Friday, October 23, 2015

Dietary Fiber 101



Photo courtesy of Food explorer RD 


Fiber is a substance found in all plant-based foods. Most fiber is not digested or absorbed. It stays in the intestine where is helps the digestion of other foods. There are two kinds of fiber: soluble and insoluble. They both play an essential role in our health. Dietary fiber includes both soluble and insoluble fibers.

Soluble fiber is a substance that is made of carbohydrates and pulls in water to form a gel in the digestive tract, bulking up the stool. It helps to bring down cholesterol levels, prevent heart disease and stroke, and improve glucose tolerance in those who have diabetes. Common examples of soluble fiber are fruits, oats, barley, and legumes (peas and beans). Soluble fiber is also the type of fiber that is common in many over-the-counter laxatives. Pectin and the soft parts of fruits, dried beans are other examples of soluble fiber.

Insoluble fiber is a substance that comes from plant cell walls and does not dissolve in water. It can be found in peels of fruit, wheat, rye, and other grains (eg: wheat bran). Insoluble fiber acts as a laxative and helps move the passage of foods through the stomach, increasing stool bulk, consequently, helping reduce the risk for hemorrhoids and diverticulosis.

Dietary fiber promotes good “gut” health. Many studies show that dietary fiber relieves constipation by adding bulk to stool and moving it faster through the intestines. It can also relieve mild to moderate diarrhea, soaking up water in the digestive tract to make stool firmer and slower to pass. Include dietary fiber with your daily meals to care for your gastrointestinal tract.

There are other diseases that may be better controlled by increasing the amount of fiber in your diet. Soluble fiber such as psyllium, pectin, guar gum, flaxseed, and oat bran can help lower cholesterol. A high fiber diet may also help prevent type 2 diabetes, lower insulin, and blood sugar levels, and improve cholesterol and triglyceride levels in people with diabetes. You may also reduce your risk of developing Type 2 diabetes by with a high fiber diet. Eating more fruits, vegetables, or whole grains helps you better manage your diabetes and cholesterol levels.

Dietary fiber may help you control your weight. Eating soluble fiber may make you feel more satisfied so you eat less and lose weight. Another benefit of modifying your diet to include more fiber is that it can help curb weight gain in the waist area. Controlling your weight is a good way to manage your health and, overall, prevent chronic diseases.

Be aware that fiber may not be helpful for people with medical issues involving the intestines such as irritable bowel syndrome, diverticulosis, or bowel obstruction. You will need to talk to your doctor, dietitian, or health care provider if incorporating dietary fiber is appropriate for you.

So, how much is required per day?

The Institute of Medicine recommends approximately 20-35 grams of dietary fiber daily. That’s equivalent to eating 4-6 large (3 ¼” diameter or 182g) apple, raw, with skin a day! It’s no wonder the average adult in the US falls short of meeting the daily required dietary fiber. The average eaten is only 15 grams of dietary fiber a day.

Here is another way to show the daily dietary fiber recommendations for most healthy adults from the American Academy of Nutrition and Dietetics (AND):

Gender
Age
Recommended grams   fiber/day
Men
50 years and younger:
38 
Men
51 years and older
30 
Women
50 years and younger
25 
Women
51 years and older
21 

How can you meet the daily requirement for dietary fiber?

It involves planning! Plan to include dietary fiber sources as part of your 
every meal. Include a fruit and/or vegetable at each meal and snack. Eat more natural, whole foods like nuts, seeds, beans, lentils, fruits (with skin), and vegetables instead of eating processed foods. Remember that your health is your best investment. So, invest in foods that will keep you around stronger and longer!

Are you eating enough fiber? 
Take the Fruit/Vegetable/Fiber Screener to see if and by how much you need to improve.

The United States Department of Agriculture (USDA), Agricultural Research Service has a useful and comprehensive database to check how much dietary fiber is in a particular food. Log on to their website for the National NutrientDatabase for Standard Reference

What other foods have fiber? Check the Fiber Chart for other food sources of fiber. 

Below is a sample 1-day high fiber diet menu from Academy of Nutrition's Nutrition Care Manual for High-Fiber Nutrition Therapy. It will give you an idea of how to include fiber to your meals.

Breakfast
1/2 cup orange juice, with pulp
1/2 cup raisin bran
1 cup coffee
1 cup fat-free milk
(Approximately 250kcal, 11g protein, 3g dietary fiber)

Morning Snack
1 cup plain yogurt
2 cups water
(Approximately  130kcal, 13g protein, 0g dietary fiber)

Lunch
8 whole wheat crackers
1/2 cup kidney beans
1/2 cup soy crumble
1 apple (with skin)
2 cups water or sugar-free lemonade
1 1/2 cups chili
2 tablespoons shredded cheese
(Approximately 560kcal, 26g protein, 17g dietary fiber)

Dinner
1/2 cup fresh berries
2 ounces sliced chicken
1 cup brown rice
2 cups mixed fresh vegetables
1 cup hot tea
1 ounce tofu
(Approximately 345kcal, 17g protein, 14g dietary fiber)

Evening Snack
2 tablespoons almonds
1 cup hot chocolate
(Approximately 300kcal, 13g protein, 5g dietary fiber)
Total nutrient value: approximately 1600kcal, 80g protein, 39g dietary fiber)


Ready, set, go for more fiber!

Increase dietary fiber with caution. There are several forms of fiber, besides whole food forms. Fiber is available as a supplement in the form of a tablet, capsule, or powder. It may reduce or delay your body’s absorption of certain medications. Take fiber supplements under the supervision of your doctor or health care provider as it may interact with medications.  

Always drink 8 ounces of water with fiber supplements. Hydrating well throughout the day is important for avoiding constipation. Do not take fiber supplements if you have impacted stool. Talk to your doctor or health care provider first before doing so.

Although consuming fiber is good, there are side effects if done too quickly. To help minimize side effects, slowly and gradually increase dietary fiber until stools become softer and more frequent. Otherwise, it may cause gas or abdominal bloating.



Sources: 

Fiber
AND Nutrition care manual. High- fiber food list. How much do you need?
Patient information: High-fiber diet (Beyond the Basics)

The blog content and information provided by Food Explorer RD is provided for informational purposes only. It is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions.