- Category: Diet & Fitness
- Published: 02 February 2011
- Written by Administrator
Strawberry and Apple Compounds May Regulate Glucose Transport According To New Study
Healthful Antioxidants, Carotenoids, Phytonutrients, Phenolic Compounds Derived From Fruit and Vegetable Sources Are
Beneficial For Cardiovascular Health, Diabetes And Are The Subject of Ongoing Research
Polyphenols and phenolic acids from strawberry and apple may decrease glucose uptake by blocking transport through human intestinal cells, according to a new study.
The research, published in Molecular Nutrition & Food Research, suggests that some polyphenols, phenolic acids
and tannins extracted from apples and strawberries may block the transport of glucose across intestinal tissues,
potentially reducing glucose spikes after meals.
"Our results indicate that unsweetened beverages rich in these dietary phenolic compounds might provide a dietary
mechanism to dampen, blunt or regulate intestinal sugar absorption, a potentially important factor in the management
of diabetes and the metabolic syndrome," said researchers from the School of Food Science and Nutrition at the
University of Leeds in the U.K.
They added that their study is the first to show an inhibition of glucose transport across intestinal tissue by phenolic fruit extracts, and further characterize the contribution of individual phenolic components for their role in the inhibition of glucose
Repeated after meal (post-prandial) blood plasma glucose 'spikes' are associated with an increased risk of developing
cardiovascular diseases, metabolic syndrome and type II diabetes. Reduction of post-prandial glucose concentration
in blood is potentially beneficial.
"There is recent evidence that some bioactive compounds including polyphenols, phenolic acids and tannins (PPTs),
can affect the shape of the blood glucose curve. Some studies have shown that these compounds may result in
an altered pattern of intestinal glucose uptake, possibly due to interactions between compounds and sugar transporters," said the authors.
They said that PPTs have the potential to "readily affect glucose absorption in the small intestine," noting that many
polyphenols, phenolic acids and tannins can interact with certain sugar transporters - for example, inhibition of sodium-dependent glucose transporter 1 (SGLT1 - an active transport mechanism in which glucose is co-transported with sodium ion) or by inhibition of GLUT2.
Apples and strawberries, which are also used for producing fruit juices, are high in flavonoids and phenolic acids, the researchers noting that compounds in strawberries include anthocyanins, flavonols, flavanols and ellagic acids. Apples are known to contain flavanols, hydroxycinnamic acids, dihydrochalcones, phloridzin (phloretin glucoside),
and phloretin xyloglucoside.
"Data indicate that the polyphenols, phenolic acids and tannins from strawberry and apple are potent inhibitors of
GLUT2 and SGLT1 at concentrations predicted after dietary ingestion. Therefore, the consumption of strawberry and
apple juices could affect glucose absorption via the inhibition of glucose transport," said the researchers.
The researchers also investigated the effects of individual PPT extracts from apples and strawberries. They observed
that Quercetin-3-O-rhamnoside, phloridzin, and 5-caffeoylquinic acid contributed 26, 52 and 12 percent
of inhibitory activity of the apple extract respectively, whereas only pelargonidin-3-O-glucoside was found to
contribute to the total inhibitory activity in the strawberry extract.
"The results obtained demonstrate that polyphenols, phenolic acids and tannin-rich extracts from strawberry
and apple were able to influence glucose uptake into the cells and transport by inhibiting activities of the glucose
transporters," explained the authors.
They added that these important new findings will assist in the design of future studies.
Source: Molecular Nutrition & Food Research Volume 54, Issue 12, pages 1773-1780, "Polyphenols and phenolic acids from strawberry and apple decrease glucose uptake and transport by human intestinal Caco-2 cells"
Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment.