Introduction:
Aloe is a cactus-type succulent plant that grows in tropical climates which is found in many skin formulas and health promoting products. Aloe gel is available for use on the skin as a gel and internally for uses such as constipation. There are several indications for which aloe vera has been noted in research to be effective but other uses which are ineffective.
Aloe and psoriasis:
Aloe used topically was found to be effective in patients with psoriasis. Patients participated in a randomized, comparative, double-blind designed trial. Patients treated with aloe vera cream (described as a 70% mucilage in the study) applied to the skin had a significantly greater reduction in the Psoriasis Area and Severity Index (PASI) after eight weeks of treatment, than patients on 0.1% triamcinolone acetonide (TA). The PASI score decreased by an average of 7.7 points in the aloe vera group and 6.6 points in the patients treated with TA. The change in disease-related quality of life scores did not differ significantly between groups. (1)
A double-blind, placebo-controlled trial assessed topical 0.5% hydrophilic aloe vera cream applied 3 times daily for 5 consecutive days per week (maximum 4 weeks active treatment) compared with placebo cream in 60 patients with mild to moderate chronic plaque-type psoriasis. Patients were followed-up for 12 months. The treatment was well tolerated by all the patients, with no adverse drug-related symptoms. By the end of the study, the Aloe vera extract cream had cured 25/30 patients (83.3%) compared to the placebo cure rate of 2/30 (6.6%). The rate of clearing of the psoriatic plaques was also significantly better with aloe vera (82.8%) than with placebo (7.7%) (2).
Aloe and healing of different types of wounds and burns:
Dat AD et al reviewed 7 randomized controlled trials including 347 subjects on the use of topical aloe vera on burns, hemorrhoidectomy, skin biopsies, surgical wounds, and chronic pressure ulcers. The review by Dat AD found that topical aloe lowered time to heal hemorrhoidectomy wounds, but did not heal burns more quickly than silver sulfadiazine, did not show a statistically significant improvement in healing of chronic pressure wounds, and actually delayed healing in surgical wounds (3).
Aloe vera and metabolic syndrome:
Devaraj S et al performed a double-blind, placebo-controlled study using inner aloe leaf gel powder. The results were promising with significant improvements in LDL, blood glucose control and hemoglobin A1C levels (4). More research is needed.
Aloe vera toxicity:
Aloe used topically and internally:
Aloe vera used topically does not have frequent significant side effects but has been reported to induce redness of the skin, allergic contact dermatitis and phototoxicity. Aloe vera taken internally may be dangerous. There have been reports of acute kidney injury, diarrhea, electrolyte abnormalities, and drug interactions. (5)
Aloe vera and liver dysfunction:
Aloe vera was found to be associated with liver damage in three women aged 57, 62, and 55 years old who had been taking aloe vera for months. After being admitted to the hospital for acute hepatitis, swelling and inflammation of the liver (lasting less than six months), aloe vera was discontinued and liver function returned to normal (6).
Aloe vera as a carcinogen:
Aloe vera leaf extract fed to rats in drinking water for 2 years resulted in significant increase in tumors of the large intestine (7).
Assessment and Plan: Aloe vera
- According to 2 trials, aloe vera cream or topical 0.5% hydrophilic aloe vera cream may be an effective treatment for improving psoriasis without the adverse effects that can be seen with steroid creams. More studies need to be done to reinforce effectiveness and standardize an ideal formula (1-2).
- The review by Dat AD et al found that topical aloe lowered time to heal hemorrhoidectomy wounds, but did not heal burns more quickly than silver sulfadiazine, did not show a statistically significant improvement in healing of chronic pressure wounds, and actually delayed healing in surgical wounds (3).
- Devaraj S et al performed a promising double-blind, placebo-controlled study using inner aloe leaf gel powder which were promising with significant improvements in LDL, blood glucose control and hemoglobin A1C levels (4). Concerns of significant toxicity when Aloe vera is taken internally limits this use until further research defines any benefit over risk of this agent.
- Aloe vera used topically is generally safe but has been reported to induce redness of the skin, allergic contact dermatitis, and phototoxicity (5). Aloe vera should not be taken internally because this may result in acute kidney injury, diarrhea, electrolyte abnormalities, and drug interactions (5). There have been reports of liver toxicity (6). Aloe vera leaf extract fed to rats in drinking water for 2 years resulted in significant increase in tumors of the large intestine (7).
References:
1.Choonhakarn C, Busaracome P, Sripanidkulchai B, Sarakarn P. A prospective, randomized clinical trial comparing topical aloe vera with 0.1% triamcinolone acetonide in mild to moderate plaque psoriasis. J Eur Acad Dermatol Venereol. 2010 Feb;24(2):168-72. http://www.ncbi.nlm.nih.gov/pubmed/19686327
2.Syed TA, Ahmad SA, Holt AH, et al. 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):505-509. http://www.ncbi.nlm.nih.gov/pubmed/8765459
3.Dat AD, Poon F, Pham KB, Doust J. Aloe vera for treating acute and chronic wounds. Cochrane Database Syst Rev. 2012 Feb 15;2:CD008762. http://www.ncbi.nlm.nih.gov/pubmed/22336851
4.Devaraj S, Yimam M, Brownell LA, Jialal I, Singh S, Jia Q. Effects of Aloe vera supplementation in subjects with prediabetes/metabolic syndrome. Metab Syndr Relat Disord. 2013 Feb;11(1). http://www.ncbi.nlm.nih.gov/pubmed/23035844
5.Boudreau MD, Beland FA. An evaluation of the biological and toxicological properties of Aloe barbadensis (miller), Aloe vera. . J Environ Sci Health C Environ Carcinog Ecotoxicol Rev. 2006 Apr;24(1):103-54. http://www.ncbi.nlm.nih.gov/pubmed/16690538
6.Yang HN, Kim DJ, Kim YM, Kim BH, Sohn KM, Choi MJ, Choi YH. Aloe-induced toxic hepatitis. Korean Med Sci. 2010 Mar;25(3):492-5. http://www.ncbi.nlm.nih.gov/pubmed/20191055
7.Boudreau MD, Mellick PW, Olson GR, Felton RP, Thorn BT, Beland FA. Clear evidence of carcinogenic activity by a whole-leaf extract of Aloe barbadensis miller (aloe vera) in F344/N rats. Toxicol Sci. 2013 Jan;131(1):26-39. http://www.ncbi.nlm.nih.gov/pubmed/22968693