Comment on the Importance of Physicians' Nutrition Literacy in the Managment of Diabetes Mellitus

     Schulman and Rienzo¹ have again emphasised the importance of nutrition in medical practice and hence the need for the subject in the medical curriculum. However, the teaching of nutrition faces problems not found in other disciplines. We all eat. From an early age we form opinions on the desirability or otherwise of certain foods, based on our personal likes and dislikes of their flavours and textures and on beliefs held by parents, peers, the media and the culture. Everyone has these opinions, which may be neutral, contradictory or confirmatory to current scientific thinking. Students bring these beliefs to the medical course. New scientific information on nutrition presented in the course must therefore compete with pre-existing beliefs. The psychological theory of hindsight bias^2,3 shows that it is harder to replace pre-existing false knowledge (some would prefer the term "false beliefs") with correct knowledge than it is to fill a knowledge void with correct knowledge. Some years ago we demonstrated that students and health professionals carry considerable false knowledge about nutrition.⁴ Studies in engineering have shown that tertiary training may not undo such false beliefs in basic physical principles.⁵ Recent papers have shown that nutrition teaching modules convert much ignorance into correct knowledge but have much less effect on pre-existing false knowledge.^6,7

     We have asked medical students to answer a set of MTF questions relating to a patient with Type 2 diabetes. Thirteen of the 42 questions related to nutritional management. These questions were answered by students on entry to the graduate medical course, after two years of training and again in their fourth year after they had completed their final medical clerkship. A summary of the answers is shown in Table 1.

     There is no formal module dedicated to nutrition in the graduate medical course in Queensland, the subject is included in all appropriate preclinical and clinical studies. There has been a healthy increase in correct knowledge of nutrition over the four years of training, mostly by replacing ignorance with correct knowledge. The fall in false knowledge has been more modest, and near the end of their medical course 13% of all student beliefs about nutrition were false by current standards. Individual questions retained their ranking with respect to levels of true knowledge and false knowledge in all three samples. The question with the highest overall level of false knowledge was "the main factor in reducing body weight is to reduce calorie intake so that it less than calorie output rather than change the type of food eaten.". Before starting the medical course 50% of the students considered this statement wrong, by Year 4, 57% considered it wrong.

     Prior knowledge, both true and false, among medical students is not confined to nutrition, but is more prevalent there. Effective teaching and training in the discipline will therefore need considerable resources and innovative methods to overcome this in-built handicap.

     Professor Ken Donald, Head of the Graduate Medical School, University of Queensland, Australia has given permission for the collection of the data and the publication of the results. I thank Dr Heather Alexander for organising the collection of the data.

Alan Dugdale MD FRACP
71 McCaul Street, Taringa Q 4068, AUSTRALIA
E-mail : A.Dugdale@mailbox.uq.edu.au

REFERENCES

1. Schulman JA & Rienzo BA The Importance of Physicians' Literacy in the Management of Diabetes Mellitus Med. Ed. Online, 2001, 6, 6
2. Christensen S Jay J Willham CF The hindsight bias : a meta-analysis Organizational Behaviour and Human Decision Processes 1991, 48, 147 - 168
3. Hertwig R Gigerenzer G Hoffrage U The reiteration effect in hindsight bias Psychological Rev., 1997, 104, 194 - 202
4. Dugdale AE Chandler D Baghurst K Knowledge and belief in nutrition Amer. J Clin Nutrit. 1979, 32, 441-445
5. Johansson B Forces in motion. Technological students conceptions of some basic phenomena in mechanics (original in Swedish) Reports from the Department of Education, University of Gothenberg, 1981
6. Hodgson CS Tracking knowledge growth across an integrated nutrition curriculum Acad Med 2000, 75, S12 - S14
7. Dugdale AE Alexander H Knowledge Growth in Medical Education Acad Med, 2001, 76, 669-670