The Peculiar Growth of the Cashew
To understand why cashews are actually seeds, one must first explore how they grow on the cashew tree (Anacardium occidentale). This tropical evergreen tree produces a remarkable, two-part structure. What appears to be the fruit is a brightly colored, pear-shaped or oval pseudo-fruit called the cashew apple. This fleshy part is rich in vitamin C and used for juices in some countries, but is rarely seen internationally due to perishability.
The True Fruit and the Edible Seed
Hanging from the bottom of the cashew apple is the true fruit—a small, kidney-shaped drupe. A drupe is a fruit with a fleshy outer part surrounding a hard shell, enclosing a single seed. The single, edible seed within the drupe's hard shell is what we know as the cashew. The drupe and the cashew apple mature and fall from the tree together.
The Difference Between Culinary and Botanical Nuts
The confusion around the cashew's identity stems from the difference between botanical and culinary definitions. Botanically, a true nut is a hard, dry fruit with a single seed that doesn't split open. Most popular "nuts," including cashews, almonds, and walnuts, are actually drupe seeds. In the culinary world, however, "nut" broadly describes any edible kernel, seed, or fruit in a hard shell. This is why cashews are grouped with other tree nuts despite their botanical reality.
The Complex Path from Tree to Table
Cashews are sold pre-shelled because their raw state contains toxic substances. The shell has urushiol, a caustic oil also in poison ivy, which causes severe irritation. This requires processing before consumption.
Key steps in processing cashews include harvesting mature nuts and apples, separating and sun-drying the nuts, roasting or steaming them to neutralize urushiol, shelling to extract the kernel, and heating again to remove the seed coat.
Comparison: Cashews vs. True Nuts
| Feature | Cashew (Seed) | True Nut (e.g., Acorn) |
|---|---|---|
| Botanical Classification | Seed of a drupe | Hard, dry fruit |
| Growth Method | Develops externally from a cashew apple | Enclosed fully inside a hard shell |
| Shell Composition | Toxic (contains urushiol) | Generally non-toxic |
| Processing Requirement | Must be roasted or steamed to remove toxins | Often shelled without heat treatment |
| Availability | Only sold pre-shelled | Can be sold in-shell |
| Culinary Context | Commonly called a nut | Commonly called a nut |
Nutritional and Culinary Profile
Cashews are nutritious. They are rich in healthy fats, essential minerals like magnesium, copper, and zinc, and protein.
Their texture and mild flavor make them versatile, used as snacks, in cashew butter, creamy sauces, and various cuisines.
Conclusion
While the culinary classification persists, the question, "Are cashews actually seeds?" reveals a fascinating botanical truth. The answer is yes, scientifically. The edible kernel is the seed of a drupe, uniquely grown from a different part of the cashew tree. This process, including toxin removal, adds complexity to this popular food. For more on health benefits, refer to {Link: BBC Good Food https://www.bbcgoodfood.com/health/nutrition/health-benefits-of-cashew-nuts}.
