Soluble fiber may help lower lipoprotein protein, LDL, or "bad" cholesterol and blood sugar, the Mayo Clinic Health Letter reports.

Fiber comes in two forms -- soluble fiber, which dissolves in water to form a gel-like material and comes from beans, some fruits and even coffee, and insoluble fiber, which doesn't dissolve in water and passes through the digestive system largely unchanged. Sources of insoluble fiber are cereals, wheat bran, and the stalks and peels of fruits and vegetables, the American Dietetic Association says.

The American Dietetic Association recommends the daily allowance of dietary fiber for men is 30 to 38 grams per day and for women, 21 to 25 grams.

A study, published in the Journal of Agricultural and Food Chemistry, found one cup of coffee per day contains up to 1.8 grams of soluble fiber.

The Mayo Clinic Health Letter says other good sources of soluble fiber include beans, fruits, berries, vegetables and oatmeal.