* Cashew nut is made up of a fruit in which the kernel is embedded. The real fruit of the cashew is commonly a nut. It is a kidney- or heart-shaped achene, in any normal variety. Cashews are a good source of magnesium, which plays an important role in over 300 enzymatic reactions within the body.these include the metabolism of food and synthesis of fatty acids and proteins. Magnesium is also involved in muscle relaxation and neuromuscular transmission and activity.