Abstract
Aim:
The aim of the study is to gain insights into the relationship between diabetes-related nutrition knowledge (DRNK) and diet quality in Singapore.
Methods:
Forty-two participants were recruited from a tertiary hospital. DRNK and diet quality were ascertained with the DRNK questionnaire and Alternate Healthy Eating Index 2010, respectively. Twenty-one semi-structured interviews of perceived barriers and enablers to adherence to dietary guidelines were audio recorded, transcribed and analysed.
Results:
Participants had a poor mean percentage DRNK score of 39.7% (±17.7) and diet quality of 54.2% (±9.4). Pearson’s correlation tests revealed no correlation between DRNK and diet quality (
Conclusion:
DRNK may not correlate with adherence to dietary guidelines; multiple mediating factors are identified when translating DRNK to practice.
Introduction
The rising prevalence of type 2 diabetes mellitus (T2DM) is an international concern, with Asia identified as an emerging epicentre of this global epidemic. 1 In Singapore, this has been forecasted to double from 7.3% in 1990 to 15% in 2050, with concomitant implications for increased healthcare expenditure. 2 Despite pharmacotherapy advances, interventions targeting lifestyle changes such as medical nutrition therapy (MNT) and diabetes self-management education (DSME) remain the cornerstones in T2DM management.3,4 Recent studies continue to demonstrate that patients with T2DM who received and adhered to MNT and DSME had improvements in anthropometric and biomedical markers relevant to disease outcomes.5,6
One of the common dietary goals in providing MNT and DSME is to improve diabetes-related nutrition knowledge (DRNK) to facilitate positive dietary practices and augment diet quality. Having knowledge about dietary management in T2DM may strongly influence food selection and dietary behaviours. 7 Studies have shown that provision of nutrition education can improve DRNK and dietary practices in patients with T2DM.8-9 Diabetes knowledge (including diet-related) is also highly correlated to better psychosocial self-efficacy, a strong predictor for behavioural intention and dietary behaviours in patients with T2DM. 10 A typical MNT consult to a patient with T2DM in the clinic/ward setting is a one-on-one therapy session, lasting between 30 and 45 minutes. The frequency and content of sessions is patient dependent and guided by local dietetics department protocols and national evidence best practice guidelines. Individualising the MNT consults is part of current practice, and the dietitian will tailor their counselling to address knowledge deficits or enablers and barriers towards its application.
While imparting DRNK is fundamental in dietary interventions, the MNT is not complete without the translation of knowledge to practice (adherence to dietary guidelines). Assessment of such adherence can be measured with a diet quality index – as an indicator of adherence to dietary guidelines/evidence-based dietary recommendations. 11 A higher diet quality has also been associated with reduced risk of all-cause mortality and 10-year predicted cardiovascular disease in patients with T2DM.12,13 Other than DRNK, there are other factors affecting the adherence to dietary guidelines. Patients with T2DM are faced with situational obstacles when it comes to selection of food on a daily basis. 14 Previous studies have identified time constraints, cost and lack of social support to be some examples of barriers to adherence to dietary recommendations.15,16
Despite being important components in the dietary management of T2DM, there is a dearth of research investigating factors affecting adherence to dietary guidelines in patients with T2DM. It is unclear whether better DRNK is associated with closer adherence to dietary guidelines. Our study aimed to (1) explore the correlation between DRNK and adherence to dietary guidelines, if any, and (2) describe enablers and barriers to dietary adherence in T2DM patients in Singapore.
Methods
We employed an embedded quantitative dominant, mixed-methods approach to this exploratory study. 17 The quantitative and qualitative part of the study are reported in accordance to the Strengthening the Reporting of Observational studies in Epidemiology – Nutritional Epidemiology (STROBE-nut) and the COnsolidated criteria for REporting Qualitative (COREQ) research statement, respectively.18,19 The study was approved by the National Healthcare Group Domain specific review board Reference: 2017/00941, and conducted according to the tenets of the Declaration of Helsinki. Recruited participants received information about anonymity and confidentiality, consented to take part in the study and retained a written copy of the information sheet.
Purposive sampling was employed to recruit adult T2DM patients with dietary self-management issues. These are patients referred to a dietitian for MNT as deemed necessary by their attending physician. Only participants who were literate in English were included, as the research tools/methods (surveys and interviews) were neither available nor conducted in other languages. Patients with kidney diseases, type 1 diabetes and/or who were pregnant were excluded from the study, as they were not the focus of this study. Patients with cognitive impairment were also excluded, as the diabetes-related nutrition knowledge questionnaire (DRNK-Q) is a test of knowledge.
We used a locally validated tool, the DRNK-Q, to assess the level of DRNK in our cohort. 20 The DRNK-Q consists of four sections and 27 questions related to the topics covered in dietetic therapy and education sessions for patients with T2DM: food portion and sizes; nutrition content of food; healthier food choices and safety; and food label reading. The DRNK-Q was completed before the patients were provided with further dietary advice to prevent contamination of results.
Dietary data were derived from diet histories (7-day typical food intake is reported with a checklist of food consumed using an in-depth interview style by dietitians) collected from the participant’s respective attending dietitians who performed routine dietary assessment prior to their MNT. 21 These diet histories were analysed with nutrient analyses software (FoodWorks 9 Professional), a local food composition database and food labels. 22 To ensure integrity of the dietary data, we measured the ratio of individual energy intake (EI) to basal metabolic rate (BMR) using the method as described by Goldberg et al. 23 BMR was estimated with the Harris Benedict equation, consistent with the institution’s energy estimation method for T2DM patients. 24
We measured degree of adherence to dietary guidelines with the Alternate Healthy Eating Index (AHEI-2010) as its components are closest to diet recommendations for individuals with T2DM in Singapore.25,26 The AHEI-2010 consists of 11 components, with score ranging 0–110. It includes six components addressing quantity and quality (vegetables; fruit; whole grains; nuts and legumes; long chain fats, percentage polyunsaturated fatty acids) and five components addressing items to be taken in moderation (sugar-sweetened beverages and fruit juice; red/processed meat; trans-fat; sodium; alcohol). 27 Higher scores on the AHEI-2010 reflect closer adherence to dietary guidelines, indicative of better overall diet quality. We modified the scoring for sodium component by using consumption data from our national nutrition survey. 28 We also used the adapted alcohol recommendation (<1 drink a day) as it is more culturally appropriate. 29 Participants’ gender, age, ethnicity, weight, height, income, education, length of diabetes diagnosis, marital status and psychosocial self-efficacy (using the diabetes empowerment scale short-form) were also surveyed. 30
To explore the factors affecting adherence to dietary guidelines, in-depth individual interviews were conducted to allow participants to freely express their personal views. Interviews were conducted with curtains drawn if at patient’s bedside, or in private rooms to ensure privacy.
C.G.C. (Senior Psychologist, PhD, second author) is a trained psychologist with expertise in management of patients with T2DM. Other than experience of delivering MNT to patients with T2DM, C.Y.H. (Senior Dietitian, first author) received training in mixed-methods research before this study. They jointly prepared two open-ended questions that aimed to encourage participants to share in-depth experiences and thoughts: (1) What are some factors that have helped you apply your nutrition knowledge to actual practice?; (2) What are some difficulties that you face when trying to apply what you have learnt about diabetes and food into your daily life? Verbal prompts were used only when participants did not spontaneously raise key issues related to the questions. C.Y.H. conducted training sessions with Z.W.W. and Y.T.C. (dietetic interns) on administering of the interviews. Both interviewers are not involved with the direct care/MNT or had any prior professional contact with those enrolled. The interviews were audio recorded with a recorder model Olympus VP-10 and transcribed verbatim. Transcription was done by Y.T.C. and vetted by C.Y.H.. A thematic analysis approach, vetted by C.G.C., was used to examine the content of the aforementioned interviews. Coding of the key and recurring ideas in the transcripts were described and recorded. Any coding discrepancies were resolved through a discussion with the research team until a consensus was reached. Themes and subthemes were derived from the data solely and none were identified in advance. Interviews continued until data saturation was reached, where the interviewers reported to the researcher that the same comments are being heard repeatedly (information redundancy).
All analyses were performed using SPSS version 21.0 (IBM corp). Two-sided
Results
Out of 164 potential participants screened, 47 were recruited, and 42 and 21 were analysed for quantitative and qualitative components, respectively (Figure 1). Participants (

Recruitment flowchart.
Analyses of participants’ demographics and characteristics by % diabetes-related nutrition knowledge (DRNK) score.
DRNK score range: lower 4–41; higher 44–78.
Analyses of dietary characteristics by % diabetes-related nutrition knowledge (DRNK) score.
DRNK score range: lower 4–41; higher 44–78.
Sample quotes from qualitative interviews by theme.
Participants in our cohort (
Independent sample
The average total daily EI, percentage of energy contribution from carbohydrate, protein and fat was 2028±1070 kcal, 50±9%, 17±5% and 32±7%, respectively. The mean overall diet quality score in our cohort (
With reference to Table 2, participants belonging to the higher DRNK group tended to have lesser total energy, carbohydrate and sugar intake from their diets on average, though the differences did not reach a statistical significance. On contrary, participants in the higher DRNK group averaged a significantly lower diet quality as ascertained by the AHEI-2010 (
From the interviews, participants often felt that their environment offered limited healthier food choices (
The lack of motivation to change current habits (
The differences in participants’ perception of time (
Participants reported that pressure from family members to maintain a ‘diabetic diet’ was often perceived as stressful (
Participants reported that the lack of DRNK (
In terms of enablers to healthy eating, participants perceived that support from healthcare professionals (
Participants claimed that the presence of personal motivation, through feelings of individual responsibility towards managing T2DM (
Discussion
This is the first study to report on DRNK levels and factors affecting adherence to dietary guidelines in Singapore. Other than an overall poor DRNK and diet quality, we found a moderate positive correlation between DRNK and psychosocial self-efficacy and identified factors affecting DRNK and adherence to dietary guidelines.
Our cohort had a lower mean DRNK as compared with a recent similar study that found mean DRNK to be 59.2±16.4%. 24 This could be due to a higher proportion of lower socio-economic class participants in our study (48% vs. 31%), as socio-economic status has an impact on nutrition knowledge. 31 Participants fared worst in the knowledge area on food portions and healthier food choices. During education, pictorial and teach back methods can be implemented routinely for those with a lower level of educational attainment. 32
The moderate positive correlation between DRNK and self-efficacy in our cohort is similar to another study in India (
We observed fair diet quality scores in our cohort similar to other studies reporting scores ranging from 40.2 to 58.8, with poor intake of wholegrains, dairy, fruits and vegetables.34,35 In Singapore, the promotion of wholegrains, fruits and vegetables is ubiquitous among public diabetes-related health messages, guidelines and education. 26 However, our findings suggest that these health promotional messages may not necessarily be translated into ‘process knowledge’ in patients with T2DM. 36 Previously studies have shown a weak positive relationship between nutrition knowledge and diet quality in the general population.37,38 The lack of correlation between DRNK and diet quality in our cohort of patients with T2DM suggests the influence of mediating factors between them.
Our qualitative data provided insights to possible mediators between DRNK and diet quality, lending support to our conceptual framework describing local factors affecting adherence to dietary guidelines in patients with T2DM (Figure 2). Cumulatively, the perceptions of barriers towards adherence to dietary guidelines were mostly extrinsic. There was an overarching sentiment that an obesogenic environment was the key reason. It is well known that the built and workplace environments play a substantial role in dietary practices and prevention of obesity.38,39 In addition, we found digital social media to be a part of these environments promoting unhealthier food choices and hindering adherence to healthier food choices.

Conceptual framework of diabetes-related nutrition knowledge, barriers and enablers to adherence to dietary guidelines in Singaporean patients with Type 2 Diabetes.
Participants also identified having a busy work schedule as a barrier towards adherence to dietary recommendations, which resulted in prioritising satiety over recommended ‘acceptable food’.40-41 Some participants reported resentment towards their family and friends’ ‘over-controlling’ behaviour on their diet, isolating them by disallowing participation in consumption of certain communal food at social events. While social support can foster positivity towards diabetes self-care activities, an opposite effect can arise from such negative social interactions. 42
The burden of diabetes-related expenses such as medication was also reported to compete with perceived financial costs associated with healthy eating. A local study revealed that the diabetes-related medical cost in Singapore (USD1575.6 per annum per patient) was indeed higher than other Asian countries. 43
While patients can be motivated through a sense of responsibility towards T2DM and recognition of importance of diet in diabetes self-care, the lack of it was identified as a barrier to improving eating habits. 44
In coherence with having poor DRNK on average, some participants described trouble processing or recalling information provided to them. Inadequate understanding of the diet–disease link has been a long-standing barrier towards adherence to dietary guidelines. 16 The differences in perspectives between dietary advice and what participants were able to accept or change may also give rise to negative connotations towards diet adherence. 44 Therefore, individualised DRNK education sessions play a vital role to synthesise old and new knowledge to help improve compliance to dietary recommendations and MNT.45-46 Time spent with healthcare professionals may have a far-reaching effect on diet adherence. Relationship and trust between healthcare providers and patients have been associated with improved adherence to diabetes self-care practices.47,48
The present exploratory study has several strengths. The use of a locally validated questionnaire ensured cultural appropriateness and accuracy when assessing DRNK. The purposive sampling method allowed us to recruit from our population of interest, gaining new insights to the issue surrounding a common group of acute care patients. However, our results are not without limitations. We recognise that the dietary data collected can be affected by acute events and change in appetite leading to the participant’s acute care admission. However, this was taken into consideration as patients referred for poor oral intake were excluded in our study. The small sample size collected from a single institution also limits the generalisability of our results. We consolidated themes from our results and created the
Conclusion
We identified factors, including DRNK, mediating adherence to dietary guidelines. Though DRNK is fundamental to individuals with T2DM, dietary counselling for patients with T2DM goes beyond a one-off nutrition education session. It is important to enforce follow-up dietitian sessions to explore facilitators and barriers towards translating DRNK into practice. Consequently, there is a role for dietitians to empower patients with T2DM beyond increasing DRNK. The BE-2-HE checklist could facilitate dietary counselling by helping patients with T2DM self-identify factors affecting adherence to dietary guidelines before seeing their healthcare practitioners. However, further detailed research is suggested to validate and ascertain its usefulness.
Supplemental Material
Appendix_1_Overall_cohort_vs_qualitative – Supplemental material for Diabetes-related nutrition knowledge and dietary adherence in patients with Type 2 diabetes mellitus: A mixed-methods exploratory study
Supplemental material, Appendix_1_Overall_cohort_vs_qualitative for Diabetes-related nutrition knowledge and dietary adherence in patients with Type 2 diabetes mellitus: A mixed-methods exploratory study by Chad Yixian Han, Cherie Geok Boon Chan, Su Lin Lim, Xiaomei Zheng, Zhing Wen Woon, York Thong Chan, Kalpana Bhaskaran, Kim Fong Tan, Kejendran Mangaikarasu and Mary Foong-Fong Chong in Proceedings of Singapore Healthcare
Supplemental Material
Appendix_2_BE-2-HE_all_4_languages – Supplemental material for Diabetes-related nutrition knowledge and dietary adherence in patients with Type 2 diabetes mellitus: A mixed-methods exploratory study
Supplemental material, Appendix_2_BE-2-HE_all_4_languages for Diabetes-related nutrition knowledge and dietary adherence in patients with Type 2 diabetes mellitus: A mixed-methods exploratory study by Chad Yixian Han, Cherie Geok Boon Chan, Su Lin Lim, Xiaomei Zheng, Zhing Wen Woon, York Thong Chan, Kalpana Bhaskaran, Kim Fong Tan, Kejendran Mangaikarasu and Mary Foong-Fong Chong in Proceedings of Singapore Healthcare
Footnotes
Acknowledgements
The authors would like to acknowledge the kind approval of Dr Martha Funnell of Michigan Diabetes Research Centre for the use of the DES-SF questionnaire. The investigators would also like to thank Singapore polytechnic and Dietetics Department, Ng Teng Fong General Hospital for the support in collection of data.
Author Declaration
I, C.Y.H., hereby certify that the manuscript that I am submitting on behalf of all authors is entirely original, where otherwise indicated. I am aware of the journal’s regulations concerning plagiarism, including those regulations concerning disciplinary actions that may result from plagiarism. Any use of the works of any other author, in any form, is properly acknowledged at their point of use.
Authors’ contributions
C.Y.H. and M.F.C. conceived of the presented idea, developed the theory and study design. C.Y.H., X.M., Y.T.C., Z.W.W. carried out the project, while K.B. and M.F.C. supervised. C.Y.H. C.G.C., K.M., K.F.T., K.B., M.F.C. and S.L.L contributed to the interpretation of the results. C.Y.H. took the lead in writing the manuscript. All authors provided critical feedback and helped shape the research, analysis and manuscript.
Availability of data
Upon reader’s request and approval from the NHG domain specific ethics review board.
Ethical approval
The study was approved by the Domain specific review board (NHG DSRB Reference: 2017/0094).
Informed Consent
Informed consent was provided by all participants.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
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References
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