Make your own free website on

Applied Nutrition
Internet Assignment 4

Read the follow material and use the internet to obtain information.
Answer the questions on a separate text document such as MS Word, Notepad or Write then send it to me as an e-mail attachment at

Assignment Four
Antioxidants & Vitamins

Before we look for information on this subject, let's review the five questions we want to ask of each source of information: 

  • Who wrote the information? 
  • Who is paying the bill to publish the information? 
  • Is there an inherent bias? 
  • Do the authors quote research that can be checked or repeated? 
  • How recent is the information? 


Also, let's review the domain endings that will give us a clue as to the source (and bias) of the information.

  • Government sites, including 3 huge federally-funded national libraries. These sites have domain names ending in .gov 
  • Educational institutions: universities, colleges, &research institutions. These sites end in .edu 
  • Commercial enterprises, everyone trying to sell you something. These sites end in .com 
  • Non-profit organizations. These sites end in .org or in .net 

I've run a quick search through Google, and come up with a list of many sites. A fast glance through the URLs of these sites will give me some clues as to their origin. Unfortunately, these clues are sometimes misleading:

  • One of my results was from a commercial site, but does give an author, a date, and a list of references at the end of the page. 
  • Another result list item was an article from a non-profit organization, Annals of Internal Medicine, reporting on a study of the literature concerning antioxidants and cardiovascular disease. Unfortunately, it was published in 1995, and possibly new findings have been discovered in the last five years. 
  • Another item with an org domain name, supposedly from a non-profit organization turned out to be something quite different. If we go back to the first level domain name of this site, we can get a clear picture of the true purpose of this website. 

Remember, to do this, put the domain name in the location bar by itself, with none of the following directories and documents. 

Question 1
What do you think the purpose of this website is? 


This assignment  talks about several ways that free radicals are created in the body, those nasty unstable molecules that are thought to be the cause of over 200 diseases, plus the physical effects of aging. The textbook lists aerobic exercise as one of the factors that increase free-radical formation. Are all those runners pounding the pavement really just increasing their potential for 200 diseases, plus aging faster? 

Let's use the search engine, Yahoo to find more information about this:

Here's what your search screen will look like. Type in the words free radicals in the search rectangle. 

Notice the advanced search: words on the right side of the screen:

Click on advanced search then

The boxes provided reads all the words, exact phrase, choose  exact phrase


This will tell the search engine to find only the articles that have these 2 words together, in this exact order. 

Click on the Yahoo Search button and see what comes up.
Question 2
How many matches did your search find? 

search options at hotbot


The some articles on my list are about a band called the Free Radicals, and some are advertisements for herbal remedies and oatmeal. Plus, I don't want to scroll through more than 60,000 sites looking for something about free radical formation through exercise. So let's refine the search by adding more terms and using Boolean logic


Boolean logic is named after a mathematician by the name of George Boole, and is a way that we can narrow our topic, get fewer and more relevant results. 

Here's how it works. If we type in "free radicals", the search engine will find all records that contain that term. If we type in "free radicals" AND exercise, the search engine will look through all the "free radicals" results, and pick out just those that also contain the term exercise, which means many fewer. In this diagram, if all the records with "free radicals" are represented by the blue circle, and all the records with "exercise" are represented by the yellow circle, the result list would be only those records falling into both circles, the overlapping green section:

Boolean diagram

Scroll back up to the top of the site and change your search terms to:

"free radicals" + exercise

This tells the search engine to look for all articles that have the phrase, and also have the term 'exercise'. 

Click on the search button. 
Question 4
Now how many web results do you get? 

Note the list still includes pages about a movie "Kino Film: Free Radicals " because it  includes words exercise in montage

Question 4A 

How could you exclude this type of page from your Yahoo search?


One of your first entries should look like this: 

Rice University listing from hotbot

at least looks like it's coming from a 4-year university. 
Question 3
How can you tell? (Hint: remember those domain names.)

Look closely at the URL of this site, though:

url for site

That tilde (~) right after the domain name means that this is a personal site, somebody who works at Rice University, or is associated with the school, but not necessarily condoned or supported by it. Click your mouse button twice at the end of the URL in the location box, or until the highlighting disappears. Now use your delete button to erase both the document (antiox.html) and the last folder (sports). You should be left with:

Hit the Enter key, and this personal page should come up on your screen. 


Question 4 to 6

  • If you click on the Medical Tent button, you can find a couple of names associated with this site. Who are these people and what credentials do they have? 
  • Click on the back button until you get the article displayed again. Do the authors cite research or tell you where they got their information or do they just list some relevant references?
  • What date can you find for the page? 

This is the kind of detective work you'll have to do in order to evaluate the quality of many websites. Remember that anyone can post anything to the Internet. There is no editor or publisher in charge to check even spelling, much less facts. 


Go back to the Yahoo search engine and try adding another term to your search strategy. This time we'll search for: 

"free radicals" + exercise + beta-carotene

In this search, the computer will find documents that contain ALL THREE terms, which means that our result list will be even smaller. 
Question 7
In the Boolean diagram at the right, what colour represent these documents? 

boolean diagram with 3 terms

Question 8
How many hits do you get in Yahoo search with this strategy?


Question 9
Look through your result list, analysing first by the domain name in the URL, then visiting a few that look promising. Describe one of the better ones (most useful, most entertaining, most academic, or most bizarre). In your description, be sure to include the URL of the site, and answer these questions: 

Who wrote the information? 

Who is paying the bill to publish the information? 

Is there an inherent bias? 

Do the authors quote research that can be checked or repeated? 
How recent is the information? 


Boolean searching works the same way in EBSCOhost, which is the periodical index for general and popular magazines, and some professional journals. Remember that you must click on the  Ebscohost hyperlink to choose the type of search. 

From the EBSCOhost  screen, select the data bases you want to search.  Choose health related data bases

Then click Continue


Question 10
First try one term:  Type these words in the Find box and press Search
free radicals
How many hits did you get? 


Question 11
Now two terms:
free radicals and exercise

Use  " and" not + this time
How many hits did you get?


Question 12
And finally 3 terms:
free radicals and exercise and beta-carotene
How many hits did you get?



You should be getting fewer hits every time you add another term. If you aren't, go back and check your spelling.

 Every time you add another AND another term, your result list will be smaller and, if you've chosen your terms carefully, more precisely on your topic. Isn't Boolean logic grand? 


Glance through some of the items on your result list. These are the types of articles that the general public could refer you too . 
Question 13
Describe one , including the name of the magazine that published the article, the author of the article (if you can find one), and the title of the article. Jot down any names, any studies, any key words that you might be able to use if you wanted to search Medline for the subject of this article.


Let's try using Boolean logic in Medline. Medline handles Boolean searching differently than many of the Internet search engines. The Medline engine will assume an AND between all terms, unless the terms are held together with quotation marks. 

Medline search screen with 3 terms

For a Medline search on all three terms, we would type:

"free radicals" exercise beta-carotene

Medline will treat the terms as three separate words, and automatically put AND between them. free radicals will be one 'word' because it has the quotation marks around it. 

Try the three searches in Medline: 

First try one term: "free radicals"
Question 14
How many hits did you get? 

Now two terms: "free radicals" exercise
Question 15
How many hits did you get? 

And finally 3 terms: "free radicals" exercise beta-carotene
Question 16
How many hits did you get? 


Glance through some of the items on your last result list. To read the abstract (summary) of any of these articles, remember that you can click on the author's name.

 These articles describe the actual medical research, studies and randomized trials, that you can use to answer patient questions. 

Search Medline again, this time using one or more of the words you jotted down for the Ebsco article. You might have to try adding terms to narrow your result list. If you get no hits, look through your list of terms and start taking out the least important terms. Successful searching involves trial and error. 
Question 17
Describe one here that possibly answers the claims made by the article you found in EBSCOhost above. Include the title of the journal that published the article, the author of the article, and the title of the article. Also include the search terms that were most successful.

purple line

road sign


In this lesson, we've spent most of our time fine-tuning searches by adding terms using the Boolean connector AND. Remember that every time you add another term, connected by another AND, your result list will get smaller and more finely tuned. If you pick your terms carefully, you should end up with a short list of articles that are exactly on your topic. 

There are other Boolean connectors that we'll use later, like: 

  • OR which will broaden your search and increase the number of hits on your result list. 
  • NOT will exclude certain records. If you wanted to see articles on the effects of the three-strikes laws in California, but you kept getting articles on baseball, you could search for 

three strikes NOT baseball

  • NEAR will find records for you that don't quite contain your terms as a phrase, right next to each other, but very close. If you searched for "Nancy Drew", you would only get the records that have her name exactly like that. If you searched for "Nancy NEAR Drew", you would get records that use 
    • Nancy Drew, 
    • Nancy Q. Drew, 
    • Drew, Nancy
    • and so on.

You've had more practice evaluating websites and figuring out who is posting and maintaining the sites. 

You've had another opportunity to play with the Hotbot search engine, and one more chance to experiment with Medline. Remember that Medline is the database for all the professional print literature, those peer-reviewed and editor-controlled printed journals that are so very different from the Internet, where nobody is in control and nothing is checked. 

purple line

You're almost finished
Make sure you add your  name, I.D.,  and your e-mail address to your answers , save a copy of your work  on disk then   send your answers to me as an  attachment   to an e-mail.   My e-mail address is:

purple line

Address of this page:
For questions or comments, please send e-mail to
Barry Brazier at
Last updated on August 28, 2002.

Return to Applied nutrition Assignment list

This assignment were based on similar work sheets set by: