According to WebMD (ew, I know) Aloe Vera contains lectins and aloin, which is a potential carcinogen but only in rats. Aloe as a human carcinogen hasn't been proven, but I suspect that the amount of aloin the rats were receiving were well above and beyond the dose you would find if you harvested your own aloe vera or bought AV juice/gel.
What lectins does Aloe Vera contain? I don't think I've ever heard of anyone cooking aloe or using it in cooking, so it's safe. If someone could shed light on this, that woul dbe great. Aloe is supposed to be a potent anti-inflammatory, especially for people with GI issues.
I found this interesting tidbit on an IBS forum:
Aloe vera is a wonderful short term healer for the gut, but we are warned against its long term use because it is a laxative & will turn the intestinal walls form a healthy pink to black. Please read on. Aloe Vera & I.B.S Because aloe is well-known as a gentle external treatment for minor burns and skin irritations, it's easy to assume that it would be safe for use internally as well. This is not necessarily true. Even though aloe vera is a plant, and thus "natural", it is still classified by the FDA as a Class 1 harsh stimulant laxative. There are substances called anthroquinones and anthrones in aloe, which produce a laxative effect by increasing colonic peristalsis and intestinal water content, by opening chloride channels of the colonic membrane to cause a net reduction of liquid absorption by the colon.In plain English, this means that aloe causes faster and stronger contractions of the colon - something that people with IBS are already overly prone to, and which can cause violent abdominal cramps, painful spasms, and diarrhea. The safety of aloe is another concern. All anthranoid laxatives (not just aloe, but senna and cascara sagrada as well) can cause melanosis coli, cathartic colon, and possibly increase the risk of colonic cancer. (In fact, genotoxicity studies show that aloe-containing laxatives pose cancer risks to humans even when used as directed.) Melanosis coli, normally a benign condition, is characterized by black pigmentation of the colonic wall, and is almost always attributable to anthranoid laxatives such as aloe, cascara, or senna. Melanosis coli usually develops 9 months after initiating the use of anthranoid laxatives, and typically disappears just as quickly after the drug is discontinued. In severe cases, however, it may reduce bowel function and make constipation worse.
In advanced cases of melanosis coli, the inside lining of the colon becomes pitch black instead of the normal light pink. Cathartic colon is the anatomic and physiologic change in the colon that occurs with chronic use of stimulant laxatives such as aloe (chronic use is defined as more than 3 times per week for at least 1 year). Signs and symptoms of cathartic colon include chronic constipation, bloating, a feeling of fullness, abdominal pain, and incomplete fecal evacuation. Radiologic studies of a patient with cathartic colon will show: an atonic colon (the colon lacks the normal muscle tone) and a redundant colon (the laxative use has stretched out the colon to twice the normal length, and the bowel has developed redundant coils of bowel tubing that loop back and forth in the abdominal cavity). As if this isn't bad enough, chronic use of aloe can also lead to serious medical consequences such as fluid and electrolyte imbalance, steatorrhea, gastroenteropathy, osteomalacia, and vitamin and mineral deficiencies. When aloe is discontinued, radiographic and functional changes in the colon may only partially return to normal because of permanent drug-induced neuromuscular damage to the colon. What's really scary about aloe is that it's a very common ingredient in all sorts of liquid vitamins, energy boost drinks, and other health supplements, and these product labels won't note that aloe is a laxative. Aloe is even specifically marketed to people with IBS as a "digestive aid", or "soothing to the bowel", with an emphasis on the fact that it's an all-natural plant ingredient, which again just hides the fact that it is without a doubt a harsh stimulant laxative.
At this point, products derived from aloe gel and intended for internal use have not been proven effective against any disease or disorder, but the dangers seem clear. I would err on the side of caution and avoid aloe altogether, as it seems to me that its well-established risks far outweigh any potential (and as yet unproven) benefits. ---------------------------------------------
There are many products now on the market which contain Aloe, & I believe the last count for actual companies that bottle the juice from the plant, or buy it in bulk is now around 287 world wide!There is no doubt whatsoever that when used topically on burns, scalds,rashes & even sun-burn, Aloe has NO equal. It soothes & helps the area affected to heal rapidly, & because of those qualities I always have a plant by the back door for this purpose, but by the evidence now available such as mentioned above, I must ask you this question: Will you be constantly consuming Aloe in any form now knowing of these risks?? I CERTAINLY WILL NOT.
For the normal healthy person, I'd agree that it probably makes no sense to consume aloe because as you say the potential risks likely outweigh any benefits. However, if you have a specific disease which aloe might help cure, then that might change the equation. E.g., if you have active ulcerative colitis, and IF the aloe could help, the benefits might outweigh the risks (because ulcerative colitis sucks):
I have been taking Aloe Vera for two years now. Everyday to promote peristalsis. I have serious IBS/constipation. Now it seems I don't have IBS. I have colonic inertia. The aloe vera helped. But now it does not. I did not know it caused the intestines to become black and was a risk for cancer. How long would a person need to take Aloe to have a risk of cancer? I took the recommended dose of one or two ounces a day.
Some people here need some serious education on aloe vera! There are many constituents of the plant and the con men who sell you whole leaf aloe are screwing you. The inner leaf gel, uncontaminated by the anthraquinones and aloin in the outer leaf will be a Godsend for IBS or any other digestive issue and can be used perpetually without negative side effects or harm! I take aloe every day and it's only beneficial. But, I would never consider that for one minute with "whole leaf" aloe! It's the outer leaf that causes all the problems. There are those who argue for benefits from the outer leaf, but the anthraquinones and aloin in outer leaf of aloe vera are seriously problematic and should be avoided.
Add Manuka honey to the mix and you've get two wonderful things. Make sure your aloe is either fresh or that you know the character of the manufacturer and the quality because the industry as a whole CANNOT be trusted.
There are many solutions and remedies for constipation. One thing you can probably safely assume is that you're deficient in magnesium and you can safely add that very cheap supplement to your diet along with several grams of Vitamin C. 400-1000 mgs of magnesium and 3-6 grams of Vit. C will probably instantly show an improvement with constipation but, of course, constipation is also affected by your diet so search out what things you're eating that negatively affect that and look at foods that will improve that, but one of doctors biggest crimes in this area is not telling their patients that magnesium supplementation might just completely eliminate constipation as a problem.
Regarding Vit. C, unless you're taking Vit. C with lysine (as part of the Pauling Therapy to reverse heart disease) then you should take only a gram of Vit. C at a time because your body will flush out the excess.
If you're a guy and you have any concern about heart disease, then go to PaulingTherapy dot com and look at their recommendations. It's something the medical industry won't tell you because they make too many millions in operations to tell you that you can stop and reverse heart disease with Vit. C, Lysine and Proline. I've seen a substantial improvement with the Pauling Therapy. BTW, don't fall for the "all in one" packages. It's cheaper and your products will last longer (moisture issues) if you buy the three products separately.
I love aloe. If you can tell the difference when you take aloe, you've got a decent product. If you can't, then, either your digestive system is in perfect shape or your aloe is crappy. Don't trust aloe producers. Buy only from companies who'll refund your money if you're not happy. I like the product I take so much, I became a distributor!