Fiber Showdown: Soluble vs. Insoluble Fiber

Dietary fiber is classified based on its solubility. Soluble fiber can dissolve in water whereas insoluble fiber can't.

Soluble Fiber

Soluble fiber can dissolve in water, which slows down digestion. This is the type of fiber that is thought to lower blood cholesterol levels, which in turn reduces heart disease risk. It also helps regulate blood sugar levels.

In your diet, you get soluble fiber from:

• Oat bran
• Barley
• Psyllium
• Nuts
• Seeds
• Beans
• Lentils & peas
• Some fruits & vegetables

Insoluble Fiber

Insoluble fiber doesn't slow down digestion like soluble fiber does, rather it is linked to "laxation". Insoluble fiber adds bulk to your stools and actually makes food pass through your digestive system more quickly than it would without the fiber. This is the type of fiber that helps promote good bowel regularity and reduces constipation.

Insoluble fiber in the diet comes from:

• Wheat bran
• Certain fruits & vegetables
• Whole grains

Recommendations

Dietitians recommend that you don't fret about eating soluble vs. insoluble fibers. Instead, your focus should be on increasing and achieving recommended levels of total dietary fiber. Most high fiber foods will naturally have a combination of both soluble and insoluble fibers. For example, in fruit, the soluble fiber is found in the flesh and the insoluble comes from the peels. Eating the whole piece of fruit maximizes your fiber intake, and health benefits from fiber come from a combination of both types.

Here's an example of a high fiber food rocking equal amounts of soluble and insoluble fiber. This label is from Quaker Oats. You can see that per serving, you get 4 grams of fiber: 2 soluble and 2 insoluble.

List of Whole Grains and Not Whole Grains

Since whole grains are high in fiber, increasing fiber intake usually means you have to increase your intake of whole grains. But what exactly is a whole grain? As covered in an earlier post, a whole grain consists of three parts:

1. Bran
2. Endosperm
3. Germ

Based on the FDA's Whole Grain Label Statements Draft Guidance, here is a list of whole grains and those not considered whole grains:

Whole Grains

Cereal Grains that can be Whole Grains:

• Amaranth
• Barley
• Buckwheat
• Bulgur
• Corn - includes popcorn
  
• Millet
• Quinoa
• Rice
• Rye
• Oats
• Sorghum
• Teff
• Triticale
• Wheat
• Wild Rice
  

Oats are Whole Grains

• Oatmeal
• Rolled Oats
• Quick Oats

Not Whole Grains

Legumes are Not Whole Grains (...but they are still high in fiber)

• Soybean
• Chickpea
• Oilseeds (i.e. sunflower seeds) and roots (i.e. arrowroot) derived from legumes

Tweeners

Barley

• Pearled barley is not a whole grain since the processing involves removing some of the bran
• Dehulled barley (not pearled) is a whole grain

Durum Wheat - High protein, yellow flour used in pasta

• Durum wheat used in semolina and flour is not whole grain
• 100% durum wheat or whole durum wheat is a whole grain
  

Fiber Recommendations for Kids

Adequate Intake level recommendations for fiber are gender and age specific. In this blog we've looked at fiber recommendations for adults - but what about kids? The DRI Committee - (Dietary Reference Intake Committee) has set forth loose recommendations for children and fiber - and they say:

Babies 0-6 months
There is no fiber level set for the first six months of life. At this stage, a baby's diet consists solely of breastmilk or formula, neither of which provide any fiber.

Babies 7-12 months
For the second half of the first year of life - although introduction of solid and fiber-containing foods does occur - there is not enough data to set a recommended level for fiber.

Kids 1-3 years
Most healthcare professionals recommend introducing a variety of fruits and vegetables and cereals at this age. Kids aged 1-3 should aim to have 19 grams of fiber per day.

Age 9-13 years
Starting in this age bracket, fiber recommendations differ by gender. Nine-13 year old girls need 26 grams of fiber per day and boys should be eating 31 grams per day.

Kids 4-8 years
For 4-8 year olds, the fiber recommendation is 25 grams per day.

Age 9-13 years
Starting in this age bracket, fiber recommendations differ by gender. Nine-13 year old girls need 26 grams of fiber per day and boys should be eating 31 grams per day.

Age 14-18 years
In adolescence, 14-18 year old girls' fiber needs are 26 grams per day and males increase to 38 grams per day.

Age + 5-10 grams
Researchers in New York determined that a safe range of dietary fiber intake for kids is equal to a child's age plus 5-10 grams of fiber per day*.

*Source: Williams CL, Bollella M, Wynder EL. A new recommendation for dietary fiber intake in childhood. Pediatrics. 1995;96(5 Pt 2):985-988.

Fiber, "What more do you want from me?"

Despite the well established litany of health benefits associated with high fiber intake, researchers just keep it coming! A study published in the July 2009 issue of the American Diabetes Association's Diabetes Care journal showed that people with lower dietary fiber intake had increased risk of diabetes. Likewise, eating more fiber is associated with reduced diabetes risk and reduced inflammation. With 24 million Americans already suffering from diabetes - now seems like a pretty good time to start bumping up your fiber intake.

Stir Crazy: Pop to It

Air popped popcorn is an insane fiber find. Five cups of air-popped popcorn gets you 6 grams of fiber for only 150 calories - an excellent, unadulterated, high-fiber snacking option. But many air poppers just don't cut it. If your popcorn tastes stale, it's probably not the kernels - but rather your popper - that is to blame. Enter West Bend's Stir Crazy® Corn Popper. This magical appliance utilizes a rotating metal rod to keep kernels from attaching to its non-stick surface. The plastic cover can be conveniently inverted to serve as your bowl. Best of all, it churns out glorious, puffy kernels with no need for added oil, and no chewy, stale output either. It's a bit cumbersome when it comes to storage, but you'll get over it once you taste Stir Crazy's consistently good results. The Stir Crazy Corn Popper is available at Target for $25 or on Amazon for $34.