Nutrition Science and Skepticism

Food Choices and Human Health

• Recommendations for daily nutrient intake, or for healthy dietary patterns, should be based on good science
• A single study does not prove or disprove anything
• Popular press and social media are often unreliable sources
• Headlines starting with "A recent study proves..." should be approached with skepticism
• Findings in one study should be repeatedly tested in multiple studies before being considered a theory
• Theories or recommendations should be continuously challenged and revised with new data

Science of Nutrition and Understanding the Quality of Scientific Data

• A single study does not prove or disprove anything
• Popular press and social media are often unreliable sources
• Headlines starting with "A recent study proves..." should be approached with skepticism
• A finding in one study should be repeatedly tested in multiple studies to be considered a theory (e.g., nutrient recommendations)
• Recommendations or theories should always be challenged and revised with new data

The Science Behind Nutritional Recommendations

• The strength of evidence is categorized as: convincing, probable, possible, or not demonstrated
• Assessment of evidence strength may be based on the quantity or quality of data available
• Scientists and policy makers may not always agree

Studying the Health Status and Nutrition Habits of Canadians

• Nutrition monitoring assesses nutrient status, health indicators, and dietary intakes of the Canadian population
• The Canadian Community Health Survey (CCHS) is a cross-sectional survey study of people over 12 years of age
• The CCHS began in 2004 and is conducted every two years (2015, 2017, and 2019)
• Self-reported information on health status and eating habits are collected from over 65,000 Canadians per study

Canadian Community Health Survey (CCHS)

• Objectives of the CCHS include supporting health surveillance programs at national, provincial, and intra-provincial levels
• The CCHS provides a single data source for health research on small populations and rare characteristics
• Information is released promptly and is easily accessible to a diverse community of users
• The CCHS includes a flexible survey instrument which provides a rapid response option to address emerging issues related to the health of the population.

The Scientific Method

• The scientific method is not exclusive to scientists, it's for everyone
• The scientific method, even though euro-centric/westernized, is similar to many indigenous and non-European ways of knowing and learning
• The process is cyclical, usually starting with observation and questions, then forming hypotheses and predictions, followed by experiments, results, interpretations, and possibly leading to new theories, observations, or new questions

Causation or Correlation?

• Understanding reported data requires critical thinking: common sense and considering other factors
• Correlation does not equal causation

Correlation ≠ Causation

• Apparent correlations between variables shouldn't be interpreted as causal relationships immediately
• Other factors could influence the observed relationship

Epidemiological Study, Case Study, Correlation or Causation?

• Epidemiological studies examine correlations between factors (e.g. "X" and "Y") in populations, like "This country's food supply contains more nutrient X, and these people suffer less illness Y."
• Case studies investigate specific cases: "This person eats too little of nutrient X and has illness Y."
• Laboratory studies in animal models help isolate cause-and-effect relationships: "Let's add foods containing nutrient X to some people's food supply and compare their rates of illness Y with the rates of others who don't receive the nutrient."
• Intervention studies are experiments where one group gets nutrient X and the other group does not to evaluate the impact on illness Y.)
• Retrospective studies look back to examine possible relationships.
• Prospective studies track events forward in time.
• Cohort studies study a group over time.

Acne and Vitamin Levels

• New research suggests high vitamin B12 levels potentially correlate with acne development in some
• Further study is needed to definitively link vitamin B12 levels with acne development
• A deficiency in vitamin B12 causes serious health problems

Research Design Terms

• A blind experiment is done where the subjects don't know if they're in the experimental or control group.
• Case studies are studies of individuals, often in clinical settings.
• A control group doesn't receive treatment, but is similar to the experimental group in all respects.
• Correlation suggests a relationship, but not necessarily cause and effect.
• Epidemiological studies analyze disease patterns in populations.
• Experimental groups receive the treatment being studied, compared to control group.
• Intervention studies manipulate a population and observe the results.
• Laboratory studies are tightly-controlled experiments, testing in animals, potentially.
• A placebo is a sham treatment, used for evaluating the placebo effect (healing effect of the treatment itself, rather than the treatment).
• Randomised controlled trials (RCTs, or clinical trials) involve randomized assignment to experimental/treatment and control group.