Carbohydrates and Health

increases in vegetable, fruit, and grain consumption, with the increase in whole
grains intake being small (daily whole grains servings increased from 1.1 to 1.4).
Whole grains and energy intake
• Effect
• Limited evidence
• The direction of the effect demonstrates higher whole grains consumption may be
beneficial to health, but it is not possible to exclude confounding by other dietary
variables
• The effect is biologically relevant
Type 2 diabetes mellitus
8.143 Eight cohort studies in seven publications were identified that presented evidence
on whole grains intake and incidence of type 2 diabetes mellitus, all of which
were included in a meta-analysis (Meyer et al., 2000; Liu et al., 2000c; Fung et al.,
2002; Montonen et al., 2003; van Dam et al., 2006; de Munter et al., 2007; Fisher
et al., 2009). De Munter et al. 2007 reported on the Nurse’s Health Study and on
the Nurse’s Health Study 2. Two publications reported on the same study (Liu et
al., 2000c; de Munter et al., 2007) and the data from the most recent were used
in a meta-analysis (de Munter et al., 2007). One publication reporting a longer
follow-up period for three cohorts already included, was identified in the update
search (Sun et al., 2010) (Cardio-metabolic review, diabetes and glycaemia chapter;
Update search). A further meta-analysis was performed (Aune et al., 2013) which
included the studies found in the update search and also included three later
studies (Ericson et al., 2013; Parker et al., 2013; Wirstrom et al., 2013). The results from
the later meta-analysis are presented below and were used to inform this report.
8.144 An association is indicated, between higher whole grains consumption and
reduced incidence of type 2 diabetes, as indicated from the forest plot, but the
heterogeneity is above the pre-specified cut-off of 75% (I 2 =82%) and, therefore,
the pooled estimate is not reported.
Whole grains (serving/day) and type 2 diabetes mellitus
• Association
• Moderate evidence
• The direction of the association indicates higher whole grains consumption is
beneficial to health
• It is not possible to quantify the magnitude of the association due to differences
in definition and serving size used. It is therefore not possible to determine the
biological relevance of this finding
Fasting blood glucose
8.145 Four randomised controlled trials were identified that presented evidence on
whole grains intake in relation to fasting blood glucose, all of which were included
in a meta-analysis (Saltzman et al., 2001; Howard et al., 2006b; Andersson et al.,
2007; Kim et al., 2008; Tinker et al., 2008). Two publications reported on the same
trial (Howard et al., 2006b; Tinker et al., 2008); the results from Howard et al.
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