Aloe vera is a succulent plant that grows in arid countries – Africa, India etc, and is thought to originate in the Sudan. It has been used since Egyptian times as a medicinal plant, and even today the gel that comes out when you break a leaf in two is often applied to skin burns or other skin problems. Aloe vera juice was often used as a laxative until the FDA pulled the plug in 2002 because there was a lack of studies on how safe it was for human consumption. In a UK study aloe vera gel was found to be effective in treating some patients with ulcerative colitis (inflammatory bowel disease).
The National Toxicology Program (the NTP is a federal, interagency program run at the NIEHS, whose aim is to study environmental substances that might be cause for concern to humans) studied Aloe vera after the National Cancer Institute nominated Aloe vera for further study.
To summarise their study, the National Toxicology Program found during a 2 year study that male and female rats showed an increase in intestinal tumours. However, there was no such correlation in mice.
Does this mean aloe vera is bad for humans? Well, not necessarily. Firstly, we need to make the distinction between rats and humans. While there are a lot of physiological similarities (which is why we use them for research purposes), there is clearly a big difference which means no definitive conclusions can be made.
Also the study by NTP used a non-decolorized whole leaf extract of Aloe vera. Many companies produce aloe vera juice using a charcoal filtration system. This filtering removes the color as well as some components from the juice. One such component that may be removed from this “decolorized” juice is a group of chemicals called Anthraquinones. These chemicals have laxative properties, but, some have been shown to be carcinogenic in previous studies.
A short summary of the NTP states:
“The two-year NTP study on consumption of non-decolorized whole leaf extract of Aloe vera found clear evidence of carcinogenic activity in male and female rats, based on tumors of the large intestine. From what we know right now, there is nothing that would lead us to believe that these findings are not relevant to humans. However, more information, including how individuals use different types of Aloe vera products, is needed to determine the potential risks to humans.”
What we think:
Companies selling aloe vera juice need to invest their money in further studies. Clearly there is some doubt as to not only the potential health benefits of drinking aloe vera juice, but also possible health risks. The claims by these companies that aloe vera juice can cleanse the digestive system or treat constipation needs to be backed up by medical studies to not only show they are safe, but also that they do what the advertisers claim.
Also, if aloin (a chemical belonging to the anthraquinones) is the reason aloe vera juice has laxative qualities, then people should be made aware that this groups of chemicals may be carcinogenic.
Should you stop drinking aloe vera juice?
Well, that is a decision for you and your health care professional. If aloin is the carcenogenic factor in Aloe vera you should certainly not drink aloe vera that contains this substance. Unfortunately there may be no way of knowing as manufacturers are not required to state concentrations of aloin on the label.