Abstract
Background
It is unclear whether diet affects glycaemic control in type 2 diabetes (T2D), over and above its effects on bodyweight. We aimed to assess whether changes in dietary patterns altered glycaemic control independently of effects on bodyweight in newly diagnosed T2D.
Methods
We used data from 4-day food diaries, HbA1c and potential confounders in participants of the Early-ACTivity-In-Diabetes trial measured at 0, 6 and 12 months. At baseline, a ‘carb/fat balance’ dietary pattern and an ‘obesogenic’ dietary pattern were derived using reduced-rank regression, based on hypothesised nutrient-mediated mechanisms linking dietary intake to glycaemia directly or via obesity. Relationships between 0 and 6 month change in dietary pattern scores and baseline-adjusted HbA1c at 6 months (n = 242; primary outcome) were assessed using multivariable linear regression. Models were repeated for periods 6–12 months and 0–12 months (n = 194 and n = 214 respectively; secondary outcomes).
Results
Reductions over 0–6 months were observed in mean bodyweight (− 2.3 (95% CI: − 2.7, − 1.8) kg), body mass index (− 0.8 (− 0.9, − 0.6) kg/m2), energy intake (− 788 (− 953, − 624) kJ/day), and HbA1c (− 1.6 (− 2.6, -0.6) mmol/mol). Weight loss strongly associated with lower HbA1c at 0–6 months (β = − 0.70 [95% CI − 0.95, − 0.45] mmol/mol/kg lost). Average fat and carbohydrate intakes changed to be more in-line with UK healthy eating guidelines between 0 and 6 months. Dietary patterns shifting carbohydrate intakes higher and fat intakes lower were characterised by greater consumption of fresh fruit, low-fat milk and boiled/baked potatoes and eating less of higher-fat processed meats, butter/animal fats and red meat. Increases in standardised ‘carb/fat balance’ dietary pattern score associated with improvements in HbA1c at 6 months independent of weight loss (β = − 1.54 [− 2.96, − 0.13] mmol/mol/SD). No evidence of association with HbA1c was found for this dietary pattern at other time-periods. Decreases in ‘obesogenic’ dietary pattern score were associated with weight loss (β = − 0.77 [− 1.31, − 0.23] kg/SD) but not independently with HbA1c during any period.
Conclusions
Promoting weight loss should remain the primary nutritional strategy for improving glycaemic control in early T2D. However, improving dietary patterns to bring carbohydrate and fat intakes closer to UK guidelines may provide small, additional improvements in glycaemic control.
It is unclear whether diet affects glycaemic control in type 2 diabetes (T2D), over and above its effects on bodyweight. We aimed to assess whether changes in dietary patterns altered glycaemic control independently of effects on bodyweight in newly diagnosed T2D.
Methods
We used data from 4-day food diaries, HbA1c and potential confounders in participants of the Early-ACTivity-In-Diabetes trial measured at 0, 6 and 12 months. At baseline, a ‘carb/fat balance’ dietary pattern and an ‘obesogenic’ dietary pattern were derived using reduced-rank regression, based on hypothesised nutrient-mediated mechanisms linking dietary intake to glycaemia directly or via obesity. Relationships between 0 and 6 month change in dietary pattern scores and baseline-adjusted HbA1c at 6 months (n = 242; primary outcome) were assessed using multivariable linear regression. Models were repeated for periods 6–12 months and 0–12 months (n = 194 and n = 214 respectively; secondary outcomes).
Results
Reductions over 0–6 months were observed in mean bodyweight (− 2.3 (95% CI: − 2.7, − 1.8) kg), body mass index (− 0.8 (− 0.9, − 0.6) kg/m2), energy intake (− 788 (− 953, − 624) kJ/day), and HbA1c (− 1.6 (− 2.6, -0.6) mmol/mol). Weight loss strongly associated with lower HbA1c at 0–6 months (β = − 0.70 [95% CI − 0.95, − 0.45] mmol/mol/kg lost). Average fat and carbohydrate intakes changed to be more in-line with UK healthy eating guidelines between 0 and 6 months. Dietary patterns shifting carbohydrate intakes higher and fat intakes lower were characterised by greater consumption of fresh fruit, low-fat milk and boiled/baked potatoes and eating less of higher-fat processed meats, butter/animal fats and red meat. Increases in standardised ‘carb/fat balance’ dietary pattern score associated with improvements in HbA1c at 6 months independent of weight loss (β = − 1.54 [− 2.96, − 0.13] mmol/mol/SD). No evidence of association with HbA1c was found for this dietary pattern at other time-periods. Decreases in ‘obesogenic’ dietary pattern score were associated with weight loss (β = − 0.77 [− 1.31, − 0.23] kg/SD) but not independently with HbA1c during any period.
Conclusions
Promoting weight loss should remain the primary nutritional strategy for improving glycaemic control in early T2D. However, improving dietary patterns to bring carbohydrate and fat intakes closer to UK guidelines may provide small, additional improvements in glycaemic control.
| Original language | English |
|---|---|
| Article number | 161 |
| Number of pages | 12 |
| Journal | BMC Medicine |
| Volume | 20 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 18 Apr 2022 |
Bibliographical note
Funding Information:The authors acknowledge the participants in the Early-ACTID trial, members of the Early-ACTID team and steering committee, S.J. MacNeill (Bristol Medical School, University of Bristol, UK) for her advice on statistical analysis and S. Khodabakhsh (Exercise, Nutrition and Health Sciences (ENHS), School for Policy Studies, University of Bristol, UK) for her assistance with food diary coding.
Funding Information:
This work was supported in part by grant MR/N0137941/1 for the GW4 BIOMED MRC DTP, awarded to the Universities of Bath, Bristol, Cardiff and Exeter from the Medical Research Council (MRC)/UKRI. The Early-Activity-In-Diabetes trial was supported by Diabetes UK, the UK Department of Health and Western Comprehensive Local Research Network. Dietary analysis was supported by the Above and Beyond Foundation and the National Institute for Health Research. AGJ was supported by an NIHR Clinician Scientist award (CS-2015-15-018). The study sponsors/funders were not involved in the design of the study; the collection, analysis and interpretation of data; writing the article; and did not impose any restrictions regarding the publication of this article.
Publisher Copyright:
© 2022, The Author(s).
Research Groups and Themes
- SPS Exercise, Nutrition and Health Sciences
Keywords
- HbA1c
- Type 2 diabetes
- Diet
- Dietary patterns
- Reduced rank regression
- Carbohydrates
- Fat
- Fibre
- Energy-density
- Weight loss
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Dietary patterns and progression of Type 2 Diabetes
Garbutt, J. D. W. (Author), England, C. Y. (Supervisor), Salway, R. E. (Supervisor), Johnson, L. (Supervisor), Andrews, R. (Supervisor) & Jones, A. (Supervisor), 24 Jan 2023Student thesis: Doctoral Thesis › Doctor of Philosophy (PhD)
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Datasets
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Early-ACTID dietary pattern data
Garbutt, J. (Creator) & Johnson, L. (Data Manager), University of Bristol, 8 Sept 2021
DOI: 10.5523/bris.3o7bip8v2ae8m2gdfpu1pt5rlz, http://data.bris.ac.uk/data/dataset/3o7bip8v2ae8m2gdfpu1pt5rlz
Dataset