Scientific Name: Avocado
Other Names: ASU, Abokado, Ahuacate, Alligator Pear, Laurus persea, Persea species

Who is this for?

Uses

Chemicals in avocados may help to lower cholesterol. 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.

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 refrigerated and stored for no longer than 6 months to 8 months.

In addition, avocado oil contains 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, though, this effect has not been proven in well-controlled human studies.

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. Topically, avocado leaves may be applied to relieve toothache. An extract of avocado leaves may have some antiseizure activity as well as causing blood vessels to relax. None of these possible effects has been proven by controlled studies in humans, however.

Precautions

A chemical known as persin is in the bark, leaves, and wood of the avocado. Persin can sicken animals, birds, and fish. It reduces milk production and destroys breast tissue in cattle and other animals that eat avocado leaves. In laboratory studies, persin has been shown to have a similar destructive effect on mice. Very high doses may affect the muscles around the heart, as well. Persin passes into breast milk, but its effects on newborn animals are not known. The effects of persin for humans is also unknown. Therefore, all individuals — especially pregnant women, new mothers, and small children — should avoid ingesting parts of the avocado other than the fruits or supplements made from them.

No adverse effects have been reported from eating avocado fruits, and even large amounts of avocado eaten as food have not been associated with any significant problems for humans. However, very little information is available on how large amounts of avocado might affect a pregnant woman, a breast-feeding mother, a developing fetus, an infant, or a small child. Therefore, supplemental use of avocado is not recommended during pregnancy, while breast-feeding, or during early childhood.

What side effects should I watch for?

In a condition known as “latex-fruit syndrome” individuals who are allergic to latex or to tropical fruits such as bananas, figs, or kiwi fruit may also be allergic to avocado. A common enzyme contained in tropical fruits and also in latex is believed to be responsible for the allergy. Rarely, individuals suffer severe allergy symptoms that can be life-threatening. Also rarely, an asthma-like condition has been associated with allergies to avocados and related plants. More commonly, individuals who are allergic to avocados and related plants may experience:

• Itching
• Nausea
• Runny nose
• Vomiting
• Watery eyes

No side effects have been attributed to using avocado or avocado oil in the amounts usually found in foods. In higher doses, they may have laxative effects that could cause mild diarrhea.

What interactions should I watch for?

In one published case report, a very large amount of avocado was suspected of interfering with the blood-thinning effect of the drug warfarin. Although the risk appears to be small, when supplemental avocado is taken with antiplatelet or anticoagulant drugs, the effect of the drug may be decreased and blood clots may occur.

• Antiplatelets include clopidogrel (Plavix) and Ticlid
• Anticoagulants include heparin and warfarin

Aspirin can delay blood clotting, but chemicals in avocado may increase the ability of the blood to clot. If avocado and aspirin are taken at the same time, there is a slight risk that aspirin’s anti-clotting effect may be lessened and blood clots may occur.

Taking any oil by mouth may interfere with the body’s absorption of drugs, herbal products, or nutrients. While no reports of such interference have been associated with taking avocado oil, allowing at least 2 hours between taking medications or eating and taking avocado oil by mouth should minimize any potential interference.

Some interactions between herbal products and medications can be more severe than others. The best way for you to avoid harmful interactions is to tell your doctor and/or pharmacist what medications you are currently taking, including any over-the-counter products, vitamins, and herbals. For specific information on how avocado interacts with drugs, other herbals, and foods and the severity of those interactions, please use our Drug Interactions Checker to check for possible interactions.

Should I take it?

Avocado is a familiar part of the diet in Central America and South America, where the round or pear-shaped fruits are eaten raw, used for a spread, or made into a dip commonly known as guacamole. Avocados are native to the Americas with three main types originating in Guatemala, Mexico, and the West Indies. The fruits of the Guatemalan variety take 12 months to 18 months to mature. They have dark green or black rinds that are very bumpy and thicker than other varieties. Avocados from Mexico are smaller, they ripen in less time — typically 6 months to 8 months — and they have smoother, thinner skins. West Indian avocados have smooth, lighter green skins. The largest variety, each ripe West Indian avocado can weigh up to three pounds. When they are ripe, all varieties of avocado have a wide layer of soft, oily, yellow-green pulp surrounding a single large seed. As much as one-quarter of the fruit’s weight is in the seed, and up to another one-third is composed of monounsaturated oil. Because avocado oil spoils quickly, however, it should be kept refrigerated for no longer than about 6 months.

Avocado trees are large, wide, rapidly-growing evergreens that can grow as tall as 80 feet. In commercial orchards, the trees are pruned to keep their height manageable for harvesting fruits. The wood is easily broken and the roots are relatively shallow, so the trees do not survive well in areas with a lot of wind. Although they need high humidity, avocados also cannot stand swampy locations. And most do not tolerate freezing temperatures for very long. Therefore, they grow best in higher elevation subtropical areas with lots of sunlight.

In the U.S., avocados are cultivated commercially in California, Florida, and Hawaii. Although wild avocado trees take much longer to produce fruits that can be eaten, cultivated trees begin to bear fruits after about 3 years. Avocado trees usually reach full production at 5 years to 8 years and remain productive for a century or longer. Small greenish-white flowers that bloom in long clusters are followed by groups of two or three avocado fruits. Avocados reach full size on the tree, then they are picked by hand and allowed to ripen. Depending on conditions, an average size tree produces 100 to 400 avocados per year.

Compared to other fruits and vegetables, avocado fruits are relatively high in protein and fiber. They also contain significant amounts of iron, lutein, potassium, vitamin C, and vitamin E. In fact, avocados have higher contents of lutein and potassium than any other fruit. At 50 calories to 60 calories per ounce, though, they are quite high in calories. However, the high fat content of avocado (5 grams to 10 grams per ounce) may increase the absorption of fat-soluble nutrients, such as vitamin E and lutein, which are contained in avocado. Avocado oil is used for cooking and in skin care and hair care products. A liquid obtained from the seeds has been used as ink.

Dosage and Administration

For treating osteoarthritis (OA), a combination of one-third avocado unsaponifiables and two-thirds soybean unsaponifiables has been used. In most studies, individuals took either 300 mg or 600 mg of the combination (known as ASU) per day. Both doses appeared to relieve symptoms of OA, but the higher dose did not provide more effects or cause more side effects than the lower dose.

Summary

Avocado, avocado oil, and a combination of avocado oil and soy oil known as ASU may help to lower cholesterol. They may also provide some relief for osteoarthritis symptoms.

Risks

Many parts of the avocado tree may contain harmful amounts of persin, a chemical that can destroy breast tissue and may damage the heart. Ingesting avocado bark, leaves, roots, or any part of the avocado other than its fruits is strongly discouraged.

Side Effects

Individuals who are allergic to latex or to other tropical fruits, such as bananas or kiwi, may also be allergic to avocado. Large doses of avocado or avocado oil may have mild laxative effects.

Interactions

Avocado may decrease the effects of blood-thinning drugs such as warfarin and aspirin. The oil in it may interfere with the absorption of drugs or some nutrients from food, but fat-soluble nutrients may be absorbed better when taken with an oily food such as avocado.

Posted February 6, 2007

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Posted February 6, 2007

Note: The above information is not intended to replace the advice of your physician, pharmacist, or other healthcare professional. It is not meant to indicate that the use of the product is safe, appropriate, or effective for you.

In general, herbal products are not subject to review or approval by the U.S. Food and Drug Administration (FDA). They are not required to be standardized, meaning that the amounts of active ingredients or contaminants they contain may vary between brands or between different batches of the same brand. Not all of the risks, side effects, or interactions associated with the use of herbal products are known because few reliable studies of their use in humans have been done.

This information is provided for your education only. Please share this information with your healthcare provider and be sure that you talk to your doctor and pharmacist about all the prescription and non-prescription medicines you take before you begin to use any herbal product.

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