Each month we are flooded with information about nutrition from the print and online media, from books, and on television and the internet. How are we to know when the information is accurate?
Special-interest groups, particularly in the food and drug industries, have significant influence promoting research about nutrition that is designed to promote their products rather than provide a fair and balanced perspective on food science. Even the USDA, which is responsible for creating Dietary Guidelines for Americans, can be influenced by groups motivated more by self-interest than the common good.1 For example, the original recommendations by the Dietary Guidelines Advisory Committee2 to avoid red meat and limit other animal products were changed so now those guidelines are a nearly-incomprehensible babble about choosing lean proteins!
What can we do to ensure we are making good choices about the recommendations we choose to adopt? There are a number of questions we can ask when reading an article or listening to a reporter that can help us make appropriate choices.
Follow the Money
First, follow the money. Who has funded the study or project that is the center of the story? If the American Egg Board is funding a study about eggs, you should not be surprised if the findings are that you should eat more eggs. But even if the study comes from a reputable university or research group, finding out where the majority of their funding comes from can tell you a lot about how the study was designed. Were the researchers trying to find out what the food or supplement does in the body, or were they trying to find a reason to promote it? A study designed to find out what a food does is more likely to avoid bias than one that tries to find out that a food provides a specific benefit.
Check the Message
Second, look at the message being sent. Is a particular product being promoted? If so, the information presented may be slanted to make you want to purchase the product. What questions are being asked about the problem? Does it seem to be an important problem? A recent women’s magazine promoted a fruit-only diet touted to help women lose 16 pounds in two weeks, just in time for swimsuit season. Does this amount of weight loss in this amount of time seem reasonable or safe, based on information provided in articles and on national health and wellness websites? Does the article go on to explain why this weight loss would improve wellness, or is the focus only on outward appearance?
Examine the Evidence
Third, examine the evidence. Read the original study, if you can. Frequently one small fact is presented from a study, without other, possibly conflicting, evidence being discussed. If it is a very small study, with only a few test subjects, are other studies also presented that corroborate the findings? Has more research been recommended? Have other studies been done with similar or different populations? Were results the same? Sometimes you can find a metanalysis that examines a number of similar studies, which can help you evaluate the information you are receiving. Do the conclusions make sense, based on more than one research study? If the recommendations in the article are followed, what consequences could result—both negative and positive?
Consider the Story’s Assumptions
Fourth, consider any assumptions suggested in the story. In the weight loss article mentioned previously, there may be an assumption that weight loss is always a positive thing, even if it is obtained through unsafe methods, or through eating an unbalanced diet. Is there specific evidence presented for all assumptions made by the author, or assumptions you find yourself making after reading the article?
Evaluate Unscientific or Incomplete Information
Fifth, evaluate information that could be unscientific or incomplete. Many recent authors have stated or implied that carbohydrates, the body’s primary fuel, are bad and should be avoided3,4. No clear differentiation is made between whole-food carbohydrates and refined carbohydrates. Would you consider a stalk of broccoli, a carrot, or an apple “bad?” Do they have the equivalent nutritional value to a sugar cookie or a potato chip? Should all carbohydrates be considered to be alike?
One more caution: While observational studies of large populations are unable to show a direct relationship between a food or substance and a result, they can certainly show a correlation. For that reason, they should also be considered as supplemental evidence, along with clinical trials that can show causation. When it has repeatedly been demonstrated that people who eat more plant foods have, in general, better health outcomes, it would be foolish to ignore that evidence while waiting for long-term clinical trials to support it. It takes 20 or more years to see improvements in longevity. But how much harm will come to you if you begin eating an extra serving of green salad?
Next month: Epigenetics and Plant-Based Eating
1Herman, J (2010). Saving U.S. dietary Advice from Conflicts of Interest. Food and Drug Law Journal. 65(2):285-31