By David H. Rahm, M.D.
Q: I try to eat whole grain bread and pasta but I wonder if I’m getting enough fiber in my diet. Should I take a fiber supplement?
Ideally you want to get your daily fiber requirement from the foods you eat. Unfortunately, many popular foods from pizza to pasta and subs to snacks are not good sources of fiber. Taking a fiber supplement is a good way to fill in the gaps but increasing your intake of fiber-rich foods is preferable.
How Much Fiber Should I Have Daily?
We hear so much about the benefits of fiber. But, how much do we really need? According to the National Academies of Sciences’ Institute of Medicine, the recommended daily intake for total fiber in adults 50 years and younger is 38 grams for men and 25 grams for women. In adults over 50, it is 30 grams for men and 21 grams for women.
How Much Fiber are We Getting?
Despite efforts over the past decade to promote adequate fiber through fruit, vegetable, and whole-grain intake, fiber consumption has remained about half the daily recommended amount. In fact, more than 90 percents of adults and children fall short of meeting their daily fiber recommendations. Taking a fiber supplement can help fill in the gaps in your diet.
Not sure how much fiber you’re getting on a daily basis? I recommend that you complete a food log for a week. Calorie Count, a free online program with a mobile app, makes it super easy to determine the amount of fiber along with other macro and micronutrients you’re consuming. Yvette La-Garde, VitaMedica’s director of education says, “I tracked my food intake for 7 days on Calorie Count. Even though I am very health-conscious and eat lots of fruits and vegetables, I was surprised to learn that my average fiber intake was just 20 grams per day.”
What are the Health Benefits of Fiber?
By adding bulk to stool, fiber ensures that you have a bowel movement on a regular basis. Preventing constipation, the most common digestive complaint, minimizes your risk of developing problems with hemorrhoids, fissures, itching and other common colorectal problems. Aside from promoting regularity, high-fiber intake is associated with a number of other health benefits:
Heart health. Fiber helps raise HDL or “good” cholesterol levels while reducing LDL or “bad” cholesterol levels.
Colon health. Fiber helps to remove wastes and toxins, cleansing the the colon by sweeping them up and removing them through elimination. Studies have shown that dietary fiber is protective against colorectal cancer. Fiber is often prescribed for those with IBS, a common gastrointestinal complaint, to decrease symptoms such as abdominal pain.
Weight management. Different types of fiber may have an effect on satiety and energy intake. By making you feel full, fiber can help with weight loss. Fiber also slows down the absorption of glucose which stabilizes blood sugar and energy levels.
What is Dietary Fiber?
Dietary fiber comes from plant sources (nuts, whole grains, legumes, fruits and vegetables) and is typically classified as either soluble or insoluble. Although most plants have a combination of both types, foods are often classified based on their predominance of soluble or insoluble fiber. Some foods, like flax seed, have a more natural balance of insoluble to soluble fiber.
Soluble fiber. This type of fiber is not digested but when mixed with water, forms a gel-like substance and swells. Soluble fiber – sometimes referred to as “prebiotic” fiber – can be fermented by the bacteria in the large intestine.
Soluble fiber plays a role in intestinal health and may be helpful for relieving diarrhea, constipation and abdominal discomfort. Soluble fiber is also noted for its benefit in lowering total cholesterol and LDL or “bad” cholesterol, providing cardiovascular benefit. Soluble fiber moderates blood glucose levels, which is beneficial for people with diabetes.
Insoluble fiber. Also known as “roughage”, this type of fiber does not dissolve in water, passes through our intestines largely intact. Insoluble fiber moves bulk through the intestines and is responsible for keeping us “regular”. Insoluble fiber is associated with intestinal health including a reduction in the risk and occurrence of colorectal cancer, hemorrhoids and constipation.
Resistant starch. Research has identified yet a third type of fiber called resistant starch. As the name implies, resistant starch (a carbohydrate) “resists” digestion in the small intestine. Instead, this starch passes through to the large intestine where, through fermentation, the starch acts like dietary fiber. Because this type of starch is not digested it is referred to as a non-glycemic carbohydrate (does not affect blood sugar levels).
Consuming foods that contain natural resistant starch positively affects weight management by increasing satiety (sense of fullness) and altering the secretion of hormones related to food digestion. Resistant starch may help to burn fat and may lead to lower fat accumulation.
Good Sources of Fiber
Food sources of soluble fiber include oat/oat bran, dried beans and peas, nuts, barley, fruits (such as oranges and apples), vegetables (such as carrots) and psyllium seed husk. Inulin and fructo-oligosaccharides (FOS) are two types of soluble fiber that are sometimes combined with probiotics to enhance the development of beneficial bacteria within the gastrointestinal tract.
Sources of insoluble fiber include whole grain foods, wheat and corn bran, nuts and seeds, vegetables and the skins of some fruits such as berries.
Resistant starch is naturally present in foods such as whole grains and legumes. For example, a half cup of cooked navy beans provides 9.8 grams of resistant starch.
How to Get More Fiber in Your Diet?
One of the best ways to get more fiber is to eat whole foods like fruits, vegetables, beans, whole grains, nuts and seeds which are naturally rich in fiber. To determine the amount of fiber in a wide range of foods, refer to the Fiber Content of Foods.
Here’s some suggestions on how you can increase your fiber intake from whole foods:
- Add fresh fruit to yogurt or smoothies.
- Add beans to soups, stews and salads.
- Replace white rice with brown rice or with an ancient grain like quinoa.
- Switch out starchy carbs with high fiber vegetables like spinach, carrots and broccoli.
- Snack on a piece of fresh fruit (pear or apple) or dried fruit (figs, raisins, apricots).
- Add nuts and seeds especially almonds & sunflower seeds to salads.
- Snack on raw veggies with hummus.
- Eat a bowl of berries (raspberries, blackberries, blueberries) for dessert.
Ms. La-Garde offers this advice, “I look at every eating occasion as an opportunity to add a fruit or vegetable. If I make an omelet, I add bell pepper and mushrooms then serve tomato slices on the side. I buy plain, non-fat Greek yogurt and add fresh fruit. Then, I top with nuts and ground flax seed. My salads don’t contain just lettuce but tomato, bell pepper, cucumber, carrot and chick peas. I make lots of soups with beans and legumes. I also try to serve two or three vegetables at dinnertime. For dessert, I’ll often serve fruit and berries.”
What about Whole Grains?
According to the 2010 Dietary Guidelines, at least half of all grains eaten each day should be whole (that is, intact, ground, cracked or flaked). A whole grain is defined by the kernel, or seed, of the grain plant having all three key components intact: the bran, the germ, and the endosperm. Key nutrients and fiber are found in the bran and the germ of grains.
While whole grains are a good source of fiber, you need to pay attention to labels. Many products can be deceiving in the way they are marketed leading you to believe they are whole grain. True whole grain products will be labeled as “whole grain” or “100% whole wheat”.
Look for the Whole Grain Stamp on packaging. The 100% Stamp guarantees all the product’s grain ingredients are whole grains. To qualify for the 100% Stamp a minimum of 16g of whole grains per serving is required. The Basic Stamp signifies a product containing at least 8g of whole grains per serving, but may also contain some refined grains.
Read the ingredient statement carefully. Whole grains are typically listed near the top and specific phrases such as “whole grain” or “whole” will describe the type of grain contained in the product.
What are Ancient Grains?
Most of us limit our grains to barley, corn, oats, rice and wheat, but you can add variety to your diet by including some ancient grains. Ancient grains including quinoa, amaranth, spelt, kamut, wheatberry, teff, chia seeds and farro are showing up in everything from breads to pasta. They offer tastes and textures that differ from conventional grains.
While technically not all grains (some are grasses or seeds), ancient grains, can be higher in protein, Omega-3s and phytonutrients than other grains. They are also a good source of fiber. Some, not all ancient grains, are safe for people with wheat allergies and gluten-intolerance.
What Types of Fiber Supplements are Available?
If you’ve been down the digestive aisle of your local drugstore or Whole Foods, you’ll notice a wide range of fiber supplements.
Products are available in powder, capsule, wafer and chewable tablets. Powders provide a higher level of fiber per serving (about 3-6 grams) than capsules (about 1-2 grams) with 3 to 5 capsules.
Some brands like Metamucil formulate their product with one ingredient while others use a combination of fibers. The product that is right for you will depend on your needs and taste preferences.
Here’s a list of key ingredients in fiber supplements, their uses and benefits:
Psyllium. The active ingredient in Metamucil and Konsyl, psyllium is a soluble fiber from the seeds or husks of the plantago ovata plant. India is a large supplier of psyllium where the plant is cultivated with the heavy use of insecticides and pesticides. When taking this supplement, look for brands that offer organically grown psyllium. NOW Foods offers a 100% organic psyllium supplement. Because psyllium is digested, a serving contains about 50 calories and this type of fiber may cause gas.
Methylcellulose. The active ingredient in Citrucel, cellulose is an insoluble fiber derived from the cell wall of plants. Considered “nature’s laxative”, methylcellulose is less likely to cause intestinal gas as the fiber is not fermented in the gut.
Polycarbophil. The active ingredient in FiberCon, polycarbophil is an insoluble fiber created from plants. It is less likely to cause bloating than psyllium and is used to treat constipation, IBS and diverticulosis.
Vegetable & fruit fibers. Pectins are naturally found in fruits, berries and seeds including apples, carrots, cabbage, bananas and citrus fruits. Usually found in more “natural” brands, vegetable and fruit fibers are derived from a variety of sources including apple pectin, acacia fiber, and carob powder. Most pectins a soluble source of fiber, which slows the passage of food in the digestive tract and helps lower blood cholesterol. Futurebiotics offers an apple pectin supplement that provides 500 mg of apple pectin per serving.
Flax seed. Ground flax seed is a good source of soluble and insoluble fiber. Flax seeds also contain lignans, a phytonutrient associated with breast and prostate health. NOW Foods offers Fiber-3, a supplement that contains organic flax seed meal, organic acacia, and organic inulin.
Guar gum. Guar gum is obtained from the ground endosperm of the guar bean plant. SunFiber® is a branded ingredient that combines guar gum, apple pectin, prune powder, larch arabinogalactan, and green tea phytosome to assist weight control by providing a satiety effect.
Inulin & FOS. A type of soluble fiber extracted from several fruits and vegetables including chicory root, Jerusalem artichoke and onions. Considered a prebiotic, inulin is a food source for the beneficial bacteria that reside in the GI tract. VitaMedica’s Probiotic-8 is formulated with inulin.
Beta-glucan. A soluble fiber naturally found in the cell walls of plants, algae, bacteria, fungi and yeasts. Beta-glucan is commonly used for its cholesterol lowering effects.
Glucomannan. A soluble type of fiber derived from Konjac Root which can be used for constipation, maintaining cholesterol levels and weight management. LeanBiotics’ Prebiotic is formulated with glucomannan.
Dextrins. Short-chain carbohydrates that are made from starches and are soluble. Wheat dextrin is extracted from wheat starch and used to add fiber to processed foods. Fibersol2® is a branded ingredient that is made from corn fiber that helps relieve constipation. Fibersol2 has been demonstrated to delay post-meal hunger and increase satiety hormones.
How to Take Fiber Supplements
If you’re going to take a fiber supplement, start slowly. Too much fiber, too quickly can lead to bloating, gas, cramping. Gradually increase the amount of fiber that you’re taking each day to allow the beneficial bacteria in your GI tract to adjust to the change. Also, drink plenty of water when taking a fiber supplement to prevent constipation or a bowel obstruction.
Some medications interact with fiber supplements so you should discuss with your doctor before taking a fiber supplement. For example, fiber can decrease the absorption of certain medications such as aspirin and warfarin (Coumadin). In general, take medications at least one hour before or two hours after taking a fiber supplement.
Excess fiber can bind to the minerals iron, zinc, calcium and magnesium and decrease their absorption.
David H. Rahm, M.D. is the founder and medical director of The Wellness Center, a medical clinic located in Long Beach, CA. Dr. Rahm is also president and medical director of VitaMedica. Dr. Rahm is one of a select group of conventional medical doctors who have education and expertise in functional medicine and nutritional science. Over the past 20 years, Dr. Rahm has published articles in the plastic surgery literature and educated physicians about the importance of good peri-operative nutrition.