PDF
(Download)
|
- Aloe Vera (Aloe vera, Xanthorrhoeaceae)
- Diabetes
- Systematic Review/Meta-analysis
|
Date:
10-14-2016 | HC# 091661-554
|
Re: Aloe Vera Shows Promise in Lowering Blood Glucose and Reducing Other Symptoms of Prediabetes
Zhang
Y, Liu W, Liu D, Zhao T, Tian H. Efficacy of aloe vera supplementation on
prediabetes and early non-treated diabetic patients: a systematic review and
meta-analysis of randomized controlled trials. Nutrients. June 23, 2016;8(7).
pii: E388. doi: 10.3390/nu8070388.
Diabetes is characterized partly by elevated
blood glucose and is a serious disease that may lead to potentially devastating
health complications. Standard medications for diabetes often cause adverse
side effects; thus, botanicals may be an effective and less expensive option
for lowering blood glucose. Aloe vera (Aloe
vera, Xanthorrhoeaceae) is used to treat many health concerns, but the
research on its potential use for diabetes is conflicted. This systematic review and
meta-analysis focused on randomized
clinical trials (RCTs) investigating potential hypoglycemic activity of aloe
vera.
The authors searched PubMed, Embase, and Cochrane
Central Register of Controlled Trials, from each database's origin to January
28, 2016. The search terms used were extensive, including
"hyperglycemia," "impaired glucose tolerance,"
"diabetes mellitus," and "aloe vera," among others.
Publications in any language were considered. The American Diabetes Association
and World Health Organization criteria for prediabetes and type 2 diabetes
mellitus were used. Studies included were RCTs, with or without lifestyle
interventions, used aloe vera alone, included patients that were not using
hypoglycemic medication and did not have heart disease or other serious health
problems, and had glucose and/or lipid status as primary outcomes. The studies
were evaluated on quality, with the terms "adequate, inadequate, and
unclear," to describe randomization, allocation concealment, blinding, and
intention-to-treat (ITT) analysis.
The search yielded 282 publications and was
narrowed down to five RCTs, published from 1996 to 2016, with 415 patients. It
was found that of the five studies, two reported randomization methodology, and
no RCTs had adequate blinding. Three RCTs had adequate patient withdrawal and
dropout data, and ITT analysis occurred in one study. Patients were overweight
or obese as reported in four RCTs, and study length was six to 12 weeks.
There was significant heterogeneity for fasting
blood glucose in patients across the five RCTs (P<0.00001). Aloe vera
performed better than placebo in reducing fasting blood glucose concentrations
(P=0.02). No effect was noted on insulin concentrations, but heterogeneity was
reported in the two RCTs with this outcome (P<0.00001). Glycated hemoglobin
(HbA1c, a long-term glucose metric) was measured in two RCTs and was
significantly decreased by aloe vera usage (P<0.00001) with no significant
heterogeneity.
Of the RCTs, four investigated aloe vera in
comparison to placebo for triglyceride and total cholesterol (TC) concentrations.
It was found that aloe vera was more effective than placebo in decreasing
triglyceride (P=0.0001) and TC concentrations (P<0.00001); however,
heterogeneity in both metrics was observed (P<0.00001 for both). Also, aloe
vera was found to better increase high-density lipoprotein (HDL) cholesterol (P=0.04)
and decrease low-density lipoprotein (LDL) cholesterol (P<0.00001) as compared
with placebo. Both outcomes had significant heterogeneity (P=0.0008 and
P<0.00001, respectively).
In summary, the authors conclude that aloe vera
treatment impacted fasting blood glucose concentrations, HbA1c, and
triglyceride, TC, and LDL and HDL cholesterol concentrations, despite heterogeneity
across RCTs. Discussed possible mechanisms include potentiation of glucose
transport, attenuation of cholesterol gut absorption, and modulation of gene
expression. Stated limitations include the finite RCT sample size, discrepancy
of patient background, publication bias, variation in form and dose of aloe
vera (studies included used capsules, powder, or juice), and lack of available
data for certain outcomes. Additionally, some methodology was not reported. Larger
and more rigorous trials to establish the efficacy and safety of aloe vera in
this population are recommended.
—Amy C. Keller, PhD
|