ReviewDietary intake by food group of individuals with type 2 diabetes mellitus: A systematic review
Introduction
Diabetes is a leading global health emergency estimated to cost US$827 billion per year [1]. In 2015 it was estimated that 415 million adults were living with diabetes worldwide, with 90–95% living with type 2 diabetes mellitus (T2DM) [1], [2]. Most of the burden of T2DM is attributed to macro- and micro-vascular complications, and co-morbidities such as cardiovascular disease; many of which are associated with sub-optimal glycaemic control [3]. Effective glycaemic control can help to prevent or delay such complications and co-morbidities [4]. Strategies to assist individuals to optimize glycaemic control to reduce the individual and economic burden associated with T2DM are urgently required.
Dietary intake is well recognized as influencing glycaemic control [5]. Recommendations to manage T2DM include eating healthy foods to have a high-quality diet [6], [7]. A randomized controlled trial (RCT) conducted in New Zealand that provided healthy foods to a group of individuals (n = 53) with T2DM, saw reductions in HbA1c of 0.4% [8]. A cohort study conducted in the United States (US) showed that individuals (n = 234) with T2DM who followed a healthy diet for 12 months experienced improved HbA1c levels of 0.54% [9]. Clearly, having a healthy diet can improve glycaemic control [8], [9].
A variety of different dietary patterns have been shown to be effective at improving glycaemic control in individuals with T2DM [10], [11]. Assessing dietary intake using dietary patterns based on foods and food groups has become increasingly common in nutritional epidemiology studies [12]. This approach provides a more accurate representation of dietary intake than analysing intake of specific nutrients (e.g. carbohydrate) or dietary constituents (e.g. fibre), that are generally not consumed in isolation [13]. Improvements in diet based on foods and food groups have shown stronger and more consistent associations with reduced risk of adverse health outcomes, compared with improvements of specific nutrients [14]. A systematic review and meta-analysis of 20 RCTs compared the following dietary patterns: low-carbohydrate, high-carbohydrate, Mediterranean, low glycaemic-index, high-protein, vegan and vegetarian, and high-fibre to controls for six months or more in individuals with T2DM [10]. Results showed the low-carbohydrate, Mediterranean, low-glycaemic-index and high-protein diets all led to greater improvements in HbA1c than their respective control diets [10]. While these diets have some differing characteristics, they all encourage consuming unprocessed foods from the five food groups; fruit, vegetables, grains, dairy, and meat/meat alternatives. As a result, management guidelines from several countries recommend that individuals with T2DM adhere to national dietary guidelines expressed in terms of the five food groups [6], [7], [15].
The actual food group intake of individuals with T2DM after diagnosis is currently unclear. Evaluating dietary intake is recognized as an important research activity that can help influence dietary education materials and target nutritional interventions [16]. The purpose of this systematic review was to synthesize and evaluate the peer-reviewed literature that investigates the dietary intake by food group of individuals diagnosed with T2DM and compare intakes to national and international guidelines.
Section snippets
Methods
A systematic review of peer-reviewed observational studies investigating the food group intake of individuals diagnosed with T2DM was conducted. The review was registered with the International Prospective Register of Systematic Reviews, PROSPERO (Registration ID: CRD42017074756). The systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) checklist. The PRISMA flow diagram (Fig. 1) has been included to document the
Results
The search identified 13,662 unique publications, from which 120 full-text articles were retrieved. Eleven publications met the criteria for inclusion in the final review (see Fig. 1). The most common reason for excluding studies was a lack of applicable outcomes. For example, many studies reported the dietary intake of participants using macronutrients (carbohydrate, protein and fat) rather than food groups [21]. Other studies analysed the intake of only one food group rather than all five,
Discussion
This systematic review provides the first synthesis of the peer-reviewed literature on the food group intake of individuals diagnosed with T2DM. The findings suggest individuals do not adhere to national food group recommendations. However, majority of studies met the minimum daily gram recommendation for fruit and vegetables outlined by the WHO. This review highlights several methodological issues for future research on this topic.
Of the six studies that assessed intake by daily food group
Conclusion
This review synthesized literature that investigated the food group intake of individuals with T2DM. Individuals with T2DM appear to consume insufficient amounts of fruit, vegetables, dairy and grains. Future longitudinal research is required to examine the relationship of time from diagnosis with food group intake to facilitate targeted and effective strategies that enhance glycaemic control in this population.
Acknowledgements
None.
Funding
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Conflict of interest statement
The authors declare no conflicts of interest.
Authors contributions
EB, LW, and LB designed the research; all authors conducted the research and analysed the data and EB, LW and LB wrote the paper. All authors had primary responsibility for final content. All authors read and approved the final manuscript.
References (58)
- et al.
Systematic review and meta-analysis of different dietary approaches to the management of type 2 diabetes
Am J Clin Nutr
(2013) - et al.
Prevention and management of type 2 diabetes: dietary components and nutritional strategies
Lancet
(2014) - et al.
Dietary patterns: from nutritional epidemiologic analysis to national guidelines
Am J Clin Nutr
(2015) - et al.
Tracking nutrient changes for trends analysis in the United States
J Food Comp Anal
(2001) - et al.
Habitual chocolate intake and type 2 diabetes in the maine-syracuse longitudinal study: (1975–2010): prospective observations
Appetite
(2017) - et al.
Action for health in diabetes (Look AHEAD) trial: baseline evaluation of selected nutrients and food group intake
J Am Diet Assoc
(2009) - et al.
Sex differences in food choices, adherence to dietary recommendations and plasma lipid profile in type 2 diabetes – The TOSCA.IT study
Nutr Metab Cardiovasc Dis
(2016) - et al.
Relationship of diet quality to food security and nutrition knowledge in low-income, community-dwelling elders with type 2 diabetes: a pilot study
Can J Diab
(2012) - et al.
Can diet prevent diabetes?
J Diab Complicat
(2017) - International Diabetes Federation (IDF). IDF diabetes atlas. United Kingdom: IDF;...
Diabetes and cardiovascular disease: epidemiology, biological mechanisms, treatment recommendations and future research
World J Diab
Association of glycaemia with macrovascular and microvascular complications of type 2 diabetes (UKPDS 35): prospective observational study
BMJ
Academy of nutrition and dietetics nutrition practice guideline for Type 1 and Type 2 diabetes in adults: systematic review of evidence for medical nutrition therapy effectiveness and recommendations for integration into the nutrition care process
J Acad Nutr Diet
Diabetes UK evidence-based nutrition guidelines for the prevention and management of diabetes
Diab Med
Canadian Diabetes Association 2013 clinical practice guidelines for the prevention and management of diabetes in Canada
Can J Diab
Nutritional intervention in patients with type 2 diabetes who are hyperglycaemic despite optimised drug treatment—Lifestyle Over and Above Drugs in Diabetes (LOADD) study: randomised controlled trial
BMJ
Glycaemic control and self-management behaviours in type 2 diabetes: results from a 1-year longitudinal cohort study
Diab Med
Using two different approaches to assess dietary patterns: hypothesis-driven and data-driven analysis
Nutrients
Associations between food and beverage groups and major diet-related chronic diseases: an exhaustive review of pooled/meta-analyses and systematic reviews
Nutr Rev
Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement
PLoS Med
Now and then: the global nutrition transition: the pandemic of obesity in developing countries
Nutr Rev
Mixed kinds of evidence: synthesis designs and critical appraisal for systematic mixed studies reviews including qualitative, quantitative and mixed methods studies
Evid Based Med
Diabetes-related nutrition knowledge and dietary intake among adults with type 2 diabetes
Br J Nutr
Self-care behaviors of adults with type 2 diabetes in Greece
J Commun Health
Dietary intake in Japanese patients with type 2 diabetes: analysis from Japan diabetes complications study
J Diab Invest
Cited by (22)
Analyzing Dietary Behaviors Self-reported by People With Diabetes Using a Behavior Change Technique Taxonomy
2022, Journal of Nutrition Education and BehaviorCitation Excerpt :Dietitians are well placed for embedding psychological and behavioral theories within their consultations to support dietary behavior change leading to improved health outcomes.4,5 Evidence from a systematic review showed that people with T2D did not meet their national food-based dietary group recommendations.6 The early stage of T2D presents a key area of management to reduce the progression of the illness.2
AGP and Nutrition – Analysing postprandial glucose courses with CGM
2021, Diabetes Research and Clinical PracticeCitation Excerpt :They can not only help people to improve their understanding of their own diet and individual glucose levels, the Academy of Nutrition and Dietetics has also published a systematic review showing that nutritional therapies can significantly improve the quality of life of people with T1D and T2D [13]. Nutritional therapies can change the food intake, but it is difficult for people to keep following a change in their eating habits [14,15]. This often seems to be due to the challenges of managing restrictions, appetite and social factors [16,17].
Perspective: The Role of Beverages as a Source of Nutrients and Phytonutrients
2020, Advances in Nutrition