Research from Finland's University of Turku has confirmed that a compound found in the bark of the Spruce tree and apparently other tree wood barks is a powerful and functional prebiotic that feeds our healthy gut bacteria.
The researchers determined that the compound, galactoglucomannan, is the primary component of the hemicellulose present in many softwood tree species. The researchers extracted galactoglucomannan from the Spruce tree (Picea abies), and then fed it to probiotic bacteria in the laboratory.
The newfound prebiotic was fed to three human probiotic species - Bifidobacterium animalis subsp. lactis Bb12 (B. lactis Bb12), Bifidobacterium longum and Lactobacillus rhamnosus GG. The testing confirmed that all three species of bacteria consumed and thrived from the wood-sourced prebiotic.
By definition, prebiotics are non-digestible by the host. This means that we do not digest these prebiotics, with include fructooligosaccharides (FOS), galactooligosaccharides (GOS), inulin and other oligosaccharides like galactoglucomannan. Good food sources of prebiotics include onions, apples, oats, barley, chicory root, onions, bananas, asparagus, dairy products, fibrous vegetables and many others.
The researchers also determined that galactoglucomannan's ability to promote the growth of intestinal probiotics was comparable to levels found in fructooligosaccharide.
This point also supports the notion, as many have thought, that the barks of many tree species have been consumed by our ancestors as a food source. This only adds to the understanding that humans have traditionally consumed not just the fruits of many trees, but also their roots, bark and leaves for medicinal purposes as well as nutritional purposes.
This also supports the fact that spruce bark has been used traditionally to aid in digestive issues. Because the bark feeds and stimulates the growth of our intestinal bacteria as well as supplies polyphenols and other anti-inflammatory phytonutrients, spruce bark is now a confirmed medicinal food.
Native Americans and other traditional cultures have chewed the inner bark of the spruce along with the shoots to treat urinary tract infections, influenza, colds, rheumatism and even tuberculosis. The bark has also been placed on wounds to promote healing and preventing infection.
Spruce tree shoots are also rich in vitamin C. Captain Cook and his crew reportedly used spruce beer (was alcoholic and non-alcoholic) to help prevent scurvy. The food industry now uses spruce oil for chewing gum and as a flavoring agent.
Spruce bark's ability to stimulate digestive health was also confirmed in a recent study of a galactoglucomannan complex called GGMO-AX. The feeding was found to suppress the virulence of Salmonella typhimurium within the birds.
The researchers discussed the newfound availability of these important prebiotics. "Hemicellulose is an untapped natural resource, which can be produced economically in large quantities, therefore, the study of probiotics and hemicellulose together could also have potential for symbiotic formulations," they commented.
- Polari L, Ojansivu P, Mäkelä S, Eckerman C, Holmbom B, Salminen S. Galactoglucomannan Extracted from Spruce (Picea abies) as a Carbohydrate Source for Probiotic Bacteria. J Agric Food Chem. 2012 Nov 7;60(44):11037-43. doi:10.1021/jf303741h. Epub 2012 Oct 24.
- Faber TA, Dilger RN, Iakiviak M, Hopkins AC, Price NP, Fahey GC Jr. Ingestion of a novel galactoglucomannan oligosaccharide-arabinoxylan (GGMO-AX) complex affected growth performance and fermentative and immunological characteristics of broiler chicks challenged with Salmonella typhimurium. Poult Sci. 2012 Sep;91(9):2241-54.