Cashew Nut, A Nutty Way Of Growing
The sweet, meaty cashew nut is a popular addition to snacks and trail-mixes across the world. But did you know that the cashew nut is actually a potent source of health benefits?
Modern research has found that cashew nuts can help stabilize blood sugar levels, heal wounds, fight against bacterial and parasitic infections, and even kill cancer cells—all while still tasting delicious. What a mighty nut the cashew is!
Anatomy of a nut
Many people think that a cashew is a typical tree nut, like an almond, growing encased in a hard shell which is in turn encased in a fruit of some sort. But it turns out that a cashew nut has one of the strangest growing patterns out there!
The “fruit” of the cashew tree, Anacardium occidentale, is shaped like an apple with a curious green kidney-shaped hook underneath. However, appearances are confusing— the cashew apple “fruit” is actually a thickened part of the stem, and the green hook underneath is the actual fruit! This kidney-shaped fruit is composed of a hard shell, which turns from green to white as it ripens, surrounding a sweet, meaty seed—the cashew nut.
This strange growing pattern is reflected in the name: Anacardium means “outside the heart,” referring to the way the seeds develop outside the heart-shaped cashew apple “fruits.” What a nutty way of growing!
Careful with your cashews!
As mentioned above, the cashew nut ripens inside a hard shell, which produces an oil called cashew shell oil when pressed. This oil has a number of different industrial uses, ranging from lining brakes to waterproofing to making paint. However, extracting the oil is not as straightforward as it sounds, because of one simple fact: the cashew nut is a close cousin of poison oak and poison ivy, and contains the same compound that is responsible for the itchy rash caused by those plants!
In fact, this irritant is present in both the shell and the nut, meaning that the cashew nut must be roasted before eating to destroy the chemical. Unfortunately, roasting the shells dries out the oil, so the oil must be extracted from the raw shells very carefully in order to avoid an itchy cashew rash. So it pays to be careful when eating or processing cashews!
Amazing anacardic acid
Modern research has shown an ever-increasing number of health benefits from eating cashews, ranging from stabilizing blood sugar levels to helping heal wounds. Turns out that many of these benefits are due to the presence of a compound called anacardic acid, found in both the cashew shell oil and the cashew nut itself.
Chemically similar to salicylic acid, the active ingredient in aspirin, anacardic acid has been shown to have a number of medicinally relevant effects 1. It has potent antibacterial effects against a number of pathogenic bacteria, including the ever-worrisome MRSA, and has also demonstrated anti-parasite and anti-inflammatory activity 1. In addition, it appears that anacardic acid has some anti-cancer activity against a number of different cancer types by altering gene transcription and causing apoptosis of cancer cells, especially in hormone-related cancers like breast cancer and prostate cancer 1,2.
Anacardic acid can even help regulate blood sugar levels, possibly by stimulating glucose uptake 3. And, as if that wasn’t enough, anacardic acid has also been shown to hasten wound healing and protect cells against damage 4! So, with this dazzling array of potential health benefits, perhaps it is time to cash in on your cashews!
1. Hemshekhar M, Santosh MS, Kemparaju K, et al. 2012. Emerging roles of anacardic acid and its derivatives: a pharmacological overview.
2. Tan J, Chen B, He L, et al. 2012. Anacardic acid (6-pentadecylsalicylic acid) induces apoptosis of prostate cancer cells through inhibition of androgen receptor and activation of p53 signaling. Chinese Journal of Cancer Reseach 24(4): 275-283.
3. Tedong L, Madiraju M, Martineau LC, et al. 2010. Hydro-ethanolic extract of cashew tree (Anacardium occidentale) nut and its principal compound, anacardic acid, stimulate glucose uptake in C2C12 muscle cells. Molecular Nutrition and Food Research 54(12): 1753-1762.
4. Morais TC, Pinto B, Carvalho KMMB, et al. 2010. Protective effect of anacardic acids from cashew (Anacardium occidentale) on ethanol-induced gastric damage in mice. Chemico-Biological Interactions 183(1): 264-269.