Evidence from dietary patterns is critical to our understanding
of health but more work is needed
by Sarah McNaughton
Dietary intake is a complex exposure, with multiple layers reflecting a continuum from nutrients to foods to eating occasions to overall dietary patterns.Each of these layers, and the interplay between them, are important for health and provide a unique perspective to our understanding of contemporary nutrition problems.
A dietary patterns approach recognises that foods are consumed in complex combinations, that interactions and synergies occur between dietary constituents, and that many health outcomes are multifactorial in nature. Conceptually, dietary patterns examine the combinations, types and amounts of foods consumed in the diet and reflect a measure of total diet.
Dietary patterns are assessed using two main approaches, namely, data driven approaches based on multivariate statistical techniques (e.g. principal component analysis, cluster analysis and reduced rank regression) or investigator–defined patterns commonly based on ‘a priori’ dietary guidelines or recommendations (e.g. diet quality scores). There is now global consensus that food and nutrition policies should be informed by systematically synthesised evidence regarding dietary patterns, and rigorous nutritional epidemiology has a critical role to play in providing this evidence.[2, 3]
Dietary patterns research has developed substantially in the last 15 years and it shows that dietary patterns are important predictors of chronic disease and all-cause mortality. However, there are still significant knowledge gaps. As with studies of individual foods, there is a lack of primary studies for some health outcomes, including mental and neurological health.[5, 6] Some population groups are largely understudied, including children and adolescents, and there is limited data on life-course analyses of dietary patterns and health outcomes. Furthermore, there is a significant lack of published data from low- and middle-income countries. This lack of primary data is a major barrier for the development of dietary guidelines and conducting systematic reviews of dietary patterns evidence.
There are also gaps in knowledge and consensus around fundamental issues relating to methodology. It is important to recognise that each of the approaches to dietary patterns assessment addresses the issue from a different perspective, and the particular method of choice will depend on the research question. A significant challenge facing dietary patterns research is comparability across studies due to different methodological approaches, particularly the data-driven methodologies. This diversity of approaches and their application adds considerable complexity to the synthesis of dietary patterns research that has not yet been acknowledged and addressed. Currently, the conduct and reporting of dietary patterns research is inconsistent and there is a lack of agreed approaches for synthesising evidence generated from dietary patterns studies. Fundamental work to understand the impact of different methodologies, and the development of consensus around use and reporting of primary studies on dietary patterns is required to fully optimise the use of synthesised dietary pattern evidence in the development of dietary guidelines.
Stok, F.M., et al., Dietary Behavior: An Interdisciplinary Conceptual Analysis and Taxonomy. Front Psychol, 2018. 9: p. 1689.
Tapsell, L.C., et al., Foods, Nutrients, and Dietary Patterns: Interconnections and Implications for Dietary Guidelines. Adv Nutr, 2016. 7(3): p. 445-54.
Schulze, M.B., et al., Food based dietary patterns and chronic disease prevention. Bmj, 2018. 361: p. k2396.
Fardet, A. and Y. Boirie, Associations between food and beverage groups and major diet-related chronic diseases: an exhaustive review of pooled/meta-analyses and systematic reviews. Nutr Rev, 2014. 72(12): p. 741-62.
Milte, C.M. and S.A. McNaughton, Dietary patterns and successful ageing: a systematic review. Eur J Nutr, 2016. 55(2): p. 423-50.
Borges, C.A., et al., Dietary patterns: a literature review of the methodological characteristics of the main step of the multivariate analyzes. Rev Bras Epidemiol, 2015. 18(4): p. 837-57.
About the author
Professor Sarah McNaughton is a nutritional epidemiologist and NHMRC Career Development Fellow in the Institute for Physical Activity and Nutrition (IPAN), Deakin University where she leads the Dietary Patterns and Eating Behaviours Research. Her current research includes, understanding population dietary intakes, their determinants, and role in health and wellbeing, and the translation of dietary patterns evidence into nutrition policy and practice.
Recent nutrition reviews in the Cochrane Library
Dietary interventions for adult cancer survivors
Diet has been linked to cancer, and dietary guidelines are available for cancer prevention. People after cancer have been found to have higher rates of other conditions including cardiovascular disease, diabetes, and other cancers. This review included 25 studies and examined evidence on dietary interventions for cancer survivors.
Interventions for increasing fruit and vegetable consumption in children aged five years & under
This review assessed the effectiveness, cost effectiveness and associated adverse events of interventions designed to increase the consumption of fruit, vegetables or both amongst children aged five years and under.
Mediterranean‐style diet for the prevention of cardiovascular disease (CVD)
This review assessed the effects of Mediterranean-style diets for primary prevention of cardiovascular diseases (CVD) among adults at high risk of CVD and for secondary prevention among those with established CVD.
Dietary interventions for induction and maintenance of remission in inflammatory bowel disease (IBD)
This review included 18 RCTs with 1878 participants with active and inactive IBD (ulcerative colitis or Crohn’s disease). Dietary interventions included lowering intake or excluding one or more food groups known to trigger IBD symptoms.
Lifestyle changes in women with polycystic ovary syndrome
This review assessed lifestyle interventions, comprising either a structured physical activity intervention or a combined diet and exercise program, or mindfulness stress management, among women with PCOS.
Iodine fortification of foods and condiments, other than salt, for preventing iodine deficiency disorders
This review included 11 studies with 4317 participants, including school children, women of reproductive age, and infants. Studies used various vehicles for iodine delivery, including biscuits, milk, fish sauce, among others. Daily amounts of iodine provided varied.
This review assessed lifestyle changes for psoriasis including weight reduction, alcohol abstinence, smoking cessation, dietary modification, exercise, among others. Ten trials were included on 1163 participants.
Altering the availability or proximity of food, alcohol, and tobacco products to change their selection and consumption
Of the 24 studies included in this review, most were in laboratory settings and all in high-income settings. Most studies assessed proximity interventions, i.e. distance from food or drink or changing the order of meal components available in a line.
Knowledge translation (KT) in Cochrane is defined as “…the process of supporting the use of health evidence from our high quality, trusted Cochrane systematic reviews by those who need it to make health decisions”. Implementation of KT takes on many forms in Cochrane and includes ‘push’ strategies, designed to distribute evidence to target audiences. Among the many different ways to do this, podcasts are gaining popularity as a communication channel for sharing evidence from research.
Since podcasts are digital audio-only files available to download or stream on-demand using various devices, they are a convenient and time-efficient way to both disseminate and receive evidence. They are easy to consume and allow listeners to stay up-to-date, while offering reviewers an approachable and personal way to share evidence from their review. This can enhance the dissemination of review evidence to non-research audiences.
Cochrane produces podcasts for key reviews. Below we highlight some of these podcasts focusing on nutrition-relevant Cochrane reviews. Click on the links and have a listen!
Effects of nutritional interventions to increase nutritional status in children living in urban slums in low- and middle-income countries
Collaborating with Cochrane Centres to translate nutrition reviews into German
Cochrane Switzerland, Cochrane Germany and Cochrane Austria have partnered in a joint project called Cochrane Kompakt - Unabhängiges Gesundheitswissen für alle/ Informations de santé pour tous (Independent Health Knowledge for All). This project involves translating the plain language summaries of new and updated Cochrane reviews addressing a variety of topics. Recently Cochrane Nutrition worked with these teams to help identify nutrition reviews in Cochrane, from key reviews for translation were then selected. Some summaries were also selected for discussion in their blog, WISSEN WAS WIRKT – Cochrane bloggt auf deutsch (KNOW WHAT WORKS – Cochrane blogs in German)
In 2019, after serving their full term, Advisory Board members, Taryn Young and Tamara Kredo stepped down. We thank them for their invaluable contributions to support establishing Cochrane Nutrition and getting it off the ground during the initial few years. A special thank you also to Mark Lawrence for serving as Chair for his first term. We are very pleased to announce that Chizuru Nishida has taken over as our newly elected Advisory Board Chair.
A very warm welcome and thanks to four new Advisory Board members who joined in October 2019.
Betsy Kristjansson, Co-chair and Editor, Nutrition group, Campbell Collaboration; Associate Professor, Faculty of Social Sciences, University of Ottawa, Canada
Natalia Elorriaga, Researcher, Center of Excellence in Cardiovascular Health for South America (CESCAS) of the Institute of Clinical Healthcare Effectiveness (IECS)
Vivian Welch, Editor in Chief, Campbell Collaboration; Director of Methods, Bruyère Research Institute, and Assistant Professor, School of Epidemiology and Public Health, University of Ottawa, Canada
Lee Hooper, Content Editor, Cochrane Heart; Reader in Research Synthesis, Nutrition & Hydration, Norwich Medical School, United Kingdom
Cochrane Santiago Colloquium 2019 –
the first virtual Colloquium
Cochrane’s annual flagship event brings together the world’s most influential health researchers, scientists, academics, opinion leaders, clinicians, and patients to promote evidence-informed decision-making. This year the Colloquium was to take place in Santiago, Chile, but unfortunately had to be cancelled due to an unprecedented situation of civil unrest. Despite this, the organizers planned and hosted a spectacular Virtual #CochraneSantiago from 2 – 6 December 2019 that featured much of the content accepted for the live event. The virtual event was free and open to everyone.
Cochrane Nutrition participated in the Virtual #CochraneSantiago event by contributing a:
digital poster, titled Accessible Cochrane nutrition evidence: ‘packaging and push’ and ‘facilitating pull’ in action, which showcased some of Cochrane Nutrition’s KT products and activities aimed at implementing the ‘packaging, push and support to implementation’ and ‘facilitating pull’ themes of Cochrane’s KT framework. See the poster
long oral presentation video to share our approach, experiences and lessons learned in collaborating to respond timeously to a policymaker request for a published priority nutrition review, titled 'To fast or not to fast': Cochrane Nutrition and the Cochrane Fast-track Service join hands to produce a priority nutrition review for WHO. Watch the video