Oatmeal, oat bran, barley, lentils and beans are high in soluble fiber. Strawberries, blueberries, apples, oranges and pears are fruits with high amounts of soluble fiber, while cucumbers, asparagus, Brussels sprouts, celery and carrots are good vegetable choices.
Black beans, kidney beans and navy beans are especially high in soluble fiber, while legumes such as peanuts and peas are high in both soluble and insoluble fibers. Flaxseeds have the highest amount of soluble fiber found in seeds, with 1.1 grams of soluble fiber in 1 tablespoon. Psyllium is a popular soluble fiber supplement. Apricots, grapefruit and mangoes are fruits that contain more soluble fiber than insoluble. Turnips and sweet potatoes are high in soluble fiber.
Soluble fibers attract and absorb water to form a gel that acts to slow digestion, giving a feeling of fullness that is helpful in weight control. This slowing down of the stomach emptying process may have a beneficial effect on blood sugar levels, according to WebMD, helping to control diabetes by improving insulin sensitivity. Soluble fibers also lower LDL cholesterol levels in the blood by blocking the absorption of dietary cholesterol.
Insoluble fibers do not dissolve in water. They add bulk to the diet and help to prevent constipation by passing through the digestive tract quickly and intact. Good sources of insoluble fiber found primarily in whole grains and vegetables include corn, bulgur, brown rice, broccoli and dark, leafy greens.