Well, I had hoped to have this posted early today, but events such as network outages and poor weather conspired against me. I suppose American readers will just have to enjoy the cranberry photograph with their Thanksgiving leftovers. This image was made a few weeks ago at a cranberry field near to where I live. Every morning when home, I look out on the field, and this year finally made the time to go photograph when I saw that the field had been flooded, the fruit was floating, and harvesting was underway.
Claire writes the rest of today’s entry, which begins a series on “Plants and Medicine” as part of UBC Botanical Garden’s themes for the International Year of Biodiversity:
For my American Thanksgiving, I always remember my parents buying gelatinous cranberry jelly, and chunky cranberry jam. Much to my dismay, I was the one that had to open cans of the stuff and scoop it into bowls for the feast. It was certainly not my favourite, and I always wondered why people were so enamoured with the sticky, red and very tart substance. As it turns out, cranberries transcend more than just an old-time Thanksgiving tradition.
The photograph shows an unknown cultivated variety of Vaccinium macrocarpon (large cranberry or American cranberry), which is native to eastern Canada, eastern United States and the Territorial Collectivity of Saint Pierre and Miquelon, with a range reaching as far south as the mountains of Tennessee and North Carolina. In the heath or heather family, Four species of Vaccinium are recognized as cranberries. These are: Vaccinium macrocarpon, Vaccinium oxycoccus (common cranberry), Vaccinium microcarpum (small cranberry), and Vaccinium erythrocarpum (southern mountain cranberry). British Columbia is one of the major Canadian producers of cranberries, along with eastern Canadian provinces such as Ontario, Nova Scotia, and Quebec. In the United States, Wisconsin is the largest producer. Massachusetts and Minnesota are a few of the other major US producers. Vaccinium macrocarpon (PDF) grows on low woody vines and is cultivated in sand beds until the autumn when the fruit is ripe and red. The beds are then flooded and the berries float on the water surface where they are collected to be made into jams, sauces, juices, dried snacks and more.
The enthusiasm for Vaccinium macrocarpon and related species dates back centuries. Native peoples of North America used cranberries as food, dye and medicine long before European arrival and subsequent cultivation.
Perhaps you have heard that cranberry juice may help with urinary tract infections, ulcers, kidney stones, and a variety of other ailments. Some studies have shown that the juice of Vaccinium macrocarpon has anti-bacterial effects. One of the studied mechanisms is preventing bacteria with fimbriae (small hair-like projections) from being able to attach to cell membranes (and therefore hinder infection). A study by Yamanaka et al. published in Oral Microbiology Immunology in 2004 yielded similar results regarding the inhibition of bacterial adhesion, this time with respect to the usefulness of the juice preventing dental plaque build-up. Interesting stuff!
WebMD has a list of medical conditions for which cranberries are purported to some sort of medicinal value, ranging from antioxidant properties to memory maintenance. However, in all instances, more evidence through additional study and research is needed to verify or disprove the touted properties. Evidence to date, though, is strongest for cranberries being useful in the reduction of the ability Helicobacter pylori bacteria to live in the stomach and cause ulcers and in the prevention of urinary tract infections. So, next time you have Vaccinium macrocarpon sauce for Thanksgiving, you may want to take an extra spoonful!