Soothing sunburn with cooling aloe
The Irish Times
Health Supplement, p. 13
22 July 2008
DOES IT WORK? Aloe and skin problems
Anyone fortunate enough to find the sun this summer, but unfortunate enough to get sunburned, may have looked to aloe gel for relief. The gel is made from the succulent centre of Aloe vera leaves. This cactus-like plant is native to hot, dry climates but is now cultivated in many parts of the world. Aloe juice (or aloe latex or aloes) is made from the milky liquid that flows from a shallow cut in the leaves. Correctly made, aloe gel and aloe juice contain completely different compounds. However, some producers crush the whole aloe leaf giving products containing both parts of the leaves.
Aloe gel is widely used in cosmetics and skin treatments, while aloe juice is recommended for oral consumption. The juice is recommended for several conditions, most commonly to relieve constipation. The topical (external) use of aloe must be considered separately from oral (internal) use as the effects are very different.
Evidence from studies
Aloe gel contains complex sugars which trap a lot of water and thus have a soothing and moisturising feel on the skin. Chemical analyses have found a number of compounds which reduce swelling and irritation, along with amino acids, vitamins and many other compounds. While aloe gel has been used for thousands of years and is produced commercially on a large scale, surprisingly little research on its effectiveness has been published. Most of the controlled studies support its topical use to promote skin healing with relatively mild burns and wounds. However, studies applying aloe gel to more serious wounds like pressure ulcers and radiation burns did not result in faster healing.
The research on aloe’s internal use is even more sparse. Chemical analyses of aloe juice show that is contains chemicals called anthraquinones. When taken orally, these act as laxatives to relieve constipation. However, they work by irritating the intestines to cause them to contract and secreting water and electrolytes into the intestines. This causes bowel movements, but concerns have been expressed that the effect can easily become too irritating. Cases have been reported of severe abdominal discomfort, electrolyte imbalances and kidney problems. In 2002, the Food and Drug Administration in the US ordered aloe products sold as over-the-counter laxatives to be removed from the market. This occurred after manufacturers had failed to provide evidence that the laxatives were safe.
Problematic aspects
Internal use of aloe juice carries a number of risks with very little evidence to support its alleged benefits. Less dramatic and safer laxatives are readily available. Internal use is especially problematic for anyone who is pregnant because aloe juice can stimulate the uterus as well as the intestines. Those with heart conditions should not taken aloe orally because of electrolyte disturbances. Given the variety of ways aloe products are prepared, aloe gel may contain some juice and therefore should not be used internally either.
When applied to the skin, aloe gel is tolerated well by most people. Some participants in the clinical trials experienced burning, itching and other symptoms of an allergic reaction. While these effects went away once use was stopped, an allergic reaction on top of sunburn or another wound would be very irritating. Given its widespread use, people should determine ahead of time whether or not they are allergic to aloe gel.
Recommendations
The long tradition of using aloe gel to treat relatively mild skin irritation, wounds and sunburn has been confirmed by a small amount of research. Its oral use cannot be recommended because of the risk of side effects. However, the popularity of aloe gel has led to many products of varying quality. Picking a high-quality product can be difficult. The International Aloe Science Council is a non-profit trade organization that certifies those aloe products made according to industry standards. Their website publishes a list of certified products which are also permitted to display a seal of approval on their labels.
Bioethics Ireland 