Larch Arabinoglactan
Larch Arabinogalactan Unique Natural Prebiotic for Immune Support
Carolyn Perrini, CLS, CNC

Larch arabinogalactan is a well known source of dietary fiber that offers powerful therapeutic benefit as a prebiotic and as a modulator of the immune system. Of particular interest is its potential as an adjunctive supplement in the treatment of chronic diseases, including Cancer. (1)
 
Arabinogalactan (AG) is a polysaccharide found in the cell walls of a wide variety of edible and non-edible, woody plants. The wood of the western larch tree (Larix occidentalis) provides a rich harvest of free arabinogalactan from its inner bark. This complex carbohydrate helps the tree recover from injury from lightning strikes, and protects against the freeze-thaw cycles experienced in the high altitudes of the Pacific and Inland Northwest where it grows. (2)
 
Polysaccharides are often found in many medicinal herbs used for immune enhancement, including Echinacea and Astragalus. (3) AG is a fine, dry, off-white powder with a mildly sweet taste that mixes well with liquids. This safe and effective phytochemical is FDA approved for use as a dietary fiber and as a food additive. There are no known reports of toxicity. Credit for introducing larch AG into clinical practice goes to the distinguished naturopathic physician, Dr. Peter DAdamo.
 
AG Supports Digestion
 
Larch AG acts as a food supply to friendly intestinal bacteria. Like the well-known fructooligosaccharides (FOS), AG is considered a prebiotic. The non-absorbed fiber is eagerly fermented by the distal gut microflora,
resulting in an elevated production of short-chain fatty acids (SCFAs)?primarily butyrate, but also propionate. SCFAs are critically important to the health of the colon and are the principal energy source (butyrate) for the Colonic epithelial cells. (8,9) Many clinicians use prebiotics to prevent and treat intestinal conditions like diverticulosis, leaky-gut, irritable bowel syndrome (IBS) as well as inflammatory bowel diseases (IBD) like Crohn’s and ulcerative colitis.
 
Studies have shown that larch AG consumption reduces intestinal ammonia generation. (5) Reducing ammonia is significant because even low ammonia levels can have damaging effects on intestinal colonic cells. (6) AG may especially benefit patients with liver disease who are unable to detoxify ammonia, resulting in hepatic encephalopathy. (4,6,7)
 
AG Enhances Immunity
 
While larch AG is important for digestive health it has received even more attention for its ability to promote the health of the immune system. Larch AG seems to enhance immune response and may be termed a biological response modifier. (10)
 
Larch AG may be important in cancer treatment protocols due to its ability to block the metastasis of tumor cells to the liver, and to stimulate NK cell cytotoxicity. (3) Tumor metastasis to the liver is more common than to other organ sites. AG has been shown to reduce tumor cell colonization and increase survival time of subjects with various cancers. (12,13,14) Incidentally, modified citrus pectin has the same anti-metastatic mechanism of action as larch AG, but does not provide the immune-modulating effects.
 
NK cell activity is a functional marker for health. In one well-designed study, larch AG induced an increased release of interferon gamma (IFN gamma), tumor necrosis factor alpha, interleukin-1 beta (IL-1 beta) and
interleukin-6 (IL-6). This resulted in activating two powerful cells of the immune system: macrophages and NK cells. It was found that the IFN gamma was most responsible for the observed enhancement of NK cytotoxicity. (11)
 
Reports in the medical literature link decreased NK cell activity to a variety of chronic diseases including chronic fatigue syndrome, (15) viral hepatitis, (16,17) HIV/AIDS, (3) and autoimmune diseases such as multiple sclerosis. (18) The ability of larch arabinogalactans to stimulate NK activity might be the reason for the significantly improved clinical outcome of these patients.
 
Other Indications
 
Larch AG has also been shown to decrease the frequency and severity of pediatric otitis media caused by gram negative rods (especially, Escherichia coli and Klebsiella sp.) (3) (Note: Xylitol consumption also reduces the incidence of otitis media.)
 
Dosage
 
Larch arabinogalactan in powder form is typically dosed in teaspoons or tablespoons at a concentration of approximately 3 grams per teaspoon. The adult dosage is one to three teaspoons per day in divided doses. Because of its mild taste and excellent solubility in water or juice, it is easy to use with children. Clinical feedback suggests an occasional reaction of bloating and flatulence in less than three percent of individuals (mostly women). This side effect is probably due to the effect AG has on beneficially altering intestinal microflora and will often disappear after several days to one week. (10)
 
References

1. Adams MF, Ettling BV. Industrial Gums 2nd Edition; Academic Press 1973.

2. Chemstone. Theoretical Basis for Process Improvement with Chemstone OAE Technology.

3. DAdamo P. Larch arabinogalactan is a novel immune modulator. Townsend Letter for Doctors and Patients 1996, July; 156: 42-46.

4. Vince AJ, McNeil NI, Wager JD, Wrong OM. The effect of lactulose, pectin, arabinogalactan, and cellulose on the production of organic acids and metabolism of ammonia by intestinal bacteria in a faecal incubation system. Br J Nutr 1990;63:17-26.

5. Englyst HN, Hay S, Macfarlane GT. Polysaccharide breakdown by mixed populations of human faecal bacteria. FEMS Microbiol Ecology 1987;95:163-171.

6. Robinson R, Feirtag J, Slavin J. Effects of dietary arabinogalactan on gastrointestinal and blood parameters in healthy human subjects. J Amer College of Nutrition 2001; 20: 279-285.

7. Crociani F, Alessandrini A, Mucci MM, Biavati B. Degradation of complex carbohydrates by Bifidobacterium spp. Int J Food Microbiol 1994; 24:199-210.

8. Roediger WE. Utilization of nutrients by isolated epithelial cells of the rat colon. Gastroenterology 1989; 83:424-429.

9.Tsao D, Shi Z, Wong A, Kim YS. Effect of sodium butyrate on carcinoembryonic antigen production by human colonic adenocarcinoma cells in culture. Cancer Res 1983;43:1217-1222.

10. Kelly GS. Larch arabinogalactan: Clinical relevance of a novel immune-enhancing polysaccharide. Alternative Med Rev 1994; 4(2):96-103.

11. Hauer J, Anderer FA. Mechanism of stimulation of human natural killer cytotoxicity by arabinogalactan from Larix occidentalis. Cancer Immunol Immunother 1993;36:237-244.

12. Hagmar B, Ryd W, Skomedal H. Arabinogalactan blockade of experimental metastases to liver by murine hepatoma. Invasion Metastasis 1991;11:348-355.

13. Beuth J, Ko HL, Schirrmacher V,et al. Inhibition of liver tumor cell colonization in two animal tumor models by lectin blocking with D-galactose or arabinogalactan. Clin Exp Metastasis 1988;6:115-120.

14. Beuth J, Ko HL, Oette K, et al. Inhibition of liver metastasis in mice by blocking hepatocyte lectins with arabinogalactan infusions and D-galactose. J Cancer Res Clin Oncol 1987;113:51-55.

15.Levine PH, Whiteside TL,Friberg D, et al. Dysfunction of natural killer cell activity in a family with chronic fatigue syndrome. Clin Immunol Immunopathol 1998;88:96-104.

16. Machado IV, Deibis L, Risquez E, et al. Immunoclinical, molecular, and immunopathologic approach to chronic viral hepatitis. Therapeutic considerations. GEN 1994;48:124-132. [article in Spanish].

17. Corado J, Toro F, Rivera H, et al. Impairment of natural killer (NK) cytotoxicity activity in hepatitis C virus (HCV) infection. Clin Exp Immunol 1997;109:451-457.

18. Kastrukoff LF, Morgan NG, Zecchini D, et al. A role for natural killer cells in the immunopathogenesis of multiple sclerosis. J Neuroimmunol 1998;86:123-133.

Larch Arabinogalactan: Clinical Relevance of a Novel Immune-Enhancing Polysaccharide
Gregory S. Kelly, N.D.

Abstract

Larch Arabinogalactan is composed of greater than 98-percent Arabinogalactan, a highly branched polysaccharide consisting of a galactan backbone with side-chains of galactose and arabinose sugars. Larch Arabinogalactan is an excellent source of dietary fiber, and has been approved as such by the FDA. It has been shown to increase the production of short-chain fatty acids, principally butyrate and propionate, and has been shown to decrease the generation and absorption of ammonia. Evidence also indicates human consumption of Larch Arabinogalactan has a significant effect on enhancing beneficial gut microflora, specifically increasing anaerobes such as bifidobacteria and Lactobacillus . Larch Arabinogalactan has several interesting properties which appear to make it an ideal adjunctive supplement to consider in cancer protocols. Experimental studies have indicated Larch Arabinogalactan can stimulate natural killer (NK) cell cytotoxicity, enhance other functional aspects of the immune system, and inhibit the metastasis of tumor cells to the liver. The immune-enhancing properties also suggest an array of clinical uses, both in preventive medicine, due to its ability to build a more responsive immune system, and in clinical medicine, as a therapeutic agent in conditions associated with lowered immune function, decreased NK activity, or chronic viral infection.

(Altern Med Rev 1999;4(2):96-103)

Use of Larch Arabinogalactan As A Nutraceutical in Children
Prepared by Peter M. Burkholder, MD
International Clinical Research Center, Inc.
Tempe , Arizona

Larch Arabinogalactan has recently been utilized by itself or in combination with other herbs or nutraceuticals for its apparent effect on enhancement of immune responsiveness particularly in protection against microbial infections (colds, flu, and otitis). With respect to effect upon components of the immune system, Arabinogalactan have been shown to enhance natural killer lymphocyte cytotoxicity activity presumably through activation or release of selected cytokines, in particular interferon gamma. Arabinogalactans also cause increased production of other cytokines including tumor necrosis factor, interleukin-1 beta, interleukin-6, and interferon-beta and can activate phagocytic activity of the reticuloendothelial system. Certain Arabinogalactan can also activate and consume components of the complement system, particularly C3 in the absence of calcium (presumably via the alternate or properdin pathway) and C4 in the presence of calcium (presumably via the classical pathway). Apparently lower molecular weight Arabinogalactans tend to be more anti-inflammatory and anti-complementary whereas higher molecular weight Arabinogalactans tend to enhance phagocytosis and natural killer lymphocyte activities.

Dr. D'Adamo has used Arabinogalactan prophylactically to decrease the frequency and severity of otitis media in children. He believes this may be due to improved opsonization and phagocytosis of microorganisms or competitive binding of microbial fimbria. Although Dr. Peter D'Adamo, ND and an associate, Dr. Gregory S. Kelly, ND refer to these pediatric studies in review articles (Townsend Letter, #156, p42-56, 1996 and Alternative Medicine Review, vol. 4, #2, p96-103, 1999), no definitive publication on this work has yet appeared.

Dr. Linda Kim, ND of the research staff of the International Clinical Research Center, Inc has used Arabinogalactan for acute viral infections, particularly of lung, otitis media, “flu”, and colds with considerable success. She uses a dose of one teaspoon in infants under age one and 3-4 teaspoons per day for children over age one (adult doses are 3-15 gm per day). The Arabinogalactan powder is easily dissolved in water or juice making it easily palatable for children. This supplementation is done usually in acute stages of illness and for 3-4 days. A side effect, not always unwelcomed in the naturopathic and traditional Chinese Medicine models (linking of intestines with lung), is the loosening of stools in some children. This side effect presumably is due to reestablishment of selected gut microbial flora ( Lactobacillus and bifidobacteria). The above-described regimen is fairly standard practice in treatment of children with Arabinogalactan.

Gastrointestinal and Heart Health in Adults

University of Minnesota researchers reported at the Society of Experimental Biology Conference and International Food Technology Symposium their results regarding the potential health benefits derived from the consumption of larch arabinogalactan. Their abstract summary, below, reviews gastrointestinal and serum lipid (cholesterol) benefits in normal and hyperlipidemic subjects:

Arabinogalactan: Unique physiological benefits

J. SLAVIN, J. Causey, R. Robinson, R. Marett, Department of Food Science and Nutrition, University of Minnesota, 1334 Eckles Avenue, St. Paul MN 55108 USA

Arabinogalactan (AG) is a dietary fiber composed of beta-Iinked galactose and arabinose units in a 6:1 ratio. It is found in a variety of foods and herbs, such as Echinacea, and is isolated from the Western Larch and Tamarack trees for commercial use. Unlike many soluble fibers, AG is not viscous, is easily incorporated into foods and beverages, and is well accepted by consumers. We have conducted 2 clinical studies of AG (Larex, St. Paul , MN ) in healthy human subjects. In AGI, subjects consumed 15 and 30 grams of AG in a randomized feeding study. AG, consumed as non-caloric drink, increased total fecal anaerobes and decreased fecal ammonia. Both doses of AG increased monocytes. Our second study (AG2) was a parallel design where subjects consumed lower amounts of AG, 1.4, 4.4 or 8.4 g/day for 6 months. Again, AG was well tolerated and accepted by the subjects. AG at 8.4 g/day decreased serum lipids in hyperlipidemic individuals and appeared to modulate serum glucose. Additionally, AG consumption increased fecal levels of bifidobacteria and lactobacillus. Thus, AG shows promise as a novel fiber because it is a soluble dietary fiber that is easily incorporated into foods, is fermented in the gut with health-promoting physiological properties, and may have a role in immunological function.


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