By Beth Maschoff, RD, LD

Almost daily we are presented with another nutrition study that appears to contradict what we learned last year or even last week.  It can be confusing to know what to believe.  Too often the results are overstated or misinterpreted by those delivering the headline. Even if not intentional, it can be difficult to know how to interpret what you hear or read, and more importantly, understand if it warrants making a dietary change.

We’ve put together these tips to help you put these headlines into context, or at least separate reliable science from journalistic hype:1

  • Words matter:
    • Watch for words such as: “preliminary” or “initial findings,” they are interesting, but more evidence is needed.
    • “Suggest” doesn’t mean “prove,” and “linked to” and “associated with” aren’t the same as “cause.”2
    • Remember that “significant” refers to statistical significance related to what was being studied and is not the same as “important.”2

Take-awayBe a discerning and understand that the headline is meant to draw you in, not compare or review the findings comparatively to other research.

  • Study design makes a difference:
    • Newer is not always better
      • The latest study is not necessarily the most reliable nor does it automatically invalidate previous research.1
    • Was it from a single-study?1,3
      • Change in dietary advice is rarely based on the results of one study on its own. Typically, the findings need to be replicated and validated by additional research, fitting into a “bigger scientific puzzle.”2
    • Was the study done on humans, on animals or in vitro (in a test tube)?
      • While animal and in vitro studies are often important first steps, human nutrition doesn’t always correspond to studies done in a lab or on animals1-3
    • How large is the study?
      • The larger the number of participants or sample size, the more reliable the statistical conclusion 1,3
    • What was the study assessing?
      • Look for those that study actual disease endpoints such as diabetes, heart disease and osteoporosis versus those that only study markers for those diseases because they don’t always translate into developing the particular condition.1
    • How was the diet of the participants assessed?
      • Studies that deliver the food and nutrients to participants and then measure certain outcomes, called controlled feeding studies, are more reliable than a “self-reported” diet where participants are asked to recall what they ate.1
    • What type of study was done?

Below is a list of study types in increasing order of scientific strength and decreasing bias:

  • Expert opinion is merely that, one person’s opinion. It is not evidence.
  • Cross-sectional studies are observational studies examine one point in time to assess a disease risk factor or exposure.2
  • Prospective Cohort studies follow large numbers of participants for years to monitor certain disease outcomes.1
  • Randomized Clinical Trials (RCTs) are considered “the gold standard” for dietary interventions because participants are randomly assigned into either an experimental or placebo group. They are also more rare because they are resource-intensive and expensive.1

Take awayCertain research design parameters and study types are more reliable than others; understanding this can help you interpret the results. Nutritional guidelines and policies are ultimately informed by the combined evidence from all of these study types.1

  • Consider the source:
    • Where did you read or hear the headline? Instagram, shared Facebook posts or morning talk-shows are not as reliable as learning the information from an educated nutrition professional, such as a Registered Dietitian, who has thoroughly vetted the information and put it into context.
    • Look for information validated by website domains ending in .org, .gov and .edu.
    • Remember the headline is often only one piece of the findings from a full research study.2
    • Articles published in peer-reviewed professional journals are typically more reliable because they must meet certain research standards and are reviewed by their professional peers.2,3

Take awayBe discriminating about the origin of the headlines and read the entire article to understand the complete context.2

And the final take-way? Maintain a healthy skepticism and trust your highly educated Livea team to guide you through thoughtful interpretation of the latest nutrition “breakthrough.” We will help you put the science into perspective and whether it could or should relate to you and your eating plan.

And remember, scientific debate is healthy and important.  Contradictions are an inevitable part of the scientific process and what helps nutrition science advance.2

Resources:

  1. Harvard T.H. Chan School of Public Health. Diet in the News – What to Believe?. The Nutrition Source. https://www.hsph.harvard.edu/nutritionsource/media/. Published March 18, 2016. Accessed October 1, 2019.  
  2. Duyff RL. Academy of Nutrition and Dietetics Complete Food & Nutrition Guide. Boston: Houghton Mifflin Harcourt; 2017.
  3. Harvard T.H. Chan School of Public Health and The Culinary Institute of America. Tool Kit Resource: What Builds Strong Evidence on Diet and Health?. Menus of Change. http://www.menusofchange.org/images/uploads/pdf/What_Builds_Strong_Evidence_on_Diet_and_Health_FINAL1.pdf. Accessed October 1, 2019.