There are a few main points to consider when deciding which fiber supplement to try, and this page gives an overview of the things you might look for in your supplement. Bear in mind that all fiber supplements should be taken in small doses at first, with lots of water, while you work your way up to the recommended dose. Also, if the first supplement you try gives you bad gas or other IBS symptoms then it is always worth trying another type of fiber. The recommended intake of fiber for an average person is 25 to 35 grams per day (source: the American Dietetic Association).
Type of fiber
The leading brands use a range of different fibers in their products. The most common type of fiber is psyllium, a soluble plant fiber found in Metamucil and Konsyl. This is a popular fiber for helping to relieve constipation, and it may also help general IBS symptoms. It is worth noting though that some people do experience problems with psyllium fiber and may find another type less harsh on their stomachs.
Other brands use methylcellulose (a plant fiber found in Citrucel), calcium polycarbophil (a synthetic fiber found in Fibercon and Equalactin), and guar gum (the plant fiber in Benefiber, although some Benefiber products now use wheat dextrin as well). There's no easy way to say which fiber will suit you the best, and it may be a trial and error process to find one that works for you. A final type of fiber, acacia fiber, is also available.
All of these fiber supplements contain soluble fiber, which means that the fiber absorbs water and forms a gel when mixed with liquid, which is why it can be so useful in helping food move smoothly through the gut. Soluble fiber is now generally accepted to be more helpful in easing IBS symptoms than insoluble fiber, which is why the old treatment of giving IBS patients lots of bran has now fallen out of fashion (bran contains insoluble fiber). However, it is still important to eat insoluble fiber in your diet as it is important for good health.
Grams of fiber per serving
Because they are made from different ingredients, fiber supplements also contain differing amounts of actual fiber per dose. Here is a rough guide to the fiber quantities in each product:
Konsyl - 6g
Acacia fiber - 4.5g
Metamucil - 3.4g
Benefiber - 3g
Citrucel - 2g
Fibercon - 1g
Flavorings and other factors
Many of the brands have added flavoring, often orange for some reason, to make the supplements more palatable and easy to drink. Alternatively, some of the brands such as Citrucel offer a clear mix version, where no flavoring is added and the powder can be stirred into any drink without changing the flavor.
It may be worth steering clear of any 'sugar-free' versions of fiber. This is because the sweeteners which are used instead of sugar may irritate a sensitive IBS bowel. Sweetener names to look out for include sorbitol, aspartame and sucralose, among others. Be vigilant for other ingredients as well - although most of the supplements only contain fiber plus added flavors or sweeteners, you may come across one or two which also include a chemical laxative, which could be harmful if taken for a long period of time.
Some IBS sufferers find that their symptoms improve if they avoid gluten. Here are the gluten-related details for each of the main fiber supplements:
Benefiber - gluten-free
Citrucel - gluten-free
Fibercon - gluten-free
Konsyl - gluten-free
Metamucil powder and capsules - gluten-free
Metamucil wafers - contain gluten
Acacia fiber - gluten-free
Powder, tablet or wafer
fiber supplements are frequently sold in a powder form which comes in a tub and is mixed into water or soft food. However, there are now several other ways to take fiber. Metamucil produce a wafer form of their product, Benefiber produce chewable orange tablets, and Fibercon comes in capsule form.
In fact, most of the leading brands now produce their fiber in either tablet or wafer form, so if you are traveling or staying with friends you can easily take some fiber with you without carrying around a big tub of powder.
Finally, of course, most of us need to think about the price, especially if we are going to be using the supplement over a long period of time. Fortunately, fiber supplements are generally cheap because they are relatively simple products made from inexpensive ingredients.
For example, a standard 48oz tub of Metamucill will generally cost around $12-13. Prices do vary between the different supplements though, so if money is a real worry for you then you could consider choosing a cheaper supplement, especially if you are choosing between two supplements which use the same type of fiber (such as the psyllium fiber in Konsyl and Metamucil).
OK, now I'm confused - can you recommend one to try?
If you've never tried a fiber supplement before I would recommend trying acacia fiber. I would recommend this one because it is not a psyllium product (psyllium can agitate some IBS stomachs), it contains a high level of fiber per dose (4.5 grams), and it is made by Heather Van Vorous, who is an expert on IBS and has written some of the bestselling books on IBS, including Eating for IBS and The First Year - IBS.
acacia fiber is also designed to have prebiotic properties, meaning that it helps to nourish the friendly bacteria in the gut which can help digestion.