Studies suggest aloe vera has antidiabetic properties, but is the research sound?
Pre-diabetes and metabolic syndrome which follows it are parts of interrelated common clinical disorders that are accompanied by symptoms of obesity, insulin resistance, glucose intolerance, lipid abnormalities, impaired fasting glucose, and impaired glucose tolerance. Studies have reported that approximately 5-10% of the pre-diabetic population would suffer from diabetes. Timely interventions can preserve beta cells and improve their performance. It is assessed that 382 million people worldwide are living with diabetes mellitus, expected to rise to 592 million people in less than 25 years. Diabetes is a progressive and chronic course, and one of the leading causes of disability, morbidity and mortality. The personal and economic burdens of diabetes mellitus are devastating, with a cost of $245 billion in 2012. By 2030, global expenditure is anticipated to reach $490 billion. Aloe vera, with a common name Aloe barbadensis, belongs to the family Liliaceal and has over 200 species worldwide. For many centuries it has been used in the health and cosmetic sector. Studies have shown that Aloe vera extracts have a preventive effect against insulin resistance and lipid lowering effect. Previous studies by Ngo et al in 2010 concluded that oral aloe vera may be effective for treatment for diabetes.
The purpose of this study, which was a meta-analysis, was to summarize and evaluate the evidence from randomized clinical trials involving the use of aloe vera as a hypoglycemic supplement. The literature was conducted by (Y.Z and W.L) with any inconsistencies reviewed by (D.L). The inclusion criteria was that it was a) RCT, b) those who incorporated lifestyle changes or not, c) studies involving the use of aloe vera as part of a combination product or treatment, d) no history of any hypoglycemia medication use, e) no history of other comorbid disease. Review manager software 5.2 by Cochrane was used for the statistical analysis. The primary outcomes were glucose metabolism such as fasting blood glucose (FBG), insulin and glycosylated hemoglobin A1C; secondary outcomes included lipid profile such as triglycerides, total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C). The changes in FBG were evaluated in five studies which included 328 cases. Aloe vera was superior to placebo in reducing FBG levels (P=0.02). Analysis of aggregated data showed a significant reduction in HbA1c (P<0.00001).
Another study, which was a double blind randomized controlled trial, was done at Birjand University of Medical Science. The purpose was to investigate the effects of two different doses of aloe vera extract and to determine the least time needed to improve glucose and lipid profile levels in prediabetes subjects. It involved 72 from the inclusion criteria who were further divided into 3 groups. The groups (n=24): aloe vera groups (AL300, AL500) and placebo group (PL). AL300 and AL500 received 300 and 500 mg of aloe vera extract twice a day whilst the PL group received a capsule containing micro crystalline cellulose. All participants took capsules after breakfast and after dinner for eight weeks. Participants visited the research center to give blood samples at the end of fourth and eighth weeks of study. Subjects were advised not to change their diet or daily routine.
Statistical analysis was done on SPSS using ANOVA and Bonferroni tests. The mean age was 52.5 ± 0.8 years and 70% of them were women. No adverse effect was reported and capsules were well tolerated with no complaints. FBG levels in AL300 and AL500 groups decreased significantly in four weeks (P= 0006 and P=0.001) and eight weeks (P=0.002, P< 0.001) respectively. FBG levels had no change in the control group during the study. HbA1c also had a significant decrease in both groups (P=0.042 and P=0.011) respectively compared to the control group. Levels of CHOL-C, LDL-C and TG in eight weeks after weeks of receiving 500 mg capsules of Aloe vera extract showed a significant decrease compared to the control group. HDL-C level for both 300 and 500 mg of aloe vera both showed significant reduction.
For the meta-analysis data extraction study, it was found that there were significant differences between groups for most parameters. The limited evidence reveal a statistically significant difference in reducing serum FBG and HbA1c levels favoring aloe vera over placebo. Also aloe vera reduced levels of triglyceride, TC and LDL-C and increase HDL-C. There were, however, a number of limitations such as a small number of trials and the backgrounds of patients being varied. This resulted in a low statistical power. Also insulin or glycosylated HbA1c data was not available in majority of the studies. In conclusion, aloe vera extract in pre-diabetic patients can significantly regulate levels of FBG within four weeks and eight weeks for lipid profile.
- Pre- diabetes is a serious global epidemic that increases the risk of getting type 2 diabetes by fivefold and the probability of cardiovascular disease by two times.
- Aloe vera has applications in health and cosmetic products as well as anti-tumor, antioxidant, anti- inflammatory and laxative properties.
- Aloe vera could be an interesting supplement strategy to alleviate impaired serum glucose level and lipid profile. More and better designed studies need to be done.
Alinejad-Mofrad, Samaneh et al. “Improvement of Glucose and Lipid Profile Status with Aloe Vera in Pre-Diabetic Subjects: A Randomized Controlled-Trial.” Journal of Diabetes and Metabolic Disorders 14 (2015): 22. PMC. Web. 11 July 2016.
William Dick R et al. “Reduction of Fasting Blood Glucose and Hemoglobin A1C Using Oral Aloe Vera: A Meta-Analysis”. The Journal of Alternative and Complementary Medicine 22(6) June 17 2016. Web. 11 July 2016.
Zhang Yiyi et al. “Efficacy of Aloe Vera Supplementation on Prediabetes and Early Non- Treated Diabetic Patients: A Systematic Review and Meta – Analysis of Randomized Controlled Trials”. Diet and Metabolic Dysfunction. (2016). Web 11 July 20116.