The Nutritional Composition and Health Benefits of Lincang Walnuts

*Corresponding author: Carolyn E. Lister*, Yi Xiao, Jianrong Yang, Janine M. Cooney, Dwayne J. Jensen, Yongfeng Tang, Fengrui Xie, Lijing Chen, Xuejiang Tie and Hongxing Tian

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Although there is considerable information on the nutritional composition of the common walnut, information on the iron walnut is scarce.


To analyze the nutritional composition of Lincang walnuts (which belong to the species Juglans sigillata L., also known as the iron walnut) and if they confer any advantages over Xinjiang or Californian walnuts (both Juglans regia L. or common walnut).


Nutrients of particular nutritional significance in Lincang walnuts (both regular and old tree) were protein (5.9 and 5.6 g/30 g serve), dietary fiber (6.5 and 6.7 g/30 g serve), vitamin B6 (0.87 and 0.93 mg/30 g serve), copper (1.65 and 1.63 mg/30 g serve), magnesium (158 and 142 g/30 g serve), manganese (7.33 and 8.41 mg/30 g serve) and phosphorus (437 and 427 g/30 g serve). Despite a high fat content, the fatty acids profile was predominantly polyunsaturated and monounsaturated types. The Lincang walnuts were similar in macronutrient composition to the Xinjiang and Californian-sourced samples, but the Lincang ones were higher in some of the B vitamins (niacin, thiamin, and vitamin B6) and minerals (manganese and to a lesser extent copper, iron, phosphorus, and potassium). The serotonin concentration in Lincang walnuts (7.6 and 7.2 mg/30 g serve) was over double that found in Californian walnuts (2.9 mg/30 g serve) and higher than Xinjiang walnuts (5.5 mg/30 g serve).


The nutrients present in Lincang walnuts confer a range of well-established health benefits. One area of particular interest is the role that walnuts may play in brain function owing to the combination of nutrients and phytochemicals present. In addition to direct consumption of walnuts, there are many options for the development of functional food products, including walnuts as ingredients, to promote regular consumption of walnuts for improvement of health.


Walnuts; Juglans sigillata; Juglans regia; Nutrients; Brain health; Vitamin; Mineral; Fatty acid; Serotonin.