By Bonnie Jenkins, Advanced Natural Wellness

I never thought I’d see the day when fiber was sexy. But, sure enough, recent ads on TV and in magazines are promoting fiber as a way to “beautify the inside.” Of course, food manufacturers know that people are on the lookout for fiber in foods, so they’re “helping” you by mixing isolated fibers into a variety of food products that don’t normally contain fiber. That’s why you are starting to see things like high-fiber yogurt, ice cream and drink mixes.

Consumers are led to believe these isolated fibers offer the same health benefits as the fiber that occurs naturally in food. Truth? Not on your life! Added fiber from inulin, polydextrose and maltodextrin may boost the amount of fiber that can be listed on nutritional labels but don’t be fooled—these isolated fibers don’t behave the same way as the natural fiber found in whole grains, legumes, fruits and vegetables. That means you won’t get the same health benefits from them.

The government’s Dietary Guidelines suggest that you get 14 grams of fiber per 1,000 calories—about 28 grams a day on average. But most of us get about half that amount. Fiber has many documented health benefits, including helping to maintain a healthy weight, lowering cholesterol and glucose levels, and reducing the risk of certain cancers, especially colon cancer. There’s also some evidence that fiber helps remove the toxins circulating through your body. If you aren’t getting enough natural fiber, you’re missing out on these key benefits.

One type of natural dietary fiber is soluble fiber, which helps with weight loss. It also lowers cholesterol and blood sugar levels. Sources of soluble fiber are oatmeal, oat bran, barley, dried beans and legumes, and citrus fruits. Insoluble fiber—another type of natural fiber—speeds up the passage of material through the digestive tract, thus lowering the risk of colon cancer and other digestive tract disorders. Insoluble fiber can be found in wheat bran, whole grain cereals, and fruit and vegetable skins.

But when you read the nutrition facts on a granola bar and see that it has 12 grams of fiber, you can bet that it isn’t all natural fiber. Considering that most high-fiber foods naturally contain about two to 10 grams of fiber per serving, that’s a lot of fiber for one little energy bar. And you can be sure that a good portion of that fiber is from inulin, polydextrose or maltodextrin. These three isolated fibers are soluble but they aren’t viscous or gummy so they don’t lower cholesterol or blood sugar. And polydextrose,in amounts larger than 15 grams, may cause a laxative effect for some sensitive folks.

Of course, it would be way too easy if isolated fiber was simply listed as inulin, polydextrose or maltodextrin. Isolated fibers added to foods can also appear as “wheat fiber” or “oat hull fiber” on the ingredient list. These ingredients, while natural, are insoluble fibers that can provide digestive tract benefits without the heart-health benefits. “Oat fiber” on the ingredient list can be either insoluble or soluble fiber. And, inulin—which comes from chicory root—may nourish the good bacteria in your digestive tract, but there’s not much evidence that it offers the same disease-protective benefits of naturally-occurring fibers found in foods. The same goes for the other isolated fibers, polydextrose and maltodextrin. If you see the fiber, “bran” (from wheat or oat), you’re getting the nutritious, fiber-rich outer layer of the grain’s kernel. Unfortunately, when you see grams of fiber listed on the nutrition facts panel, it’s hard to tell how much is from naturally-occurring fiber versus added isolated fibers.

The bulk of the evidence on fiber’s benefits comes from real, fiber-rich plant foods. These foods may even offer a synergistic health benefit from a host of vitamins, minerals, phytonutrients and fibers found naturally in the food. It’s also important to get a variety of fiber-rich foods, so you get the benefits of soluble and insoluble fibers. One way to get “real” fiber, is to opt for whole plant foods instead of processed foods. Try old-fashioned oats with berries and walnuts instead of that processed high-fiber energy bar.

References:

Prosky L. When is dietary fiber considered a functional food? Biofactors. 2000;12:289-297.

Schwab U, et al. Impact of sugar beet pectin and polydextrose on fasting and postprandial glycemia and fasting concentrations of serum total and lipoprotein lipids in middle-aged subjects with abnormal glucose metabolism. European Journal of Clinical Nutrition. 2006;60:1073-1080.