DNA containing one or a few genes is transferred between organisms or recombined within an organism) or gene splicing (which may be likened to cutting a circle of tape and inserting a different piece, and rejoining both ends to the new piece).
Bioengineering- ????The application of engineering principles to the fields of biology and medicine. Advances in bioengineering allow the development of plants with higher levels of desirable nutrients and phytochemicals.
Designer Foods-????Designer foods are processed foods that are supplemented with food ingredients naturally rich in disease-preventing substances. This may involve genetic engineering of foods.
Pharmafoods-???????????? Foods or nutrients that claim medical or health benefits, including the prevention and
treatment of disease.
Table 1. Phytochemicals: The Cost of the Natural Foods vs. the Supplements
Nutrient /????????Amount of????Approx.????Dietary????Amount of????Suggested????
Phytochemical????Food Source????Phytochemical*????Cost????Supplement????Phytochemical**????Dose on Bottle????Cost
lycopene????tomato paste
2 tablespoons????2,167 ug.????$ .11/svg.????lycopene tablets????15,000 ug.????2-3 tablets/ day????$ .50/tablet or
$ 1.50 for 3
beta-carotene????carrot
1 medium????56,880 IU????$ .13/each????beta-carotene tablets????20,000 IU????2 tablets/ day????$ .37/tablet or
$ .74 for 2
isoflavones????tofu
1? slice, 3 oz.????40 mg.????$ 0.35/svg.????isoflavone capsule????12 mg.????1 capsule/day????$ .13/capsule
aliin????garlic
1 clove????30,000 ug.????$ .04/clove????garlic tablets????1,300 ug.????2 tablets/day????$ .18/tablet or $ .36 for 2
sulforaphane????broccoli
1/2 cup raw????4,400 ug.????$ .12/svg.????Broccoli in a capsule????100 ug.????1-2 capsules
/day????$ .22/capsuleor $ .44 for 2
Note: The exact amount of phytochemicals found in fruits and vegetables is not currently known. New research is underway through the efforts of Produce for Better Health Foundation and the United States Department of Agriculture to develop a database that identifies the quantities of 25 disease-fighting phytochemicals found in a variety of fruits, vegetables and nuts. They hope to share this information in fall, 2001.
** Note: The amount of phytochemical listed on a dietary supplement label may not reflect the actual amount present.
Phytopia Cookbook Offer
Produce for Better Health Foundation is pleased to offer The Phytopia Cookbook, A World of Plant-Centered Cuisine. Written by Barbara Gollman, a chef-trained registered dietitian and former medical microbiologist, and Kim Pierce, an award-winning Dallas Morning News food journalist with a love of cooking, this cookbook offers a wide array of recipes designed around fruits, vegetables, and other whole foods.
This 192-page cookbook combines the art of gourmet cooking with the science of healthy eating. It features over 100 plant-centered recipes, lists of common foods and their phytochemicals, a phytochemical glossary, and the informative section ?The Science Behind the Recipes.?
This cookbook is available from Produce for Better Health Foundation for $ 17.95 a copy plus $ 5.00 for shipping and handling for a total of $ 22.95. Orders can be placed by calling toll-free 1-888-391-2100. All major credit cards are accepted. Checks, payable to Produce for Better Health Foundation, can be sent to: Produce for Better Health Foundation, Dept. PHYT, 5301 Limestone Road, Suite 101, Wilmington, DE 19808-1249. Please allow 4 to 6 weeks for delivery. Consumers can also place orders over the internet by visiting the 5 A Day website at: http://www.5aday.com.
Phytochemical Brochure Free to Consumers
The Produce for Better Health Foundation has developed a free brochure for consumers titled ?Fruits & Vegetables are as Good as Gold.? This brochure discusses the relationship between fruits and vegetables and good health. It reviews the role of these foods in slowing the aging process and in reducing one?s risk for many chronic diseases, including cancer, heart disease, stroke, high blood pressure, birth defects, diabetes, diverticulosis, chronic obstructive pulmonary disease, and osteoporosis. The brochure discusses the specific phytochemicals found in a wide variety of fruits and vegetables, including citrus fruits, melons, berries, grapes, members of the cabbage family, deep-yellow and orange fruits and vegetables, onions, leafy green vegetables, tomatoes, eggplant, and other fruits and vegetables.
The brochure is free with a self-addressed, stamped business-size envelope. Please send requests to: Produce for Better Health Foundation, Department PHYT, 5301 Limestone Road, Suite 101, Wilmington, DE 19808-1249. Please allow 4 weeks for delivery.
AVOCADO-CILANTRO BAGEL SPREAD
Yield 8 servings
Ingredients:
1 ripe California avocado
1 oz. goat cheese
¼ tsp. onion powder
1 ½ Tbsp. chopped cilantro
1/8 tsp. black pepper
Dash of cayenne pepper
1/8 tsp. salt
1 Tbsp. fresh squeezed lime juice
Directions:
Combine avocado with goat cheese and mix until well blended. Add ingredients and mix well. Adjust salt to taste. Let stand for 1 hour at room temperature to let flavors blend. Serve.
Garnish with fresh lime slices and a sprig of cilantro.
Nutrients per serving: calories, 45; protein, 1g; carbohydrates, 2g; total fat, 3.5g; (saturated fat, 1g; monounsaturated fat, 2g; polyunsaturated fat, 0.5g); cholesterol, 0g; fiber, 2g; sodium, 50mg. (Count as 1 fat exchange).
CALIFORNIA AVOCADO AND SMOKED TURKEY SALAD
IN A BREAD BASKET
Yield 8 servings
Ingredients:
2 loaves of French bread (12-inches long)
2 Tbsp. olive oil
2 Tbsp. balsamic vinegar
8 cups mixed greens
1 cup cubed (½-inch) smoked deli turkey
1 cup cubed (½-inch) papaya
1 cup red or green grapes (halved if large)
1 medium red apple, cored and cubed (1/2-inch)
1 ripe California avocado
seeded, peeled, and cut into crescents
Directions:
Cut one inch off the top of each loaf of bread. Using serrated knife, cut around inner edge of crust and tear out loaf interior. A ½-inch shell should remain. In a small bowl, mix together oil and vinegar. Brush on inside of each loaf. Bake in preheated oven at 375? for 5 minutes. Remove from oven and cool.
In a large bowl, combine greens, turkey, papaya, grapes, and apple. Whisk together dressing and pour over salad. Toss salad and spoon into bread baskets. Top with California avocado crescents. Cut each bread basket into four pieces and serve.
Nutrients per serving: calories, 256; protein, 7g; carbohydrates, 42g; dietary fiber, 5g; fat, 10g; cholesterol, 3mg; sodium, 425mg.
FRUITED COUSCOUS
From the Phytopia Cookbook
Yield 7 servings
1 ½ cups apple juice or chicken broth
1/3 cup dried fruit, such as golden raisins, prunes, or cranberries
1 cup whole wheat couscous
¼ teaspoon allspice
½ teaspoon cinnamon
salt to taste
Bring apple juice or chicken broth to boiling. Add the fruit, couscous, allspice, and cinnamon. Cover, turn off heat and let stand for about 10 minutes. Alternately, microwave for 1 to 2 minutes on low (30% power) until the liquid is absorbed. Fluff with fork, add salt to taste and serve.
Nutrients per serving: calories 152; total fat, 0.1g; saturated fat, 0g; sodium, 8mg; cholesterol, 0mg; fiber, 3g; calcium, 10mg; carbohydrates, 37g; protein, 3g.
Variation: Stir in 1/3 cup of chopped nuts or ½ cup of chopped red or green grapes to couscous at end of cooking.
CRANBERRY-ALMOND MUFFINS
From the Phytopia Cookbook
Yield 12 servings
Nonstick cooking spray
Peel of 1 orange
½ cup sugar
2 eggs, lightly beaten
2 tablespoons canola oil
½ cup light and firm silken tofu, blended
1 ¼ cups unbleached all purpose flour
¼ cup soy flour
1 teaspoon baking powder
¼ teaspoon baking soda
¼ teaspoon salt
1/3 cup unblanched almonds, finely chopped
½ cup dried cranberries, coarsely chopped
Pre-prep: Rinse fruit under running water and pat dry. Remove orange peel with a vegetable peeler, or grate. Blend tofu. Chop almonds and cranberries.
1. Preheat oven to 375? F. Coat muffin tin with cooking spray; set aside. Put orange peel and sugar in the bowl of a small food processor and process 1 or 2 minutes until the sugar is orange colored. Or, mince or grate orange peel and mix with sugar. Turn into a mixing bowl with the eggs, oil, and tofu. Beat with a wire whisk until smooth.
2. Place flours, baking powder, soda and salt in mixing bowl, stir well. Add the almonds and cranberries, then pour the liquid ingredients over dry ingredients and mix quickly just until blended; batter will be lumpy. Resist the urge to overmix or muffins will be tough.
3. Fill muffin cups about three-fourths full. Bake 15 minutes, until golden and springy to the touch.
Nutrients per serving: calories, 166; total fat, 5.7g; saturated fat, 0.7g; sodium, 126mg; cholesterol, 35mg; fiber, 1g; calcium, 40mg; carbohydrates, 25g; proteins, 4g.
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