Briefing Note - Evidence based practice

Briefing Note - Evidence based practice



This is the third in a series of briefing notes setting out the key differences between dietitians and nutritional therapists (NTs).

Nutritional therapy practice is often attacked for not being 'evidence-based' in contrast to dietetic practice. In fact leading expert dietitians readily admit the lack of evidence underpinning their current practice: the 2007 edition of the BDA Manual of Dietetic Practice, page 134, states:

“Section 1.16.8 Evidence based practice ..In order to be able to access and assess clinical evidence, dietitians must be able to search the literature and have skills in critical appraisal.... They also need to be aware of a major constraint in using an evidence-based approach in dietetics, i.e. the shortage of coherent, consistent scientific evidence for much of dietetic practice.

What dietitians do regard as 'evidence-based' are the national dietary guidelines based on 1991 Department of Health recommendations. However in November 2009 the UK Scientific Advisory Committee on Nutrition published new proposed calorie guidelines after admitting that the 1991 calculations were flawed and inaccurate. This may have huge implications for other recommendations across dietetic practice and food labelling.

In 2009 rapid advances have been made in nutrigenomics/nutrigenetics but as early as 2002 Artemis Simopoulos of the Centre for Genetics, Nutrition and Health in Washington DC said "there may be no such thing as a 'normal' population with respect to nutrient requirements, as was assumed when dietary reference values were established", and "...populations should not copy each other's dietary recommendations for the prevention of coronary artery disease, and cancer, or any other disease for that matter". In 2006 the US Institute of Medicine President Fineberg spoke about the challenge facing the public health paradigm: "It is not just possible but likely that there are nutrients that affect some population groups differently than others, and public health guidelines will have to take such differences into account...A public health paradigm of universal education is going to have to be adapted to the scientific reality and scientific knowledge as it develops and unfolds". And in 2007 experts from the European Food Safety Authority advised that food-based dietary guidelines could not be set at the European level, at most at the national level but even then special groups would have to be considered.

So the answer to the question “Why do nutritional therapists exist if dietetic practice is evidence-based and works?” is that NTs have long-recognised the extent of biochemical individuality and the potential flaws in transferring population guidelines to recommendations for optimising individual health. Public appreciation of NT as effective and meeting individual health goals grows year on year. Put simply, professional advice for optimal health has to take account of unique dietary and nutritional needs – and that is what NTs are trained to give.


Ames, B.N. 2003. The metabolic tune-up: metabolic harmony and disease prevention. Journal of Nutrition 133: 1544S-1548

S. Ames, B.N., Elson-Schwab, I. and Silver, E.A. 2002. High-dose vitamin therapy stimulates variant enzymes with decreased coenzyme binding affinity (increased K(m)): relevance to genetic disease and polymorphisms. American Journal of Clinical Nutrition 75: 616-658.

British Dietetic Association, 2007. Manual of Dietetic Practice

Dept. Health. Dietary reference Values for Food Energy and Nutrients for the United Kingdom (DH, 1991)

European Food Safety Authority. 2007. Food based dietary guidelines. Report of the 5th Scientific Colloquium. Available at: /EFSAScientificColloquiumReports/efsa_locale-1178620753812_FBDG.htm

Fenech, M. 2005. The Genome Health Clinic and Genome Health Nutrigenomics concepts: diagnosis and nutritional treatment of genome and epigenome damage on an individual basis. Mutagenesis 20: 255-269.

SACN, 2009. Draft Energy Requirements Report

Simopoulos, A.P. 2002. Genetic variation and dietary response: nutrigenetics/nutrigenomics. Asia Pacific Journal of Clinical Nutrition 11: 117-128.

Yaktine, A.L. and Pool, R. 2006. Nutrigenomics and beyond: informing the future. National Academies Press, Washington DC, USA.

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