Dear Lucy: Avocados are an expensive fruit for a student budget, which is why whenever I misjudge an avocado and open up an unripe one, I’m tempted to eat it anyway, even though it tastes awful. But is it true that unripe avocados are toxic to humans? —Omnivore’s Dilemma
Dear OD: Lucy, also an avocado lover—and one with still-vivid memories of trying to eat well on a student budget—took your question straight to MIT Medical nutritionist Anna Jasonides, R.D. To Lucy’s relief, Jasonides was quick to reassure her that as far as humans are concerned, the only possible harm in avocados may be in the number of calories they contain (however, she’s quick to add, most of those calories come from good, monosaturated fats).
On the other hand, Jasonides says, if you were a bird, horse, or other domestic animal, you’d definitely want to avoid the fruit of unripe avocados, along with avocado pits, leaves, and stems, all of which contain a fatty acid derivative called “persin.” Consumed in sufficient quantities, persin can cause illness or death in many birds and domestic mammals, but it does not appear to be harmful to non-allergic humans.
As you point out, however, the best reason to avoid unripe avocados is that they taste terrible! Therefore, Lucy would like to encourage you to hone your avocado-selecting skills so as to avoid the type of misjudgment that has, in the past, led to the horrible dilemma you describe.
According to the California Avocado Commission, the best way to judge an avocado’s ripeness is to gently squeeze the fruit in the palm of your hand. Fruit that is ready to eat will be firm but yield to gentle pressure. Since ripe avocados are rarely found in grocery stores in the northeast, delayed gratification and advance planning is crucial. To hasten ripening, place hard fruit in a plain brown paper bag and store at room temperature until it passes in the “squeeze test” (usually two to five days). Adding an apple or banana to the avocado bag speeds the process further, because both fruits give off ethylene gas, a ripening reagent.
Hope this helps. Guacamole, anyone? —Lucy