There are many causes of dark circles under the eyes, including heredity, tiredness and anaemia; however, one of the reasons for dark circles can be poor circulation. To address this cause and alleviate under-eye shadows, try to up your intake of vitamins K and C, which help to boost circulation and strengthen capillary walls. Dark, leafy greens such as spinach are good sources of these nutrients.What to eat: Spinach. From : Gulf news.