Leafy greens fade more quickly so you need to use within a couple of days.

Source: https://www.dailystar.co.uk/real-life/youre-storing-christmas-leftovers-wrong-31565093

Leafy greens, such as Kale, spinach, and collard greens, are rich in vitamins like K, C, and E, which help to regenerate the brain cells and improve cognitive function.

Source: https://doctor.ndtv.com/living-healthy/brain-eating-these-brain-foods-could-boost-your-brain-health-3925574

Leafy greens such as kale, spinach, broccoli and cauliflower are also a rich source so including a variety of these in the diet is important.

Source: https://www.huffingtonpost.co.uk/entry/diet-and-fertility-link-explained-by-dietitian_uk_6450ba82e4b03c1b88cf0427