Herbs & Supplements

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Uses

Chemicals in avocados may help to lower cholesterol in different ways. First, the fruits contain a relatively high amount of a phytosterol known as beta-sitosterol. Phytosterols are plant chemicals that are similar in shape to cholesterol. They attach to some of the places in the intestines where cholesterol is usually absorbed. Unlike cholesterol, however, very little of the phytosterols is absorbed by the body. Because they block cholesterol absorption, phytosterols force more cholesterol to be eliminated from the body so less cholesterol enters the blood. Lower levels of cholesterol in the blood help to prevent hardening of the arteries and the formation of plaques in blood vessels. Plaques are accumulations of fat and other substances that stick to the inside of blood vessels. Eventually, plaques may lead to blood clots, heart attacks, or strokes.

Additionally, avocados contain large amounts of fatty acids--including linoleic acid, oleic acid, and palmitic acid. Fatty acids are thought to block the production of chemicals that lead to the formation of deposits in the blood vessels. When participants in several studies ate the unsaturated fats in avocado to replace animal fat in their diets, most saw blood levels of triglycerides, total cholesterol, and low-density lipoproteins (LDL or "bad" cholesterol) decrease. In some studies, the levels of high-density lipoproteins (HDL or "good" cholesterol) increased among individuals receiving the avocado diet, but this effect has not been consistent. In studies of laboratory animals, a combination of avocado and soy (ASU) promoted the elimination of cholesterol by the body. Again, however, this effect has not been proven in well-controlled human studies.

Using avocados and avocado oil in place of butter and other fats that come from animal sources may also help to prevent heart disease. Fats are generally classified as saturated or unsaturated according to their chemical structures. Saturated fats are usually solid at room temperature. Mainly derived from animal sources, saturated fats are more likely to form deposits in blood vessels, thereby increasing the chance of having high cholesterol, heart disease, and related conditions. Because the oil from avocado is unsaturated, it is less likely to accumulate in blood vessels. However, avocado oil spoils quickly. It should be stored in a refrigerator for no longer than 6 months to 8 months.

Oil derived from avocados, usually in combination with soy oil, is taken orally to treat osteoarthritis (OA). Known as avocado-soy unsaponifiables (ASU), the combination is commonly one-third the unsaponifiable components of avocado and two-thirds the unsaponifiable components of soy. Unsaponifiable means that the fatty oils do not break down to make soap like many types of fats do. In Europe and Scandinavia, ASU has been available as a prescription drug or nonprescription dietary supplement for several years. In numerous human studies, it has been found to have anti-inflammatory effects. In one study, more participants taking ASU were able to reduce the doses of other medications they needed to control arthritis pain than patients taking placebo (inactive sugar pills). Generally, patients taking ASU reported decreased pain and improved ability to function. In the laboratory, ASU may have helped to repair cartilage by increasing collagen production and decreasing the effects of destructive chemicals that break down cartilage. More study is needed in humans to determine whether ASU can repair structural damage caused by OA.

Oil extracted from the avocado fruit is also applied topically to relieve minor skin irritations. Due to its soft consistency and high oil content, the meat of avocado fruits may also be mashed and applied to the skin to soothe scrapes, sunburn, and minor wounds. In folk medicine, avocado pulp has been used to encourage hair growth, but no studies have proved that it can help to regrow hair. Avocado oil has also been mixed with vitamin B-12 into a cream to treat psoriasis. Although the combination works slowly, it does appear to offer some relief with few side effects.

In traditional use and laboratory research, avocado has shown some other possible medical effects. When fed to rats with chemically induced liver damage, avocado reduced further injury. It also may have helped to repair previous liver damage. In studies, ASU has blocked the production of chemicals that may contribute to diseases of the teeth and gums. In some Central American and South American countries, natives take avocado bark, leaves, and seeds orally to treat diarrhea. An extract of avocado leaves may have some antiseizure activity as well as causing blood vessels to relax. Consuming parts of the avocado tree other than the fruits is discouraged, however. Topically, avocado leaves may be applied to relieve toothache. None of these possible effects has been proven by controlled studies in humans, however.