Ever wonder why the eight most common allergens include peanuts and tree nuts? Have you ever assumed that peanuts were a nut? And do you even know what a tree nut is? If you, like I, have ever wondered this, this post explains all the nitty gritty, or rather nutty gritty, on nuts.

What Is a Peanut? And How Does It Differ From a Walnut?

Even though peanut has the word “nut” in the name, it’s not really a nut at all. It’s actually a legume. Peanuts are legumes, which are edible seeds enclosed in pods, and are in the same family as beans, lentils, and peas. Meanwhile, tree nuts, which include but are not limited to, walnuts, cashews, almonds, and pecans, are all produced on trees.

Is That Really the Definition of a Tree Nut?

Well… no. Botanically speaking, nuts are tree nuts, but not all tree nuts are nuts. Some tree nuts are drupes. I know, it’s pretty confusing, so let me explain. Nuts are by definition a hard-shelled pod that contains both the fruit and seed of the plant, a category that includes hazelnuts and acorns. Drupes are actually fruit with a hard stony covering enclosing the seed. Drupes have three layers: an outer layer called the exocarp, a fleshy middle layer called the mesocarp and an endocarp — the hard, woody layer that surrounds the seed. Drupes include peaches, mangoes, pistachios, coconuts, almonds and cashews.

So, If I’m Allergic to Tree Nuts, Does That Mean I Can’t Eat Mangoes or Coconuts?

When it comes to allergens, tree nuts are defined differently. Like I mentioned above, they are any nut or colloquially defined nut that is produced on a tree. They includes true nuts and drupes like almonds, hazelnuts, pecans, walnuts, cashews, chestnuts, coconuts and many, many more. So while having a tree nut allergy means you may not be able to eat coconuts, it doesn’t include mangoes. And having an allergy to walnuts, doesn’t mean you’re allergic to every other tree nut.

All of this matters when it comes to labeling food. If a food or food product contains tree nuts, it may specifically identify that particular nut, or it may just say “tree nuts.” If it’s the latter, because you don’t know which tree nut, it is better to avoid it all together.

What Should I Do If I Think I’m Allergic to Peanuts or Tree Nuts?

Approximately 15 million Americans are affected by food allergies. So it may be possible that you, or someone you know, is living with a food allergy. If you think you have a food allergy, or want to get educated on food allergies in general, here are some practical steps you can take:

• If you believe you have a food allergy, do not diagnose it on your own. All suspected food allergies should always be evaluated, diagnosed and treated by a qualified medical professional. And if you have a food allergy, you will want to avoid the allergen all together.
• Always read the ingredient list before consuming a food or food product. If an allergen is present, it will be listed. Be certain to read and understand labeling statements such as “contain,” “may contain” or “processed in a facility that also manufactures… ” The potential allergen could be in that product.
• If you have any more questions about food allergens, check out our Food Allergies 101 infographic or visit U.S. FDA, FAACT Food Allergy or FARE Food Allergy.

Now that you know the difference between a peanut or tree nut, you flaunt your nut-found knowledge at the next office happy hour or dinner party.

This article was written by Kamilah Guiden and reviewed by Kris Sollid, RD.