Unit 1
General Principles of Research in Nutrition

Overview

Nutrition is a rapidly expanding science. Indeed, knowledge in the area has increase exponentially in the last three decades. Often, however, today’s “discovery” is tomorrow’s discredited idea. For instance, the importance of dietary factors supposedly involved in such disorders as breast cancer (fat), the common cold (vitamin C), obesity (high fat intake), hyperactivity (food additives), and stomach cancer (nitrates) have been both “proven” and “disproven.” Why is there such confusion? The perennial problem of nutrition is that it is not an exact science: rarely does it have the precision of physics or chemistry. Deductions tend to be based on ambiguous evidence.

In this unit, we look at how nutrition research is conducted. From this investigation, you can learn how to make your own assessments of claims in nutrition. Hence, the main part of this unit is an explanation of the different techniques for conducting nutrition research, including a discussion of the advantages and disadvantages of each method.

Objectives

After completing this unit, you should be able to

  1. identify and discuss eight different types of evidence used in establishing the role of diet in disease:
    1. anecdotal evidence;
    2. evidence derived from population studies;
    3. historical evidence;
    4. evidence derived from case-control and cohort studies;
    5. evidence derived from cross-sectional studies;
    6. evidence derived from intervention studies;
    7. evidence derived from animal studies; and
    8. evidence derived from biochemical and physiological research.
  2. assess the reliability of evidence purporting to demonstrate a diet-disease relationship.
  3. define “food faddism,” and discuss the problem this phenomenon creates.
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