Advice to follow a low-carbohydrate diet has a favourable impact on low-grade inflammation in type 2 diabetes compared with advice to follow a low-fat diet

Abstract

Background Inflammation may play an important role in type 2 diabetes. It has been proposed that dietary strategies can modulate inflammatory activity.Methods We investigated the effects of diet on inflammation in type 2 diabetes by comparing a traditional low-fat diet (LFD) with a low-carbohydrate diet (LCD). Patients with type 2 diabetes were randomized to follow either LFD aiming for 55–60 energy per cent (E%) from carbohydrates (n = 30) or LCD aiming for 20 E% from carbohydrates (n = 29). Plasma was collected at baseline and after 6 months. C-reactive protein (CRP), interleukin-1 receptor antagonist (IL-1Ra), IL-6, tumour necrosis factor receptor (TNFR) 1 and TNFR2 were determined.Results Both LFD and LCD led to similar reductions in body weight, while beneficial effects on glycaemic control were observed in the LCD group only. After 6 months, the levels of IL-1Ra and IL-6 were significantly lower in the LCD group than in the LFD group, 978 (664–1385) versus 1216 (974–1822) pg/mL and 2.15 (1.65–4.27) versus 3.39 (2.25–4.79) pg/mL, both P < 0.05.Conclusions To conclude, advice to follow LCD or LFD had similar effects on weight reduction while effects on inflammation differed. Only LCD was found significantly to improve the subclinical inflammatory state in type 2 diabetes.

Carbohydrate restriction for glycaemic control in Type 2 diabetes: a systematic review and meta‐analysis

“…Significant between‐group differences in HbA 1c were observed in six of the 25 RCTs . Some studies reported significant differences at 6 months which were not maintained at 12 months and beyond . Meta‐analyses conducted for HbA 1c for all studies found no overall effect of modifying carbohydrate and demonstrated a high level of heterogeneity [WMD –0.09% (95% CI –0.27, 0.08; P = 0.30); I 2 72% ( P <0.001); Fig.…”

“… Where separate baseline values are not reported, the entire cohort values are used for both groups. Additional data received directly from authors: Dyson, 2007 , Larsen, 2011 , Jonasson, 2014 , Ben‐Avraham, 2009 . …”

“…Participant bias and the Hawthorne effect are also likely in dietary intervention trials and may be evident in studies in the present review, such as in Jonasson et al . in which participants were informed of the diet allocation prior to assessment of baseline nutritional intake. Most studies did not sufficiently report their efforts to minimize bias and could have described how blinding of outcome assessment and the personnel involved in data handling, for instance, might contribute to minimizing bias.…”

“…For RCTs in which people with diabetes were part of a larger cohort including participants without diabetes, if separate data were not reported, authors were contacted to request the relevant values for only the participants with Type 2 diabetes. Additional or missing data were obtained from four of the five authors contacted and, where they were not available, the study was not included in the meta‐analysis. Data for the overall meta‐analyses were taken from the longest available time point for each included study.…”

Carbohydrate quantity in the dietary management of type 2 diabetes: A systematic review and meta‐analysis

“…Out of 1589 studies identified through database searches and cross reference list matching, 23 studies were included in the review (Figure ). The main reasons for exclusion were diet intervention not being low‐carbohydrate; duration of intervention being less than 3 months; study sample consisting of individuals without type 2 diabetes and studies using a non‐randomized and/ or non‐controlled trial design (Table S2).…”