Wild Blueberries (Vaccinum angustifolium Aiton)
Fights Inflammation and Enhances Insulin Sensitivity
Jul 27, 2009
Wild blueberries, or "low bush blueberries" are deciduous low-growing shrubs (6 inches to 2 feet) indigenous to northeastern North America. In Canada, they grow uncultivated in the dry acidic soils of Newfoundland and Labrador, Prince Edward Island, Nova Scotia, New Brunswick, Ontario and Manitoba. Agriculture Canada favors the "Cumberland" and "Fundy" varieties for their high quality large fruits and sweet flavors. In the United States, V. angustifolium thrive from Connecticut to West Virginia. Blueberries bear white "bell-shaped" flowers that turn to dark blue, sweet edible berries in late summer or early autumn.
Because they are nutrient and phytochemical - rich, interest in the berries continues to increase due to their potential in preventing/treating chronic human diseases. In 2006, Dr. Sweeney-Nixon, Associate Professor of Biology at the University of PEI (Charlottetown) and her colleagues conducted a pilot study on the efficacy of blueberries on insulin sensitivity and inflammation in humans. They recruited 14 middle-aged, overweight men with a moderate risk of heart disease. The subjects were divided into 2 groups: one group received a daily ration of 250 ml (8 ounces) blueberry juice for 3 weeks, while the control group - received a placebo at the same time. After a wash-out period, the treatments were reversed. Results: Blueberry juice improved insulin sensitivity and tolerance against inflammation in the participants.
Their report was presented at the Annual Dietitians of Canada Conference June 4-6 2009, in Charlottetown, PEI.
Earlier Studies
In a similar trial by Martineau and colleagues, the researchers used extracts from the roots, stem, fruits,and leaves of Vaccinum angustifolium on incubated human cells. The extracts (12.5 micromole per ml in strength) were added to fat, muscle, and pancreatic beta cells.
Results:
- The extracts significantly enhanced glucose transport in cells by 15-25% in the presence of or the absence of insulin after 20 hours of incubation.
- In 3T3 cells, only the root and stem extracts enhanced glucose uptake, and this effect was greater after one hour than after 20 hours.
- Glucose-stimulated insulin secretion (GSIS) was made possible by a small amount of BTC-tet cells incubated overnight with leaf or stem extract.
- Stem, leaf and fruit extracts reduced apoptosis (cell suicide) of PC 12 cells by 20-30% due to glucose poisoning after exposure for 90 hours.
These outcomes shows that low-bush blueberries (V. angustifolium Ait) contains active substances with insulin-like properties and protects against the toxic effects of glucose. V. angustifolium contains 11 antidiabetic and 18 anti-inflammatory compounds.
Nutritional Content of Blueberries Per Cup (Fresh)
- Calories: 81
- Protein: 1 gram
- Carbohydrate: 20 grams
- Dietary Fiber: 4 grams
- Fat: 1 gram
- Vitamin A: 14 Retinol Equivalents (REs)
- Vitamin B1/Thiamin: .07 milligrams
- Vitamin B2/Riboflavin: .07 milligrams
- Vitamin B3/Niacin: .52 milligrams
- Vitamin B6: .05 milligrams
- Folacin: 9 milligrams
- Vitamin C: 19 milligrams
- Calcium: 9 milligrams
- Iron: .25 milligrams
- Magnesium: 7 milligrams
- Potassium: 129 milligrams
- Sodium: 9 milligrams
- Zinc:.16 milligrams
References
Voung T et al. "Fermented Canadian low-bush blueberry juice stimulates glucose uptake and AMP-activated protein kinase in insulin-sensitive cultured muscle cells and adipocytes." Canadian J of Physiology and Pharmacology 2007;85(9):956-965
Martineau LC et al. " Anti-diabetic properties of Canadian lowbush blueberry (Vaccinum angustifolium Ait.)" Phytomedicine November 2006;13(9-10):612-623
Whitney EN & Rolfes SR "Understanding Nutrition" Ninth Edition Wadsworth 2002 p.H-12
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