Walnuts are a rich source of the hormone melatonin, which is known to play a large role in sleep regulation. Combining the hormonal benefit of melatonin with the satiating benefits of their healthy fats, fibre, and plant-based proteins that this nut offers makes this nut an excellent choice for a bedtime snack.
An easy way to include walnut into a child's diet, especially if they are not developmentally ready to enjoy this whole nut, is to include walnut butter on snacks and sandwiches.