Experts discuss applying systematic review to the field of nutrition

[Guest guest]

Colleagues, the following is FYI and does not necessarily reflect my own

opinion. I have no further knowledge of the topic. If you do not wish to

receive these posts, set your email filter to filter out any messages

coming from @nutritionucanlivewith.com and the program will remove

anything coming from me.

---------------------------------------------------------

Public release date: 2-Dec-2008

http://www.eurekalert.org/pub_releases/2008-12/tuhs-eda120208.php

Contact: Grossman

Tufts University, Health Sciences

Experts discuss applying systematic review to the field of nutrition

Performing systematic reviews of nutrition related topics raises unique

challenges not often encountered in the field of medicine. In a new

article, a team of researchers use specific examples to describe the

steps, strengths, and limitations of systematic reviews relevant to

nutrition and discuss the factors that impact the results.

Systematic reviews, also referred to as evidence-based reviews, provide

objective assessments with pre-specified questions that can be used to

develop clinical and public health practice guidelines, make

recommendations, set research agendas, and formulate scientific

consensus statements.

" Systematic reviews serve as a means of synthesizing and evaluating

evidence from multiple studies in a rigorous and transparent way that

minimizes bias, " says corresponding author Alice H. Lichtenstein, DSc,

director of the Cardiovascular Nutrition Laboratory at the Mayer

USDA Human Nutrition Research Center on Aging (HNRCA) at Tufts

University. " The systematic review approach is flexible and can

accommodate unique challenges posed by questions related to food and

nutrition. "

Writing in the December issue of the Journal of Nutrition, the authors

provide examples illustrating the flexibility of the approach to a wide

range of nutrition-related topics including: effectiveness and safety of

vitamin D in relation to bone health, effects of soy on health outcomes,

and health effects of (n-3) fatty acids on arrythmogenic mechanisms in

animal and isolated organ/cell culture studies.

" When we deal with nutrition-related topics and systematic reviews, we

often address issues that are not encountered in other fields of study, "

says co-author A. Yetley, PhD, a former senior nutrition

research scientist with the National Institutes of Health (NIH).

" Nutrient intake, whether from food or supplements, tends to be more

difficult to accurately quantify than, for example, the daily dosage of

a medication. Therefore, when performing a systematic review, it is

particularly important to document methods of assessment. "

Equally important, the authors write, is the documentation of new data

as it emerges, as well as objectivity. Objectivity of a systematic

review comes from individuals trained in systematic review

methodologies, such as co-author ph Lau, MD, director of the Tufts

Evidence-based Practice Center at the Institute for Clinical Research

and Health Policy Studies at Tufts Medical Center. " To be involved in a

systematic review, I must be free of personal biases or vested interest

in a particular outcome. I focus on the methodology and look to my

colleagues for their nutrition expertise, " says Lau, also a professor at

Tufts University School of Medicine.

The process of performing a systematic review begins with clearly

defining the research question. Lichtenstein, the Stanley N. Gershoff

professor at Tufts' Friedman School of Nutrition Science and Policy, and

colleagues advocate the " PICO " approach to formulating research

questions. The acronym PICO stands for Population (participants),

Intervention (or exposure for observational studies), Comparator and

Outcome. "

" While systematic reviews cannot replace expert judgment and should not

be used as a sole source of information for developing science-based

recommendations and policies, they are valuable tools that can be

adapted effectively for use in the field of nutrition, " says Lichtenstein.

###

This project was funded by the Agency for Healthcare Research and

Quality, U.S. Department of Health and Human Services.

Lichtenstein AH, Yetley EA, Lau J. Journal of Nutrition. December 2008;

Vol 138, Issue 12 . " Application of systematic review methodology to the

field of nutrition. "

Cranney CHT, O'Donnell S, Weiler HA, Ooi DS, Atkinson SA, Ward LM,

Hanley DA, Moher D, Puil L, Fang M, Yazdi F, Garritty C, Sampson M,

Barrowman N, Tsertsvadze A, Mamaladze V. 2007. Agency for Healthcare

Research and Quality. " Effectiveness and safety of vitamin D in relation

to bone health. "

--

ne Holden, MS, RD

" Ask the Parkinson Dietitian " http://www.parkinson.org/

" Eat well, stay well with Parkinson's disease "

" Parkinson's disease: Guidelines for Medical Nutrition Therapy "

http://www.nutritionucanlivewith.com/