Aloe Vera

Overview

Almost everybody is familiar with the use of aloe for soothing sunburns, but much less known is the internal use of aloe. The active substances in aloe are thought to be the immunomodulatory gel polysaccharides (especially the acetylated mannans) and also glycoproteins. There should be a differentiation between the mucilaginous gel that is used from the parenchymatous cells that is used for a number of curative purposes, and the bitter yellow exudate that is from the bundle sheath cells, which is mainly used for its purgative properties (Grindlay and Reynolds, 1986). Among the topical uses of aloe are for skin irritations, to prevent irritation or skin injury from radiation, for mouth ulcers, for herpes, frostbite minimization, and periodontal use (Rieger and Carson, 2002; McCauley et al., 1990). Among the internal uses of aloe are for diabetes/blood sugar control, for mouth and stomach ulcers, lowering of cholesterol, for immune system support, inflammatory bowel disease and as a laxative (Borrelli and Izzo, 2000; Reynolds and Dweck, 1999).

Comments

Even though the scientific support behind aloe has not caught up to its popularity in usage, this will probably not stop people from using it, as it tends to be a favorite for topical use. The internal use of aloe will take time for people to become educated on how to use aloe correctly, and whether or not it is effective through clinical research.

Scientific Support

Blood Sugar Regulation, Diabetes, and Wound Healing

A systematic review of aloe vera published research was conducted on the clinical data to assess its clinical effectiveness. Only controlled trials were included in the review, and all indications were included. Ten studies were found, and they indicated that oral administration of aloe could be beneficial for reducing blood lipid levels in patients with hyperlipidaemia. Topical administration was found not to be an effective preventative for radiation-induced injuries. However, topical administration might be effective for genital herpes and psoriasis, but it was unclear if aloe vera promoted wound healing. The authors cautioned that the results of the trials were very preliminary, and still needed clinical work to define the parameters and effectiveness of treatments (Vogler and Ernst, 1999).

Skin irritations and Burns

A systematic review of complimentary and alternative published literature was conducted to provide a brief overview on CAM medicine use and on two conditions, atopic dermatitis and chronic venous insufficiency and two treatment modalities, aloe vera gel and tea tree oil. For neither the aloe vera gel nor the tea tree oil did the authors conclude there to be compelling evidence of effectiveness (Ernst et al., 2002).

A prospective, randomized, blinded clinical trial was conducted to ascertain whether aloe vera might be helpful to decrease the skin reactions to radiation therapy. Patients were dived into two groups and randomized and either used aloe vera plus a mild detergent, or just the mild detergent alone. A protective effect for adding aloe to the treatment regimen was only found at the high dosing levles (>2,700 cGy), and only over time (Olsen et al., 2001).

In an open, uncontrolled, clinical study to investigate the efficacy of a bioadhesive patch (aloe vera hydrogel- Aloex patch) for aphthous stomatitis (mouth ulcers), 31 patients were administered at least 3 patches daily for 4 days. The study resulted in large improvements from the treatment with the patches in symptomology and pain, and the compliance was also markedly high (Andriani et al., 2000).

Two phase III studies were conducted to ascertain if aloe vera gel could be helpful for preventing radiation therapy-induced dermatitis. The first was a randomized, double-blind, placebo-controlled (with a placebo gel) study involving 194 women that were receiving breast or chest wall irradiation. The second was a placebo-controlled randomized study involving 108 patients with the aloe vs. no treatment. Aloe vera gel was not found to protect against radiation-induced dermatitis in either of the studies (Williams et al., 1996).

Syed et al. (1996) studied the efficacy of aloe vera extract 0.5% in a hydrophilic cream for its effectiveness in treating psoriasis vulgaris. The sixty patients with slight to moderate chronic plaque-type psoriasis and PASI (Psoriasis Area and Severity Index) scores between 4.8 and 16.7 were randomized into two parallel groups to received either 100 g tube of aloe or placebo. The patients were told to self-administer the cream topically at home for 3 times daily for 5 consecutive days per week (for a maximum of 4 weeks treatment). Treatment was well tolerated, and there were no adverse effects reported. The aloe vera extract 0.5% in the hydrophilic cream was statistically more effective than the placebo in curing the psoriasis lesion and lowering the PASI score.

Visuthikosol et al. (1995) compared the effectiveness in healing burn wounds with aloe vera gel compared to vaseline gauze. Aloe vera gel healed the burn wounds statistically faster than the vaseline gauze, with a healing time of 11.89 days for the aloe treatment vs. 18.19 days for the vaseline. In the histological examination of the healing it revealed that there was earlier epithelialization in the aloe group.

Immunity and Cancer

Lissoni et al (1998) studied the immunomodulating effect of aloe vera when used along with pineal indole melatonin (MLT) in pateints with advanced solid tumors for which no effective standard anticancer techniques are available. The 50 participants were given either MLT alone (20 mg/day orally in the dark period) or MLT plus aloe vera tincture (1 ml two times daily). The percent 1-year survival rate was higher in the aloe treatment group versus the MLT alone group, and stable disease was achieved in this group in a higher portion of the people. The authors concluded that MLT plus aloe vera extracts may produce therapeutic benefits, including stabilization of disease and survival, in patients with advanced solid tumors.

Safety / Dosage

The dosage of aloe depends on the preparation and the usage, of which there are many. Generally, as a laxative, aloe is used in the range of 50-200 mg daily or about 1-3 ounces orally. For topical applications the gel is generally applied throughout the day as needed.

No significant side effects of aloe vera gel have been noted, except the occasional allergy. One study found anthranoid laxative abuse (such as aloe vera gel) to be linked to colorectal cancer (Siegers et al., 1993).

References

1.Andriani E, Bugli T, Aalders M, Castelli S, De Luigi G, Lazzari N, Rolli GP. The effectiveness and acceptance of a medical device for the treatment of aphthous stomatitis. Clinical observation in pediatric age. Minerva Pediatr. 2000 Jan-Feb;52(1-2):15-20.

2.Borrelli F, Izzo AA. The plant kingdom as a source of anti-ulcer remedies. Phytother Res. 2000 Dec;14(8):581-91.

3.Ernst E, Pittler MH, Stevinson C. Complementary/alternative medicine in dermatology: evidence-assessed efficacy of two diseases and two treatments. Am J Clin Dermatol. 2002;3(5):341-8.

4.Grindlay D, Reynolds T. The Aloe vera phenomenon: a review of the properties and modern uses of the leaf parenchyma gel. J Ethnopharmacol. 1986 Jun;16(2-3):117-51.

5.Lissoni P, Giani L, Zerbini S, Trabattoni P, Rovelli F. Biotherapy with the pineal immunomodulating hormone melatonin versus melatonin plus aloe vera in untreatable advanced solid neoplasms. Nat Immun. 1998;16(1):27-33.

6.McCauley RL, Heggers JP, Robson MC. Frostbite. Methods to minimize tissue loss. Postgrad Med. 1990 Dec;88(8):67-8, 73-7.

7.Olsen DL, Raub W Jr, Bradley C, Johnson M, Macias JL, Love V, Markoe A. The effect of aloe vera gel/mild soap versus mild soap alone in preventing skin reactions in patients undergoing radiation therapy. Oncol Nurs Forum. 2001 Apr;28(3):543-7.

8.Reynolds T, Dweck AC. Aloe vera leaf gel: a review update. J Ethnopharmacol. 1999 Dec 15;68(1-3):3-37.

9.Rieger L, Carson RE. The clinical effects of saline and aloe vera rinses on periodontal surgical sites. J Okla Dent Assoc. 2002 Winter;92(3):40-3.

10.Robinson M. Medical therapy of inflammatory bowel disease for the 21st century. Eur J Surg Suppl. 1998;(582):90-8.

11.Siegers CP, von Hertzberg-Lottin E, Otte M, Schneider B. Anthranoid laxative abuse--a risk for colorectal cancer? Gut. 1993 Aug;34(8):1099-101.

12.Syed TA, Ahmad SA, Holt AH, Ahmad SA, Ahmad SH, Afzal M. Management of psoriasis with Aloe vera extract in a hydrophilic cream: a placebo-controlled, double-blind study. Trop Med Int Health. 1996 Aug;1(4):505-9.

13.Vogler BK, Ernst E. Aloe vera: a systematic review of its clinical effectiveness. Br J Gen Pract. 1999 Oct;49(447):823-8.

14.Williams MS, Burk M, Loprinzi CL, Hill M, Schomberg PJ, Nearhood K, O'Fallon JR, Laurie JA, Shanahan TG, Moore RL, Urias RE, Kuske RR, Engel RE, Eggleston WD. Phase III double-blind evaluation of an aloe vera gel as a prophylactic agent for radiation-induced skin toxicity. Int J Radiat Oncol Biol Phys. 1996 Sep 1;36(2):345-9.

15.Visuthikosol V, Chowchuen B, Sukwanarat Y, Sriurairatana S, Boonpucknavig V. Effect of aloe vera gel to healing of burn wound a clinical and histologic study. J Med Assoc Thai. 1995 Aug;78(8):403-9.

EDITOR'S NOTE: This monograph can be found in The Health Professional's Guide to Dietary Supplements (Lippincott, Williams & Wilkins) by Shawn M. Talbott, PhD and Kerry Hughes, MS.

Prebiotics

Overview

Fructo-oligosaccharides (FOS) also called “prebiotics” are a group of non-digestible compounds that stimulate the growth of beneficial microflora (note: this is different than PRO-biotics, or the actual beneficial bacteria such as acidophilus and bifidum). In terms of chemistry, a fructo-oligosaccharide (FOS) is a glucose molecule bonded to multiple fructose molecules. These bonds cannot be broken down by enzymes in the human small intestine - allowing the FOS to reach the large intestine intact, where it becomes a substrate for colonic bacteria. The effects of short-chain FOS have been studied for nearly two decades. Groups of oligosaccharides can be found in foods such as beans, blueberries, and onions; a liquid supplement is available in Japan, and FOS is available in capsule form in the U.S.

Comments

Prebiotics have been shown to selectively stimulate the growth and activity of benefical bacteria in the colon. The prebiotic, fructooligosaccharide (FOS), is found naturally in many foods, such as wheat, onions, bananas, honey, garlic, and leeks – and FOS can also be isolated from chicory root or synthesized enzymatically from sucrose (both more commonly found in FOS dietary supplements). Fermentation of FOS in the colon results in a large number of physiologic effects including increasing the numbers of bifidobacteria in the colon, increasing calcium absorption, increasing fecal weight, shortening of gastrointestinal transit time, and possibly lowering blood lipid levels.

Based on the available scientific evidence, FOS supplements are generally claimed to boost levels and activity of beneficial gut bacteria and thus promote general gut health, reduce serum lipids, increase intestinal calcium absorption, alleviate antibiotic-induced diarrhea, and reduce both the severity of irritable bowel syndromes and the risk of colon cancer.

Scientific Support

Short-chain FOS is metabolized in the colon (by colonic bacteria) into short-chain fatty acids (Giacco et al. 2004). These short-chain fatty acids cause a drop in pH, which may inhibit the growth of pathogenic bacteria, facilitate intestinal calcium absorption, and act as an energy substrate for colonic epithelial cells (Bouhnik et al. 1999, Tahiri et al. 2001). By manipulating colonic pH and microflora content, FOS may also play a protective role against colon cancer (Giacco et al. 2004, Swanson et al. 2002, Ten Bruggencate et al. 2003 and 2004). Research also points to a reduction in liver fatty acid synthesis as a possible mechanism for serum lipid reduction (Giacco et al. 2004, Swanson et al. 2002).

Human studies have shown significant increases in bifidobacteria (beneficial bacteria in the gut) from ingestion of as little as 6-8 grams of short-chain FOS per day (Chow 2002). Research has also shown decreases in pathogenic colonic bacteria from FOS ingestion (Chow 2002). There is evidence that short-chain FOS can lower cholesterol and triglycerides, but most of this research has involved animal models. Colon tumors and indicators of cancer have also been reduced in animal models. Although animal studies have given promising results, relatively few human studies have shown that mineral absorption can be enhanced from FOS ingestion (Tahiri et al. 2001).

Safety/Dosage

Since the bonds of FOS are not digestible, bacterial metabolism in the large intestine produces gas and bloating. Flatulence is a common symptom associated with FOS ingestion and can be worse in people who are lactose intolerant (depending on how the FOS is processed). Studies have shown that the severity of symptoms is dose-dependent (less FOS = less symptoms). Ingestion of 20-30 grams per day has been associated with the onset of severe discomfort – but symptoms may be alleviated by starting with a small dose and increasing gradually to the desired amount (Bouhnik et al. 1999). Ten grams of FOS per day appears to be the “optimal” dose, since this amount produces a significant increase in bifidobacteria and is fairly well-tolerated.

References

1.Alles MS, Hautvast JG, Nagengast FM, Hartemink R, Van Laere KM, Jansen JB. Fate of fructo-oligosaccharides in the human intestine. Br J Nutr. 1996 Aug;76(2):211-21.

2.Bouhnik Y, Flourie B, Riottot M, Bisetti N, Gailing MF, Guibert A, Bornet F, Rambaud JC. Effects of fructo-oligosaccharides ingestion on fecal bifidobacteria and selected metabolic indexes of colon carcinogenesis in healthy humans. Nutr Cancer. 1996;26(1):21-9.

3.Bouhnik Y, Vahedi K, Achour L, Attar A, Salfati J, Pochart P, Marteau P, Flourie B, Bornet F, Rambaud JC. Short-chain fructo-oligosaccharide administration dose-dependently increases fecal bifidobacteria in healthy humans. J Nutr. 1999 Jan;129(1):113-6.

4.Chow J. Probiotics and prebiotics: A brief overview. J Ren Nutr. 2002 Apr;12(2):76-86.

5.Djouzi Z, Andrieux C. Compared effects of three oligosaccharides on metabolism of intestinal microflora in rats inoculated with a human faecal flora. Br J Nutr. 1997 Aug;78(2):313-24.

6.Flickinger EA, Hatch TF, Wofford RC, Grieshop CM, Murray SM, Fahey GC Jr. In vitro fermentation properties of selected fructooligosaccharide-containing vegetables and in vivo colonic microbial populations are affected by the diets of healthy human infants. J Nutr. 2002 Aug;132(8):2188-94.

7.Giacco R, Clemente G, Luongo D, Lasorella G, Fiume I, Brouns F, Bornet F, Patti L, Cipriano P, Rivellese AA, Riccardi G. Effects of short-chain fructo-oligosaccharides on glucose and lipid metabolism in mild hypercholesterolaemic individuals. Clin Nutr. 2004 Jun;23(3):331-40.

8.Gibson GR. Dietary modulation of the human gut microflora using prebiotics. Br J Nutr. 1998 Oct;80(4):S209-12.

9.Luo J, Van Yperselle M, Rizkalla SW, Rossi F, Bornet FR, Slama G. Chronic consumption of short-chain fructooligosaccharides does not affect basal hepatic glucose production or insulin resistance in type 2 diabetics. J Nutr. 2000 Jun;130(6):1572-7.

10.Moore N, Chao C, Yang LP, Storm H, Oliva-Hemker M, Saavedra JM. Effects of fructo-oligosaccharide-supplemented infant cereal: a double-blind, randomized trial. Br J Nutr. 2003 Sep;90(3):581-7.

11.Piche T, des Varannes SB, Sacher-Huvelin S, Holst JJ, Cuber JC, Galmiche JP. Colonic fermentation influences lower esophageal sphincter function in gastroesophageal reflux disease. Gastroenterology. 2003 Apr;124(4):894-902.

12.Rao AV. Dose-response effects of inulin and oligofructose on intestinal bifidogenesis effects. J Nutr. 1999 Jul;129(7 Suppl):1442S-5S.

13.Roberfroid M. Dietary fiber, inulin, and oligofructose: a review comparing their physiological effects. Crit Rev Food Sci Nutr. 1993;33(2):103-48.

14.Roberfroid MB, Van Loo JA, Gibson GR. The bifidogenic nature of chicory inulin and its hydrolysis products. J Nutr. 1998 Jan;128(1):11-9.

15.Roberfroid MB. Prebiotics and synbiotics: concepts and nutritional properties. Br J Nutr. 1998 Oct;80(4):S197-202.

16.Schaafsma G, Meuling WJ, van Dokkum W, Bouley C. Effects of a milk product, fermented by Lactobacillus acidophilus and with fructo-oligosaccharides added, on blood lipids in male volunteers. Eur J Clin Nutr. 1998 Jun;52(6):436-40.

17.Swanson KS, Grieshop CM, Flickinger EA, Bauer LL, Wolf BW, Chow J, Garleb KA, Williams JA, Fahey GC Jr. Fructooligosaccharides and Lactobacillus acidophilus modify bowel function and protein catabolites excreted by healthy humans. J Nutr. 2002 Oct;132(10):3042-50.

18.Tahiri M, Tressol JC, Arnaud J, Bornet F, Bouteloup-Demange C, Feillet-Coudray C, Ducros V, Pepin D, Brouns F, Rayssiguier AM, Coudray C. Five-week intake of short-chain fructo-oligosaccharides increases intestinal absorption and status of magnesium in postmenopausal women. J Bone Miner Res. 2001 Nov;16(11):2152-60.

19.Ten Bruggencate SJ, Bovee-Oudenhoven IM, Lettink-Wissink ML, Katan MB, Van Der Meer R. Dietary fructo-oligosaccharides and inulin decrease resistance of rats to salmonella: protective role of calcium. Gut. 2004 Apr;53(4):530-5.

20.Ten Bruggencate SJ, Bovee-Oudenhoven IM, Lettink-Wissink ML, Van der Meer R. Dietary fructo-oligosaccharides dose-dependently increase translocation of salmonella in rats. J Nutr. 2003 Jul;133(7):2313-8.

21.van Dokkum W, Wezendonk B, Srikumar TS, van den Heuvel EG. Effect of nondigestible oligosaccharides on large-bowel functions, blood lipid concentrations and glucose absorption in young healthy male subjects. Eur J Clin Nutr. 1999 Jan;53(1):1-7.

EDITOR'S NOTE: This monograph can be found in The Health Professional's Guide to Dietary Supplements (Lippincott, Williams & Wilkins) by Shawn M. Talbott, PhD and Kerry Hughes, MS.