An Internet WebQuest

PHYTOCHEMICALS AND A HEALTHY DIET

Introduction

Do you like broccoli and cauliflower? Do you eat carrots and peas? Perhaps you drink orange or grapefruit juice for breakfast every day, or eat an apple at lunchtime. Fruits and vegetables such as these are essential to a healthy diet, yet many people do not eat enough of these natural foods. There is mounting evidence that eating a well-rounded diet, consisting of several servings of fruits and vegetables every day, can reduce the effects of aging, and help to prevent diseases such as cancer, diabetes, and heart disease. The chemicals that occur naturally in plants, such as fruits and vegetables, are called phytochemicals. You may have seen television commercials that discuss the health benefits of taking supplements that contain lutein and capsaicin, two types of phytochemicals. What are phytochemicals exactly? What foods contain important phytochemicals? Do you have to eat broccoli to obtain its healthful phytochemicals, or can you benefit equally by taking a pill that contains those phytochemicals? In this WebQuest, you’ll learn the answers to these questions as you explore the nature of phytochemicals.

 

Task

Your job in this WebQuest is to learn all about the phytochemicals found in fruits and vegetables, and the benefits of eating these foods as part of a balanced diet. You will discover what phytochemicals have been studied scientifically, and what these research studies have discovered. You will learn about the different phytochemicals that can be found in natural foods, and the health benefits of each type. You will fill in a table in which ten different foods or groups of foods are listed. For each food or group of food, you will list the important phytochemical(s) each contains, and the health benefits of eating that food. Finally, you will answer a few questions about phytochemicals to demonstrate what you have learned in your Internet research.

 

Resources

Look at the web sites given here to find the information that will enable you to complete your table on phytochemicals and answer a few questions.

• Antioxidants and Other Phytochemicals: Current Scientific Perspective. Go to this site to read about the results of clinical trials that examined the benefits of antioxidant phytochemicals such as vitamins C and E and beta-carotene (which the body converts to vitamin A).

• Phytochemicals and Cardiovascular Disease. Go to this site by the American Heart Association to find out what phytochemicals are being used to treat heart disease. The Association recommends that people eat more fruits and vegetables to obtain the optimum benefits from a healthy diet.

• The Phytochemical Collection. Visit this site by Florida State University for a brief history of the importance of including fruits and vegetables in the diet. Scroll down to see a listing of phytochemicals that have been shown scientifically to combat diseases.

• PhytoChemicals - Nature's Wonder Compounds

• What are the benefits of Vitamins and Phytochemicals? This site from Oregon State contains images, links, references, and instructional materials on food and their resource. You'll find a list of many foods containing phytochemicals beneficial to health.

  Antioxidants

  Beta Carotenes

  apricots, cantaloupe, carrots, collard greens, fennel, kale, mustard greens, peaches, pumpkin, red pepper, romaine lettuce, spinach, sweet potatoes, Swiss chard, winter squash.

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  Vitamin C

  broccoli, brussel sprouts, cantaloupe, cauliflower, citrus fruits, green pepper, kiwi, papaya, peaches, red cabbage, red pepper, strawberries, potatoes

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  Vitamin E

  wheat germ, seeds, nuts, dark green leafy vegetables, avocado, peanuts, sweet potatoes

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  Lycopene

  tomatoes, apricots, guava, pink grapefruit, mango, oranges, peaches, papaya, watermelon

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  Lutein/ zeaxanthin

  kale, broccoli, spinach, winter squash, Brussels sprouts, celery, dill, leeks, mustard greens, peas, green onions, summer squash

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  Lipoic acid

  dark leafy green vegetables, especially spinach and broccoli

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  Flavonoids

  apples, citrus fruits, flaxseed, lentils, onions, peanuts, rice, soybeans, blueberries, cranberries, currants, olive oil, red wine, green tea, chamomile tea, black tea

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  Polyphenols

  chocolate, coffee, grapes, nuts, oranges, strawberries, green tea, black tea, red wine

   

  Class	Phytochemicals	Food
  Carotenoids	Beta-carotene Lycopene Lutein	Citrus fruit, broccoli, sweet potato, carrot, tomato
  Glucosinolates	Dithiolthiones Sulfuraphane Isothiocyanates Indoles (products of glucosinolate breakdown)	Cabbage, kale, broccoli, cauliflower, Brussels sprouts
  Flavonoids	Catechins Theaflavins Anthocyanins coumarin Quercetin Myricetin	Tea, berries, wine, carrot, citrus fruit, nuts, pear, apple, endive, cranberry, broccoli, onion, kale, leaf lettuce, green bean
  Flavones/ Isoflavones	Apigenin Luteolin Genistein Daidzein	Celery, olive, tofu, soybeans, soynuts, miso, soy milk, soy cheese, TVP
  Phenolic acids	Ellagic acid Gallic acid Ferulic acid Chlorogenic acid Neochlorogenic acid Caffeic acid	Blueberry, pear, sweet cherry, apple, orange, grapefruit, white potato, grape juice, coffee beans, prune, strawberry, raspberry
  Phytoalexins	Resveratrol	Grape, peanuts
  Monoterpenes	Mycrene d-Limonene Carvone	Citrus fruit, peppers, basil, thyme, caraway, whole grains
  Diterpenes	Carnosol, Rosmarinic acid	Oregano, rosemary
  Triterpenes	Glycyrrhizin 6-Gingerol Zingiberene	Citrus fruit, soy, licorice
  Sulfides	Allyl sulfur	Garlic, leek, chives, onion, shallot
  Xanthophylls	Zeaxanthin Cryptoxanthin	Corn, egg, spinach, collard greens