The fiber factor: if you aren't filling up on enough fiber-rich foods, you may need an extra boost from supplements.(SUPPLEMENTS: SHOP SMART)

Fiber is essential for keeping things moving through our intestines and helping with a wide range of health issues. A diet rich in fiber does much more than just keep us, ahem, regular--it is also credited with helping prevent heart disease, type 2 diabetes, obesity and colon cancer. Studies have also shown that fiber intake is related to a reduced breast cancer risk.

What Exactly Is Fiber?

In basic terms, fiber is plant matter that we cannot digest, and it comes in two varieties, water soluble and insoluble. The soluble kind is found in legumes, fruits, vegetables and oats, whereas the insoluble type is found in wheat bran, whole-grain cereals, breads, and fruits with edible skin/seeds (such as strawberries and blueberries).

There are many natural sources of fiber, but unfortunately many people fail to reach the 20-35g a day recommended by the American Dietetic Association (most Americans only consume half this amount). To visualize 35g of fiber, think of the content in 14 shredded wheat biscuits or nine pears. Even if you are eating a rich and varied healthful diet, though, you may need to up your intake with a fiber supplement.

Soluble or Insoluble Fiber?

Your body needs both types of fiber to function efficiently. Soluble fiber aids digestion by slowing down the process so that nutrients are absorbed more gradually. This can help lower cholesterol levels. It also keeps you feeling full longer after meals--an advantage if you're trying to lose weight.

Conversely, the body cannot fully digest insoluble fiber; thus it bulks up the stool and acts as a natural laxative.