Walnuts have warm and sweet properties, in which can tonify kidney yang and nourish lungs. It is said in Materia Medica that "walnuts can benefit qi and nourish blood, moisten dryness and resolve phlegm, tonify Ming Men (kidney yang), clear sanjiao, warm lung and moisten the intestines to treat cough and wheezing due to deficiency and affected by cold, heaviness and pain in the waist". It is used for people with kidney yang deficiency with presentations such as cold sensation in the lower back with pain and relieved with warmth, frequent urination, tinnitus and sexual dysfunction.
As with most nuts and its healthy fat content, Chinese Medicine believes that fats act as a lubricant and it has the function of "moistening the intestines". This means that it can help to soften hard stools for people suffering from constipation. Walnuts are also known to promote healthy gut by increasing good microbiomes that produce a type of fat called butyrate which can nourish the gut. These gut microbiomes can also help the body to reduce the bad LDL cholesterol.
Walnuts are rich in omega-3, anti-inflammatory phytochemicals and antioxidents, all benefits brain function and maintaining brain health. Chinese Medicine believes that "the kidney connects to the brain; when the kidney essence is filled, the sea of marrow (brain) is filled". By tonifying the kidney will benefit the brain to improve cognition and boost memory.