Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. Lancet, 393(10170), 434-445. and the Otago Southland Diabetes Research Trust. 94 the light of current evidence, dietary glycaemic index or glycaemic load may be less useful as overall measures 95 of carbohydrate quality than dietary fibre and wholegrain content.

Wholegrain foods vary in the extent of processing. We investigated whether wholegrain particle size in bread influences postprandial glycemia in type 2 diabetes. RESEARCH DESIGN AND METHODS Postprandial glycemia (incremental area under the blood glucose curve [iAUC]) was measured after consumption of three breads made with roller-milled wholegrain flour and added grains and a fourth made with stone-ground flour. All flours and grains were 100% wholegrain wheat. Breads were nutrient matched. RESULTS Fifteen adults (64 6 10 years, HbA 1c 58 6 13 mmol/mol) completed the study. iAUC for the three breads made with roller-milled flour ranged from 376 to 641 mmol 21 min 21 , inverse linear trend for grain particle size P 5 0.039. The iAUC for stone-ground wholegrain bread (503) was smaller than predicted from mean particle size. CONCLUSIONS Wholegrain structural integrity in bread is a determinant of glycemic response. These findings have implications for dietary advice and the definition of the term "'wholegrain." Diets high in whole grains are associated with reduced incidence and mortality from several noncommunicable diseases (1) and are recommended in the management of type 2 diabetes (2). Although wholegrain bread has been a staple food in many cultures for thousands of years (3), wholegrain bread currently available in the food supply is frequently made from finely milled reconstituted components of whole grains (4). The structural integrity of food has been shown to influence cardiometabolic risk factors in people with type 2 diabetes (5). We have considered the extent to which the structural integrity of whole grains in bread, measured by particle size, influences postprandial glycemia in adults with type 2 diabetes. RESEARCH DESIGN AND METHODS This single-center, randomized, crossover study was prospectively registered (ACTRN12617000328370, anzctr.org.au

Aims/hypotheses We examined the effects of milling and cooking whole grains in water to achieve starch gelatinisation on postprandial blood glucose using a randomised crossover open-label design. Participants were adults with type 2 diabetes whose body weight or medications had not changed in at least 3 months. Methods Postprandial blood glucose (measured as incremental AUC [iAUC]) was measured following consumption of four nutrient-matched whole-wheat porridge test-meals. Test-meals included gelatinised or native starch and were made with either finely milled or intact whole-wheat. Results Eighteen adults (63.1 ± 9.8 years, HbA 1c 57.0 ± 11.5 mmol/mol [7.4 ± 3.2%]) completed the study. iAUC was higher following cooked meals (gelatinised starch) than following uncooked meals (native starch) (mean difference [MD] 268, 95% CI 188, 348 mmol/l × min). Consuming finely milled whole-wheat produced a higher iAUC compared with intact whole-wheat (MD 173, 95% CI 80, 266 mmol/l × min). There was no evidence of an interaction effect (p = 0.841). Conclusions Both the nature of starch and the grain structure of whole-wheat influence the glycaemic response of adults with type 2 diabetes mellitus.