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NutrInsight • Slow-release carbohydrates: Growing evidence on metabolic responses and public health interest

3 MNGINELETYWCECHRLEYAEMSNEITMCISOREMFERSSRGPEOINODFGNUASCECIEVTNTIIGDOOETNHHNOEECLFEPPPOPOSRLTEYPVPREHANENTNDOIALLS:

METABOLIC DISEASES

Prof. Edith Feskens, Chair in Nutrition and Health over the Lifecourse, Wageningen
University, Netherlands

Diabetes and metabolic syndrome (MetS) are a significant and growing concern worldwide. Increasing evidence
supports the importance of controlling post-meal glucose levels to help prevent metabolic diseases. After
having reminded the public health concerns and the mechanisms involved in the genesis of hyperglycemia,
Prof. Edith Feskens presented interesting results from oral glucose tolerance tests that highlight the role of
postprandial hyperglycemia in the genesis of metabolic diseases and the interest of controlling glycemia by
lifestyle interventions. She also described mechanisms involving postprandial hyperglycemia in cardiovascular
disease development.

3.1 The public health issues

The prevalence of metabolic syndrome is increasing worldwide

Metabolic syndrome (MetS) is defined as having central obesity and two of the following criteria: a high blood
triglyceride level (≥150 mg/dl), high blood pressure (systolic blood pressure ≥130 mm Hg or diastolic blood
pressure ≥85 mm Hg), a low level of HDL cholesterol (HDL cholesterol <40 mg/dl in men and <50 mg/dl in
women), and an elevated fasting glucose level (≥100 mg/dl) [IDF, 2006].

As the MetS criteria include a large panel of metabolic disorders, different phenotypes can be classified into
clusters that are related to different metabolic risk factors. For the abdominal adiposity–dominant phenotype,
the primary focus will be on the risk of sleep-disordered breathing and fatty liver disease. For the vascular
dominant phenotype, the main concern will be on hypertension and stroke or coronary heart disease. The
insulin-resistant dominant phenotype is linked more to type 2 diabetes or gestational diabetes. For subjects
with high lipid dominant phenotype, the risk of atherogenic dyslipidemia is addressed first.

The prevalence of MetS is estimated at around 25% of world’s adult population, with a potentially higher
prevalence in the United States (around 30%). The underlying causes of MetS are still a matter of discussion,
but both insulin resistance and central obesity are considered significant factors.

The postprandial stage represents a large part of the day

For most of the day, individuals are not in the fasting state, but are fed, and hence in some sort of postprandial
stage (see Figure 12). With the recent introduction of reliable and comfortable continuous glucose monitoring
systems, it has become possible to precisely investigate daily fluctuations in glucose levels. Daily glycemic
variations are related to what the subjects eat and what they do. Use of these monitoring systems has already
revealed interesting fluctuations between different groups, and their further use in intervention studies will
provide important results to help better understand the link between the postprandial glycemic response and
metabolic risk factors.

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