is commonly used both topically and internally for a whole catalogue of conditions. However, is there any evidence that it works?
One of the most popular uses of aloe vera is for healing burns, and there's considerable evidence to back up its effectiveness for such wounds. When an aloe-based cream was pitted against the antimicrobial cream silver sulphadiazine in 30 patients with second-degree burns, the burns treated with aloe healed significantly faster than those treated with the standard over-the-counter treatment (Surg Today, 2009; 39: 587-91).
Confirming these results, a 2007 review-which pooled the data from four different studies-revealed that the burns patients treated with aloe vera healed an average of nine days sooner than those in the control groups (Burns, 2007; 33: 713-8). Neverthe-less, and interestingly, aloe vera cream has no proven efficacy for treating sunburn, for which it is so often used (J Med Assoc Thai, 2005; 88 Suppl 4: S173-6).
However, several studies suggest that aloe vera is effective for certain skin conditions, including psoriasis, seborrheic dermatitis (dandruff) and genital herpes (Indian J Dermatol, 2008; 53: 163-6). Yet, despite its well-known anti-inflammatory properties, it's not been successful in preventing or minimizing radiation-induced skin reactions, such as those seen in cancer patients (Clin Oncol [R Coll Radiol], 2005; 17: 478-84).
Where it has been showing a lot of promise lately is in treating oral-health problems. In the laboratory, an aloe vera tooth gel was found to be more effective at fighting bacteria than two popular commercial toothpastes (Gen Dent, 2009; 57: 238-41), while trials in people have reported the successful treatment of plaque, gum disease and oral lichen planus (an often painful inflammatory condition affecting the tongue and soft tissues of the mouth) with aloe vera (J Appl Oral Sci, 2008; 16: 293-6; Br J Dermatol, 2008; 158: 573-7).
There's less evidence to support the use of aloe vera taken internally, but what studies there are show promise. Oral aloe vera gel (100 mL taken twice daily for four weeks) led to significant improvement in patients with ulcera-tive colitis-a form of inflammatory bowel disease (IBD)-compared with a placebo (Aliment Pharmacol Ther, 2004; 19: 739-47).
However, a study by St George's Hospital Medical School in London found equivocal results with aloe in patients with irritable bowel syndrome (IBS), despite a trend towards symptomatic improvement (Int J Clin Pract, 2006; 60: 1080-6).
Four separate reviews of the scientific literature suggest that oral aloe vera may be useful for reducing blood glucose in diabetic patients and for lowering LDL (bad) cholesterol (Br J Gen Pract, 1999; 49: 823-8).
The herbal remedy may even be able to help in the treatment of cancer. When Italian researchers evaluated the use of oral aloe vera (A. arborescens
in this case; 10 mL three times a day) in 240 metastatic cancer patients receiving chemotherapy, those taking the aloe fared significantly better in terms of tumour regression and survival time compared with those treated with chemo alone (In Vivo, 2009; 23: 171-5).
Aloe vera products
Aloe vera contains a wealth of biologically active substances, so it's no wonder that it's proving to be so useful across such a wide range of conditions. Polysaccharides-the long-chain sugar molecules found in aloe vera gel-may, for instance, be responsible for its anti-inflammatory, antifungal and wound-healing effects (Molecules, 2008; 13: 1599-616).
However, when it comes to the aloe products available on the market, do they all provide the same benefits? According to one report, commercial, stabilized gel products may not work as well as the fresh gel, although cold processing is believed to best retain its beneficial properties (Toxicol Appl Phar-macol, 2008; 227: 125-35).
It may also be a good idea to look for products that have been certified by the International Aloe Science Council (IASC), which was set up to test the purity of the aloe contained in these products (see its website at www.iasc.org for more information).
WDDTY VOL 20 NO 11