RECENT STUDIES AND ADVICE
A 2016 study suggests young men should eat a handful of walnuts each day to help their mood and overall health. And in a 2015 study suggests they may improve memory.
SOME ADVICE OF THE SCHOLARS
As-Suyuti in "Medicine of the Prophet" records that walnuts are difficult to digest and bad for the stomach, that fresh ones are best and walnuts mixed with honey is good for sore throats. He also said that figs and dates are good for the digestive system.
Al-Jawziyya in "Medicine of the Prophet" advised not to eat walnuts at night. The advice is also to eat walnuts when eating cheese.