The Effects of L-Arabinose on Intestinal Sucrase Activity in Man

The purpose of this study is to investigate the effect of L-arabinose in a sugar-rich meal on intestinal sucrase activity in healthy volunteers by measuring postprandial blood glucose and insulin, and selected intestinal hormonal responses to increasing doses of L-arabinose.

Background:

The intake of common table sugar (sucrose) in the industrialised countries is relatively high. In Denmark the daily intake of sugar is in the range of 30-40 g/d exclusive the intake of sugar containing drinks. The health consequences of this relatively high sugar intake are heavily debated in the media. One of the arguments is that a high sugar intake may be one of the factors involved in the development of the metabolic syndrome, including overweight, increased blood glucose and insulin levels as well as impaired insulin action.

L-arabinose is widely distributed in plants and is a common component in plant cell walls in maize, wheat, rye, rice, plant gums etc. The isolated 5-carbon sugar has been shown to suppress the increase of blood glucose and plasma insulin after ingestion of sucrose in rats by inhibition of sucrase activity. In vitro studies on Caco-2 cells indicate that L-arabinose is a potent inhibitor on sucrase activity, possibly in a non-competitive way.

Potential nutritional advantages of consuming L-arabinose in combination with sucrose may therefore be a delayed digestion of sucrose and a lower absorption of glucose, resulting in both lower blood glucose and insulin levels. A delayed digestion of sucrose will reduce the energy utilisation with the potential of reducing weight gain in human subjects.

Methods:

This dose-response study with 14 healthy male volunteers has a randomised cross-over design based on four single "meals" separated by one week wash-out periods. Sugar rich drinks supplemented with different doses of L-arabinose will be tested with respect to postprandial blood glucose, insulin, triglyceride, GIP and GLP-1. Postprandial blood samples will be taken every 15 to 30 min for 180 min. Appetite sensations will be measured every 30 min during the experiment. After 180 minutes an ad libitum lunch will be served and EI will be registered.

Inclusion Criteria:

• healthy males
• BMI between 18.4-25 kg/m2
• age between 18 and 30

Exclusion Criteria:

• donation of blood 3 months before or during the study
• gastrointestinal disorders, diabetes, hypertension, hyperlipidemia, chronic infectious disease (HIV or hepatitis)
• smoking
• consumption of more than 21 alcoholic drinks/week
• elite athletes
• on medication