Oral Aloe Vera for Treatment of Diabetes Mellitus and Dyslipidemia

Clinical Trials

Electronic searches for articles containing the keyword "aloe" were performed in the following databases: MedLine, the Cumulative Index to Nursing and Allied Health Literature, the Cochrane Library, Excerpta Medica Database, HerbMed, and International Pharmaceutical Abstracts. Manual searches were conducted of relevant references. All articles examining oral use of aloe vera and measuring either blood or serum glucose, HbA_1c, or any lipid parameter were extracted for review and analysis. Nonhuman studies and those using an aloe species other than A. barbadensis were excluded. One study was available only in Spanish and was translated to English by an independent Spanish-speaking clinician. A meta-analysis of the extracted studies was not possible because of inadequate reporting of data.

Eight trials were found, including a total of 5285 patients, that assessed oral aloe vera use in humans.^[21–28] Seven of the studies evaluated diabetes endpoints and six evaluated effects on lipids. Five of these studies evaluated endpoints for both conditions. Of the eight studies investigating aloe vera treatment for diabetes mellitus or lipid endpoints in humans, three were randomized, placebo-controlled trials available only as abstracts.^[23,26,27] The remaining reports included two placebo-controlled trials that used similar methods and produced similar results^[24,25] and three noncontrolled clinical studies.^[21,22,28]

Agarwal

The first and largest (observational) study that was reviewed was performed by Agarwal^[21] in 5000 patients age 35–65 years with hyperlipidemia and evidence of ischemic heart disease. Sixty-three percent of the patients had diabetes mellitus. The study patients prepared aloe vera as a bread by mixing 100 g of fresh flesh gelatin from the aloe vera plant, 20 g of husk of isabgol (psyllium husk), and wheat flour. The bread was to be consumed twice daily. At the end of the study, more than 93% of the patients had returned to normal ranges (although not to values now considered normal) for both diabetes and lipid markers. However, compliance, formulation, and laboratory measurements were not adequately controlled or reported, so it is difficult to interpret and determine the clinical applicability of the study results.

Ghannam et al

Ghannam et al.^[22] studied five otherwise healthy, non-insulin-dependent patients with diabetes mellitus who admitted to once using aloe vera latex. After a run-in period with no treatment of 2–24 weeks, patients received a half-teaspoonful of aloe latex, in the form of dried resin, daily for 4–14 weeks. Mean ± S.D. fasting serum glucose concentrations decreased in all patients from a baseline 273 ± 56 mg/dL to 151 ± 51 mg/dL after treatment (p < 0.001). Body weight and insulin levels remained unchanged. Three patients were screened for HbA_1c, and a reduction from a mean of 10.6% to a mean of 8.2% was observed. Although these results appear favorable, they should be interpreted with caution because of the very small number of patients included in the study and the variability in administration and duration of treatment.

Nasiff et al

In a study evaluating lipid variables, Nasiff et al.^[23] examined the effect of oral aloe vera extract on lipid metabolism in patients with hyperlipidemia uncontrolled by dietary interventions. Sixty patients between the ages of 40 and 60 years with hypercholesterolemia and hypertriglyceridemia were randomized into three groups of 20 and received either 10 or 20 mL of aloe vera or placebo daily. Lipid profiles were measured at baseline and at 4, 8, and 12 weeks. From baseline, the 10-mL group showed reductions in cholesterol, low-density lipoprotein (LDL) cholesterol, and triglyceride concentrations of 15.4%, 18.9%, and 25.2%, respectively. The 20-mL group showed reductions from baseline of 15.5% in cholesterol, 18.2% in LDL cholesterol, and 31.9% in triglycerides. In addition, patients in the 20-mL group had a 16.9% reduction in apolipoprotein B, another marker for atherosclerosis. In the placebo group, no significant changes in lipid parameters from baseline were noted. No statistical analyses or adverse effects were reported. Contrary to an expected dose-related response, the 10- and 20-mL doses appeared to lower lipid markers by similar degrees.

Yongchaiyudha et al

In a placebo-controlled, single-blind study, Yongchaiyudha et al.^[24] evaluated the effects of oral aloe vera juice in 72 patients age 35–60 years who had high fasting blood glucose and had not been previously treated with hypoglycemic drugs. Patients were equally divided into intervention and control groups. The study group received 1 tablespoonful of investigator-prepared aloe juice twice daily for 42 days, while the control group received a carminative (placebo) mixture. The a priori level of significance was 0.01.

Mean ± S.D. blood glucose concentrations decreased to 141.9 ± 4.1 mg/dL (from 250.4 ± 7.7 mg/dL at baseline) in the intervention group but remained similar at 257.1 ± 7.8 mg/dL (compared with 251.1 ± 8.0 mg/dL at baseline) in the control group (p < 0.01) by day 42. Triglyceride concentrations were lower in the intervention group, at 122.7 ± 5.5 mg/dL (220.3 ± 11.4 mg/dL at baseline) compared with 232.4 ± 9.6 mg/dL in the control group (214.3 ± 10.8 mg/dL at baseline) (p < 0.01). No differences in blood cholesterol levels occurred (p > 0.01).

Bunyapraphatsara et al

Bunyapraphatsara et al.^[25] studied 72 men and women 35–70 years old with diabetes mellitus. The methods, intervention, and treatment duration were identical to those in the study by Yongchaiyudha et al., but all of these patients were being treated with glyburide 5 mg orally twice daily. Mean ± S.D. fasting blood glucose concentrations in the intervention group decreased from 288.1 ± 8.5 mg/dL at baseline to 148.0 ± 4.6 mg/dL by day 42. Mean ± S.D. blood glucose concentrations in the control group remained unchanged, measuring 289.2 ± 7.1 mg/dL at baseline and 289.7 ± 8.1 mg/dL at the end of the study. Triglyceride concentrations at baseline were 264.7 ± 15.2 mg/dL in the intervention group and 223.3 ± 12.2 mg/dL in the control group (p = 0.037). On day 42, mean ± S.D. triglyceride concentrations were 128.3 ± 5.5 and 233.1 ± 13.7 mg/dL for the intervention and control groups, respectively (p < 0.01). No differences in blood cholesterol concentrations were observed (p > 0.01). Although the baseline values for triglycerides were different between the groups, the degree and direction of benefit suggest that the change was clinically significant.

Chalaprawat

Chalaprawat^[26] conducted a crossover, double-blind, randomized, controlled trial comparing aloe vera juice against placebo juice in 16 asymptomatic, normotensive Thai patients newly diagnosed with non-insulin-dependent diabetes mellitus who were not concurrently taking hypoglycemic agents. Participants were divided into two groups (n = 8 in each) receiving aloe vera juice prepared from aloe vera extract or placebo juice, to be administered as 15 mL twice daily (the treatment duration was not reported). In the group that received placebo first, mean plasma glucose concentrations were 252 mg/dL before crossover and 256 mg/dL after crossover. Similarly, mean plasma glucose concentrations were 229 mg/dL (aloe) and 239 mg/dL (placebo) in the group that received the aloe juice first. The changes were not statistically significant (p values not reported). Since only an abstract is available, it is difficult to discern whether the lack of significant change was due to differences in aloe vera preparation or study duration or was a true effect.

Devaraj et al

Devaraj et al.^[27] conducted a randomized, double-blind, placebo-controlled trial of 45 patients with prediabetes to examine the hypoglycemic effects and safety of two aloe products: UP780, a chromone-enriched aloe vera gel fillet powder, and AC952, an aloe vera gel fillet powder standardized to 10% polysaccharide without chromone. Patients received 500-mg tablets of UP780, AC952, or placebo twice daily for eight weeks. Fasting blood glucose and urine glucose concentrations were obtained at baseline and at eight weeks. Significant reductions (p < 0.05) were seen in HbA_1c, fructosamine, insulin, and urinary F2-isoprostanes (a marker of oxidative stress) in the UP780 group, while treatment with AC952 was associated with significantly decreased levels of glucose, fructosamine, and total and LDL cholesterol (actual data not reported). This study is available only in abstract form and did not provide detailed endpoint data. Hence, despite the reported significant decreases in blood glucose and lipid levels, it is difficult to discern the clinical significance of these changes.

Yagi et al

Yagi et al.^[28] reported on 15 patients age 42–55 years whose type 2 diabetes mellitus was uncontrolled on metformin and glyburide. Participants received 2 tablespoonfuls (0.05 g) of aloe vera gel high-molecular-weight fractions (AHM) three times daily for 12 weeks. AHM was prepared from water-washed gel of aloe vera leaves. The end product had <10 ppm of barbaloin, a compound found in aloe exudates with strong stimulant laxative properties.^[10] By the end of the study, fasting blood glucose concentrations had decreased 32% from baseline (baseline concentration of 235 mg/dL estimated from a graph) and had decreased 20% from HbA_1c baseline (baseline of 7.6% estimated from a graph) (p < 0.001 for both endpoints). Triglyceride levels decreased 35% (baseline concentration of 236 mg/dL estimated from a graph) by study end (p < 0.001), although there was no change in total cholesterol levels. The authors described their study methods well, but the lack of a control group and the small sample size are inherent limitations.

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