Evaluating Health Claims

In fall of 2015 newscasts and headlines were abuzz with the announcement that meat causes cancer. One CNN headline bemoaned, “If meat causes cancer, what can we eat?” Truthfully, any person that believed many of the claims in this article, such as the claim that cheese and sugar are as addictive as drugs, might believe the article that the only way to balanced nutrition is the fad diet that is described in the article.

When taken as reported, the information in the article might change an individual’s entire lifestyle. However, as this class will continually demonstrate, headlines and health claims are often misreported and/or misrepresented. Worse, some fad diets cause more harm when people act on them.

Informed people will examine all claims made about food and health. Making health decisions based on newspaper, magazine, broadcasts, or word of mouth is dangerous, so it is the responsibility of informed people to follow some basic steps to assess the validity of health claims.

Examining the meat as a carcinogen claim from the CNN article allows exploration on how to assess health claims. To be fair, CNN was not the only national news source to lead with the headline that meat causes cancer, but this was one of the more inflammatory reports on the news.

Step One: Reasonable and rational evaluation

Logically, if the headlines were true, what would the end result be? Humans evolved as omnivores which means humankind has been eating red meat for thousands of years. If all red meat causes cancer, wouldn’t the incidence rate of cancer be much higher?

Step Two: Look for corroboration

How many other sources mention the same or similar headlines? If it appears only one time, or if all of the sources for the basic information seem to reference one another instead of a more authoritative source, consider that the information might be misleading or incorrect. In this case, there were lots of headlines along the same lines, but all of the articles referenced one central source.

Step Three: Go to the original source

Digging deeper into the articles proved that the International Agency for Research on Cancer (IARC), a subsidiary of the World Health Organization (WHO), had conducted a study in which twenty-two experts from ten countries did an analysis of 800 earlier studies to conclude that processed meats when eaten in high amounts are probably carcinogenic. The original source is much more nuanced than the headlines suggest. For example, the CNN article leaves out the study’s more cautiously-worded finding that the link between red meat and cancer is based on “limited evidence.”

Step Four: See if the results are replicated

Sometimes an original source is reporting results from one experiment. Scientists and medical health professionals are suspicious of any claim made by a study that can’t be replicated. Notice that the study mentioned by the WHO was actually a meta-analysis of multiple studies done over time. Most reputable studies wouldn’t claim to have all of the answers without asking for more complete work.

Step Five: Examine credentials

Organizations and professionals who are reputable will always cite where their information came from and how they arrived at their conclusions. Examining the organizations and individuals who published the first study can help to establish how trustworthy the information is. For example, Jen Christensen, the CNN writer, is not an author of the study. According to her profile, she is part of CNN’s Health, Medical & Wellness Unit, which seems like a reasonable background to write about the study. However, CNN is not an authority on health information. The purpose of a news agency, like CNN, is to inform by writing and distributing news. Often times in order for information to be consumed by people, a news agency might seek to boil complicated science down to the most attention-grabbing headlines. The WHO and IARC, in comparison, have a long history of conducting solid studies on health issues related to an international audience.

Sometimes it isn’t clear whether the organization or person sharing what looks like credible scientific research is trustworthy. One way to establish a scientist’s credibility is to look at what other scientists are saying about the individual. Organizations like Quackwatch can help to identify people who report pseudoscience. However, there is no substitute for critical examination of health information.

You Try It:

In the CNN Article there is a claim that “cheese and sugar may be as addictive as a drug.”  Follow the steps outlined on this page to decide if you believe the claim as presented. Be sure that you can describe your reasoning at each step.