Understanding Toxins in Avocado Seeds

Avocados are a great part of a healthy diet, but what about their seeds or pits? They contain a small amount of a natural toxin called persin [(R, 12Z,15Z)-2-Hydroxy-4-oxohenicosa-12,15-dienyl acetate]. Persin is an oil-soluble  compound found in the leaves and bark of the avocado plant as well as the pits. It acts as a natural fungicide. While the amount of persin in an avocado pit isnt enough to harm a human, avocado plants and pits can harm pets and livestock. Cats and dogs may become slightly ill from eating avocado flesh or seeds. Because the pits are so fibrous, they also pose a risk of gastric obstruction. The pits are considered toxic to birds, cattle, horses, rabbits, and goats. Avocado pits also cause problems for people who are allergic to latex. If you cant tolerate bananas or peaches, its best to steer clear of avocado seeds. The seeds contain high levels of tannins, trypsin inhibitors, and polyphenols that act as anti-nutrients, which means they reduce your ability to absorb certain vitamins and minerals. In addition to persin and tannin, avocado seeds also contain small quantities of hydrocyanic acid and cyanogenic glycosides, which can produce toxic  hydrogen cyanide. Other types of seeds containing cyanogenic compounds include apple seeds, cherry pits, and citrus fruit seeds. However, the human body can detoxify small amounts of the compounds, so theres no risk of cyanide poisoning to an adult person from eating a single seed. Persin may cause apoptosis of some types of breast cancer cells, plus it enhances the cytotoxic effects of the cancer drug tamoxifen. However, the compound is soluble in oil rather than water, so further research is needed to see whether an extract of the seed can be made into a useful form. The California Avocado Commission recommends people avoid eating the avocado seed (though of course, they encourage you to enjoy the fruit). While its true there are many healthful compounds in the seeds, including soluble fiber, vitamins E and C, and the mineral phosphorus, the consensus is more research is needed to determine whether the benefits of eating them outweigh the risks. How to Make Avocado Seed Powder If you decide to go ahead and try avocado seeds, one of the most popular ways to prepare them is to make a powder. The powder can be mixed into smoothies or other foods to disguise the bitter flavor, which comes from tannins in the seed. To make avocado seed powder, remove the pit from the fruit, place it on a baking sheet, and cook it in a preheated oven at 250 F for 1.5 to 2 hours. At this point, the skin of the seed will be dry. Peel away the skin and then grind the seed in a spice mill or food processor. The seed is strong and heavy, so this is not a task for a blender. You can grate it by hand, too. How to Make Avocado Seed Water Another way to use avocado seeds is for avocado seed water. To make this, mash 1-2 avocado seeds and soak them in water overnight. The softened seeds can be pureed in a blender. Avocado seed water may be added to coffee or tea or to a smoothie, much like avocado seed powder. References Butt AJ, Roberts CG, Seawright AA, Oelrichs PB, MacLeod JK, Liaw TY, Kavallaris M, Somers-Edgar TJ, Lehrbach GM, Watts CK, Sutherland RL (2006). A novel plant toxin, persin, within vivo activity in the mammary gland, induces Bim-dependent apoptosis in human breast cancer cells. Mol Cancer Ther. 5 (9): 2300–9.Roberts CG, Gurisik E, Biden TJ, Sutherland RL, Butt AJ (October 2007). Synergistic cytotoxicity between tamoxifen and the plant toxin persin in human breast cancer cells is dependent on Bim expression and mediated by modulation of ceramide metabolism. Mol. Cancer Ther. 6 (10).