Cashew nuts are the single seed of the fruit of the cashew tree (Anacardium occidentale). Cashews contain significant levels of copper, iron, magnesium, and manganese, as well as soluble fiber, unsaturated fats, and anacardic acid. Cashews have a lower fat content than other nuts and much of the fat is in the form of oleic acid (an omega-9 fatty acid also found in olive oil); linoleic acid is the other major fatty acid. Cashews contain modest levels of inositol pentakisphosphate, various epicatechins, anthocyanin, myricetin, quercetin, and rhamnetin, all of which have proven or suspected anticancer activities. Cashew compounds have been shown to have antioxidant and anti-inflammatory properties. Habitual cashew consumption does not in and of itself appear to lead to weight gain.
Cancer-related effects of eating cashews
Anacardic acid has been shown to have some chemopreventive properties. Anacardic acid has also been found to sensitize human cancer cells to the cytotoxic effects of radiation treatment. However, anacardic acid is concentrated in the inedible shell of the cashew. No population studies have been performed to assess any possible association between cashew consumption and risk of breast cancer. Cashew nuts contain relatively high levels of copper, which could contribute to angiogenesis and metastasis of breast cancer, especialy in women with inflammatory breast cancer (IBC) or triple negative (ER-/PR-/HER2-) disease.
Cashew nuts are kidney-shaped seeds in hard shells that cling to the bottom of the cashew apple ( the fleshy, red or yellow, pear-shaped fruit of the cashew tree), a native of Brazil. While cashew apples and their juice are consumed in Brazil and the Caribbean, they are very astringent and therefore more often used for jams, pickles, chutney, and wine. The interior of cashew shells contain a caustic resin (used commercially to make varnishes, plastics and insecticides) that must be removed before the nuts can be safely consumed. The leading producers of cashews for export to the U.S. are India, Vietnam, Brazil, and parts of Africa.
Note that while we are continually searching for new evidence specifically concerning this food, there is not much interest in it among breast cancer researchers, so few studies are available.