Thinking Critically about Scientific Information

Amy Allen-Chabot (amallen@mail.aacc.cc.md.us)

Rob Haroth (rharoth@umuc.edu)

Match the following pieces of information gleaned from various articles with one or more of the 18 ideas laid out by Joe Schwartz and Stephen Barrett on the “Some Notes of the Nature of Science” web page.

You can access Dr. Barrett’s web page by clicking on http://www.quackwatch.com//01QuackeryRelatedTopics/science.html

Print the two page report by Dr. Schwartz and Barrett so that you can look at it while reading each of the situations below. Scan down the printed page until you reach the words “The following ideas can help you evaluate information you encounter about science and health”. Match each of the situations below with the one or more of the 18 ideas listed by Dr. Schwartz and Barrett under this subheading.

Scenario or scientific information	Concept(s) or Idea(s) from “Nature of Science” web page. For each of the numbered items on the left, list the number of each applicable concept from the Nature of Science web page, followed by a one sentence statement summarizing how the idea or concept relates to the scientific information or situation on the left. Several situations have more than one concept or idea that relate so list all ideas that are applicable. The first situation has already been completed as an example
1. Some research in recent years has suggested that St. John’s Wort may be helpful in relieving depression. Due to this connection, many individuals began taking the popular natural herbal remedy. Unfortunately, a more recent study suggests that the St. John’s Wort may reduce the effectiveness of birth control pills.	3. Neither scientists nor the public predicted in advance that St. John’s Wort would reduce the effectiveness of birth control pills. 13. St. John’s Wort is a natural plant product but it can have powerful effects on the body, demonstrating that nature is not benign.
2. Results of case-control studies and of a prospective investigation in men suggest that consumption of coffee could protect against the risk of Parkinson's disease. The several studies that have been done on this relationship are less than 5 years old and are observational studies involving data collected about coffee consumption and Parkinson’s disease in existing populations.
3. Alonzo read a recent study suggesting that zinc lozenges help reduce the severity of the common cold. Since Alonzo gets several colds a year, he decides to routinely suck on several zinc lozenges each day and also take zinc supplements in pill form. Since his colds eventually go away, he assumes the zinc is working and stays on the regime. Eventually he develops a copper deficiency because the high intakes of zinc can reduce copper absorption in the small intestines.
4. Brad goes to the doctor for his high blood pressure. The doctor suggests that Brad reduce his sodium and explains that research shows sodium reduction reduces blood pressure in some but certainly not all individuals. Brad reviews the literature and finds that there is much disagreement among scientists about the benefits of sodium restriction for controlling blood pressure. Brad sighs and states that he would like to know for sure if it will be effective before he gives up his favorite high sodium foods!
5. Jenny is concerned about cancer because her father died of colon cancer at 52 years of age. She knows that there is a significant amount of research suggesting that high intakes of fruits and vegetables reduce your risk of cancer. She hates fruits and vegetables but knows they are high in antioxidant nutrients so she decides to take antioxidant supplements.
6. Wanda is pregnant and very concerned that the aspartame in her soda may cause birth defects. She lights a cigarette on her way to the store to buy regular soda.
7. Sandra has put on quite a bit of weight in the past and wants to take the weight off. She recently saw a diet advertised in a women’s magazine that indicated she could lose 10 pounds in two days and eat whatever she wants. She was really excited and plans to go on this diet immediately.
8. The National Weight Loss Registry shows that people have had success losing weight an a number of diets including the Atkins high protein, low carbohydrate diet. (as we all know, its KEEPING it off that is problematic). She decides to follow the diet since it has worked for others. After 6 months, she notes that she has not lost weight and has developed kidney disease. She can’t understand how this could happen. She didn’t see any reports of this happening to others when she went to the Atkins web page.
9. Mira is shopping at the grocery store and picks up a half gallon of ice cream. Since it is a brand she is unfamiliar with, she reads the ingredient label. Listed in the ingredients is “locust bean gum and carrageenan”. She is really concerned about these ingredients…they sound really bad. Later, she shares her concerns with her nutrition teacher and her teacher informs her that these ingredients are healthy carbohydrate-based compounds that are used as thickeners in foods.
10. Many modern scientists have debunked several aspects of Darwin’s original theory of evolution. Based on this, many web pages state that his theory of evolution is not true.
11. Beta-carotene, a vitamin A precurser, is a known antioxidant and believed to play a role in neutralizing cancer triggering compounds called free radicals. Furthermore, foods high in antioxidants (like fruits and vegetables) have been correlated with reduced risks of cancer. Based on this, scientists decided to run an intervention study using smokers. They hypothesized that smoking will result in increased numbers of free radicals in the body and beta-carotene neutralizes those free radicals, so beta-carotene should reduce the incidence of lung cancer in smokers. Beta-carotene was given to a group of smokers. An equal number of smokers were given a placebo. Much to the dismay of the researchers, the smokers receiving the beta-carotene actually had a significantly greater incidence of lung cancer than the smokers receiving the placebo. Researchers were quite surprised and had not predicted that the beta-carotene might INCREASE the risk of cancer.
12. The data linking beta-carotene to reduced cancer risk can be disputed because it is difficult to determine the beta-carotene content of foods and measure dietary beta-carotene intake. However, evidence that higher fruit and vegetable intake is consistently associated with reduced cancer risk at most sites remains unchallenged.
13. Saccharin has been reported to induce urinary bladder tumors in rat feeding studies and to promote bladder cancer in rats initiated with known bladder carcinogens. For this reason, saccharin was almost pulled off the market. Diabetic patients lobbied heavily to keep saccharin on the market and congress eventually allowed its production albeit a warning label has been added. Interestingly, bladder cancer in humans has not risen since saccharin was added to the food supply, suggesting that the findings in rats did not translate to humans as expected.