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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.
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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.
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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.
- Phytochemicals
- Vitamins of the Future? Visit this
Ohio State University site to learn more
about the use of phytochemicals to combat
many types of cancer. The American Cancer
Society suggests that people eat mostly plant
foods to combat cancer rather than animal-based
foods. At this site you can see a list of
foods and the phytochemicals they contain.
- 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:
Guardians of Our Health. At
this site you can read about the anticancer
potential of foods such as garlic, soybeans,
cabbage, ginger, licorice, and carrots.
Scroll down to read about the health
benefits of soy, citrus fruits, and whole
grains.
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Time
1 class period for research, filling in the
table, and answering a few questions.
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Process
Now that you have completed your research
on phytochemicals, prepare a table like the
one below with the information that you have
gathered about the foods listed. For each food
or group of foods, list the phytochemicals
they contain, then list the health benefits
of the phytochemicals or the diseases that
those phytochemicals can be used to treat.
You will need to look at all of the web sites
listed in order to complete the table. Once
the table has been filled in, answer the questions
that follow.
Table 1. Phytochemicals and a Healthy Diet
| Food |
Phytochemical(s) |
Health
Benefit/Disease Treated |
| Broccoli,
cauliflower |
|
|
Garlic |
|
|
| Onions |
|
|
| Citrus
fruits |
|
|
| Tomatoes,
peppers |
|
|
| Grapes,
berries, cherries, apples, cantaloupes |
|
|
| Soybeans,
beans, oats, seeds, whole grains, brown
rice |
|
|
| Licorice
root, green tea |
|
|
|
Spinach |
|
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Questions about Phytochemicals and a
Healthy Diet
- Scientific studies have shown that phytochemicals
are associated with prevention and treatment
of four leading causes of death in the United
States. What are they?
- Many vegetables are prepared by cooking,
such as broccoli and cauliflower. Does cooking
destroy the phytochemicals found in these
foods?
- Health food stores already sell some phytochemicals
in pill form. Does taking phytochemicals
in a pill form provide the same health benefits
as eating the food itself?
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Conclusion
In the process of completing this WebQuest,
you've become informed about the importance
of including fruits and vegetables in your
diet. You have learned what phytochemicals
are and what foods contain important phytochemicals.
You have developed critical thinking skills
as you explored the health benefits of phytochemicals.
To protect yourself from developing diseases
such as cancer and cardiovascular disease in
the future, what changes should you make in
your diet today?
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