Melon Any kind of melon is great at cleansing the colon, and at a pH level of 8.5, they are super alkaline. Watermelon is especially good for you due to its high fiber and 92% water content. Buckwheat Looking for a replacement to wheat? Buckwheat is a great place to start! It will kick start your day by improving energy and can even help prevent cardiovascular disease. Olive Oil This tasty oil is rich in vitamin E and monounsaturated fatty acids. Flax Seeds Not only are they alkaline, but flax seeds are also high in fiber and vitamin E.