The Cashew Apple
The Cashew apple might resemble an illustration you'd find in the Alice and Wonderland novels, or maybe something produced by Willy Wonka on a health drive, but the fact is that these apples are very real, and nutritious. The fruit grows on the Anacardium Occidentale, or the Portuguese translation Caju tree from which the English ‘Cashew’ is derived. It is the bell shaped red and yellow fruit that we source the juice from whereas the ‘C’ shaped kernel delivers us with the delicious cashew nut…a double whammy comparable to a Victoria Secret model with a cherry on top (or in this case, a cashew). Apart from it’s strange exterior, the Cashew Apple is unique because it not only bears two fruits (the apple and cashew nut), but also serves as a remarkably dense source of Vitamin C, protein (considering it’s a fruit) and fibre, all from one tree!
Why have I not heard of Cashew apples before?
Cashew apples are very uncommon here in the UK largely due to the fragility of the skin which is vulnerable to damage during transit, the juice however is far more accessible, you just might not have known about it yet. The juice from the apple is as you’d expect, very sweet and refreshing but with an acidic after taste similar to that of pineapple.
The cashew apple contains 45 times more vitamin C than the average apple, and incredibly 5 times more than an orange! Some forms of processing can damage vitamin C losing some of its benefit, but processing standards are stringent to limit this undesirable consequence.
(The Natural Food Hub, 2009)
Prasertsri et al. (2013) explain that cashew apple juice comprises many nutritional components including vitamin C and branched chain amino acids (BCAAs). However, it is also thought that this unique fruit juice may also positively affect substrate utilisation, particularly fat. This could result in better utilisation of fat as an energy source resulting in fat burning! The ability to burn more fat both improves fat burning and exercise capacity due to fats high energy content per gram (Atwater figure = 9kcal/g).
Role in fat burning
Vitamin C is one of the most widely supplemented vitamins in the world today for several reasons including buffering free radicals, reducing inflammation in blood vessels, maintaining joint integrity, enhancing the absorption of iron and not least of all, for its role in the metabolism of fat. Vitamin C is a known co-factor (partner) to the biosynthesis of carnitine (a well known fat burning agent) which can mobilise fat stores and reduce blood triglycerides.
The predominant BCAA found in cashew apple juice is Leucine, and Leucine has been linked to enhanced energy metabolism and fat burning in C2C12 muscle cells and boosts mitochondrial fat burning function. A study by de Araujo, Falavigna and Rogero, et al. (2006) found that supplementation with Leucine increases hepatic (liver) and muscle concentrations of glycogen (stored glucose) suggesting fat was used for energy ahead of glycogen when training!
Cashew apple juice also contains anacardic acids which of over consumed can result in a burning sensation in the throat, similar to that of pineapple. Anacardic acid was not included in the study by Prasertsi et al. (2013), but despite this are certainly worth considering for their fat burning potential.
Note: In their natural form, cashew apples are high in tannins, which inhibit absorption of iron and reduce the formation of protein. Consequently they are either pressure steamed, candied or sundried to remove the tannins.
So despite the promising findings from this study, it is after all just that…one study, meaning Cashew apple juice could quite feasibly be consumed for its taste, originality and potential fat burning benefits, and could thus soon become the next fat burning trend at your gym!
De Araujo JA Jr, Falavigna G, Rogero MM, Pires IS, Pedrosa RG, Castro IA, Donato J Jr, Tirapegui J. (2006). Effect of chronic supplementation with branched-chain amino acids on the performance and hepatic and muscle glycogen content in trained rats. Life Science. 79: 1343–1348.
Prasertsri, P., Roengrit, T., Kanpetta, Y., Tong-un, T., Muchimapura, S., Wattanathorn, J. et al. (2013). Cashew apple juice supplementation enhanced fat utilization during high-intensity exercise in trained and untrained men. Journal of the International Society of Sports Nutrition. 10: 13.
Lower, S, T. & Agyente-Badu, C, K. (2009). Vitamin C contained in fruit. The Natural Food Hub.