It is said that vitamin C, vitamin E, vitamin K are helpful for reducing dark circles under eyes. So, you can eat some food that are rich in vitamin C, vitamin E, vitamin K iron . And most of food are vegetables and fruit, such as:
You can take some orange and kiwi, berries green leafy vegetables, guavas, tomatoes, melons, papayas , since they are rich in Vitamin C
And food such as nuts, oils, vegetables, sunflower seeds, whole grains, spinach, oils, seeds, wheat oils, asparagus, avocado, beef, seafood, apples, carrots, celery are rich in Vitamin E
And take some food rich in Vitamin K such as spinach and celery, cheese, liver, asparagus, coffee, bacon, green tea and etc.
As for food rich in iron,they are chard, spinach, turmeric, thyme, shitake mushrooms, seeds, green beans, cereals, grains, meat, fish etc.
Those are the food that you can take for reducing dark circles, but it is not the only way you can do. You need to take a good rest, sleep enough hours for reducing it.