Aloe vera, a spiky succulent plant native to Africa, has been used medicinally for centuries, although there is limited evidence to support its effectiveness. According to the National Institutes of Health, aloe is used orally to treat constipation, ulcerative colitis, diabetes and other conditions. The World Health Organization cautions that latex, or sap, derived from the lining of the aloe leaf contains bio-active compounds that may have profound effects on the human body.
Aloe Vera
According to a 1999 article in the "British Journal of General Practice," aloe vera is rich in vitamins, minerals, sugars, enzymes and amino acids. Almost 400 species of aloe have been discovered, and extracts of the plant are used all over the world. Aloe gel from the clear viscous pulp at the center of the leaf is typically used in cosmetics and topical preparations. The bitter yellow latex in the leaf's lining contains anthraquinones, including aloin and emodin, thought to be responsible for their strong laxative effects.
Liver Damage
Bio-active compounds in the aloe plant may induce liver inflammation, according to researchers in the "World Journal of Gastroenterology." In 2005 they reported the case of a 57-year-old woman with severe acute hepatitis who had taken aloe vera capsules for four months. Her symptoms subsided after stopping the supplement. Acute hepatitis in a 55-year-old woman resolved after discontinuation of aloe extract, as reported in 2010 in the "Journal of Korean Medical Science." At least three other cases have been described in Korea, the U.S. and Turkey. The Korean researchers speculate that hypersensitivity to aloe, which can be confirmed with an allergic skin test, may explain some of the cases.
Kidney Failure
South African researchers blame toxic compounds in the resin of the aloe plant for at least one case of kidney failure. As reported in the "American Journal of Kidney Disease" in 2002, a 47-year-old man suffered acute renal failure after taking aloe for constipation, necessitating dialysis and a 44-day hospital admission. The investigators believe that the man's concomitant use of a diuretic with high doses of aloe increased potassium and fluid losses, enhancing the plant's nephrotoxic effects. At a South African hospital in 1980, aloe vera use was implicated in six out of eight renal failure cases attributable to over-the-counter remedies.
Interactions with Medications
The NIH cautions that aloe vera ingestion may make medications less effective by speeding intestinal transit time and decreasing drug absorption. If taken with laxative drugs, aloe may worsen dehydration and potassium losses via the intestinal tract. Loss of potassium can also be exacerbated by the use of aloe vera with loop diuretics, such as furosemide. Medications used to treat heart arrhythmias, such as digitalis, may have reduced effectiveness when aloe is used concomitantly. Dangerously low blood sugars can result from taking aloe with glucose-lowering medications.
Other Considerations
The NIH warns that people with allergies to garlic, onions, tulips or other plants in the lily family may have an allergic reaction to aloe. Short-term use of aloe to treat occasional constipation seems safe, but longer than seven days can result in dependency. Oral use of aloe increases risk of electrolyte imbalance in people with heart disease or kidney disease. Diabetics should be cautious with oral ingestion of the plant, especially if taking anti-diabetes medications or other herbs purported to lower blood sugar. The WHO states that aloe should not be used to treat ulcerative colitis, as abdominal spasms and pain can result. As bio-active compounds may pass into the placenta or breast milk, the WHO advises against aloe ingestion for pregnant or breastfeeding mothers.
Federal Regulation
As reported by the National Center for Complementary and Alternative Medicine, aloe vera and other herbal preparations are considered dietary supplements by the FDA. They are not regulated in the U.S. the way medications are. Manufacturers do not have to prove the safety and effectiveness of dietary supplements before they are sold, nor do they have to reveal specific plant species or compounds in the product. In addition, ingredient amounts may be different from what is stated on the label, and the product may be contaminated with harmful substances. The FDA may remove a dietary supplement from the market if its label contains false claims or if it is found to be unsafe.
Recommendations
The National Center for Complementary and Alternative Medicine advises on the safe use of dietary supplements. Tell your health care provider about dietary supplements you are taking. Consult legitimate resources about alternative medicine, such as the National Center for Complementary and Alternative Medicine or the Office of Dietary Supplements.
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