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About This Episode:
Numerous nutrition studies present findings of “no effect,” but interpreting such results requires caution. A null finding, indicating an absence of impact from a nutrient or exposure, may not necessarily suggest a lack of effect overall. Instead, it could stem from issues related to the study’s design, the nature of the exposure, or participant characteristics.
We’ve often referred to such studies as being “null by design”.
These studies, often termed “null by design,” may yield inconclusive results due to insufficient contrast in exposure levels to reveal a significant effect size. Additionally, participants’ baseline nutrient status or intake can contribute to false negatives. For instance, if a study provides a nutrient to individuals already replete in that nutrient, it may lead to an erroneous conclusion. This phenomenon can be understood by considering the bell curve of activity for a nutrient.
Moreover, a lack of methodological rigor can generate ‘false negatives.’ If previous literature indicates associations between high intake of a specific food or nutrient and certain outcomes, a study comparing levels of intake well below that threshold may produce a misleading result.
Some challenges arise from an overly reductionist perspective. In disease processes, reductionism simplifies diseases to a single primary source at the cellular and molecular level. This perspective assumes that if a nutrient shows a relationship with health or disease outcomes at a population level, its biological activity should manifest in isolation. However, applying such assumptions to exposures like diet may not be tenable.
In this discussion, we delve into the concept of “null by design” and present three specific studies with null findings, emphasizing the need for careful interpretation.
Listener Q&A: Homocysteine, MUFA, Healhty BMI, and more! (Preview)
#506 Sports Nutrition: Translating Research to Practice – Andreas Kasper, PhD
#505: Oslo Diet-Heart Study: Cholesterol-lowering Diets & Cardiovascular Events
#504: Vegetable Oil vs. Saturated Fat – Analysis of the LA Veterans Study
#503: Lyon Diet Heart Study – Canola Oil, “Mediterranean” Diets & Minimizing Bias
#502: Sydney Diet-Heart Study – Is Linoleic Acid Causing Heart Disease?
Addressing Some Criticisms of Nutritional Epidemiology (SNP 23)
#501: Sex-based Training Recommendations: Evidence-based or Hype? – David Nolan, PhD
#500 – The Big Unanswered Questions in Nutrition Science
#499: How Sensory Cues Impact Food Choice & Behavior – Prof. Ciarán Forde
The PREDIMED Trial – Controversy, Criticisms, & Lessons Learned (SNP 22)
#498: The PROPEL Trial & Weight Loss Interventions in Primary Care – John Apolzan, PhD
#497: Are Food Frequency Questionnaires Reliable?
SNP21: Sick Individuals and Sick Populations
#496: ATBC Cancer Prevention Study – Crucial Lessons
#495: Circadian Clocks in Muscle & Exercise as a Time Cue – Prof. Karyn Esser
#494: Multiple Risk Factor Intervention Trial
#493: The Keys Equation – How Dietary Fats Impact Blood Cholesterol
SNP20: The Cumulative Exposure Model of LDL-C & Heart Disease
#492: How Does Weight Cycling Impact Long-term Health?
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