Is fiber good for health?
If just a fraction of the studies reported are correct, the answer is a resounding yes. Dietary fiber has been shown to reduce the risk of cancer, heart disease, mitigate the blood sugar fluctuations of diabetes, and allow kidney failure patients to eat more protein.
However, the primary reason most people make an effort to get fiber is much simpler and easier to understand to put it delicately, it keeps your digestive tract operating comfortably, by preventing constipation, hemorrhoids, and diverticular disease.
How does fiber affect the digestive tract?
When everything is running well, adding fiber to your diet helps ensure that it will continue to do so, by giving your intestinal tract movement (peristalsis) something to work on. By holding a lot of water relative to the amount of dry stuff (even the insoluble does this to some extent), it produces bulk. These all help with the mechanical aspects.
Soluble fermentable fiber does even more. It feeds your intestinal microflora. It is their by-products that make up the bulk of fecal material.
Help, I’m taking lots of psyllium but I still have a problem with constipation. What should I do?
Unfortunately, although fiber supplements are often called “bulk-forming laxatives,” they are laxatives only in the broadest use of the term. While they help prevent problems by giving your body something to work on, they not only don’t cure constipation once it has occurred, they can sometimes make it worse.
First you have to solve the problem (consult your doctor or pharmacist for a real laxative or increase your water and Vitamin C), and then use fiber to prevent reoccurrence.
Furthermore, although psyllium is readily available and mostly soluble fiber, it is not fermentable. In other words, it doesn’t do much for your microflora. You probably need to add some fermentable fiber to prevent further problems.
How does fiber provide other health benefits?
Scientists are still identifying benefits and finding explanations for the observed effects, so some of the mechanisms are still under investigation.
However, it is known that fiber binds and removes a number of things found in the digestive tract. That list includes bile salts which, while not undesirable themselves, require the body to use up more cholesterol to replace them, thereby improving blood lipids.
Fiber also binds or otherwise interferes with absorption of carbohydrates and fat — to some extent, in some people, under some circumstances.
Unfortunately, this potential benefit for dieters has not in a proven consistent manner, despite the advertising of some products. There is even evidence that extremely large amounts of at least one type of fiber can bind enough protein or protein by-products to allow kidney failure patients to eat a more normal diet.
Is fiber for everyone?
No, there are certain conditions, like gastroparesis, where consuming a significant amount of fiber can aggravate the condition.
How much fiber should we eat?
Nutrition recommendations are for 20-35 grams total of all types of dietary fiber per day. There appears to be no upper limit, as long as you don’t get too much from grain. There have been studies where subjects with serious medical problems consumed 50 grams a day of supplemental fiber and were able to adjust in just a week or two.
What are the best sources of dietary fiber?
The best food sources are fruits, vegetables, beans, seeds, and limited amounts of whole grains or their brans (see below). Most members of the plant kingdom provide us with at least a small amount of fiber, while animals, provide us with none. (Don’t let the use of the word “fiber” with respect to animals fool you it does not mean dietary fiber.)
Since lowcarb dieters cannot eat enough of many of the best sources of fiber to get even the minimum recommended amount, we have a special FAQ on fiber for lowcarbers.
What’s wrong with getting a lot of fiber from grain?
The high-fiber portion of grain is bran, the seeds’ outer covering. Brans contain phytates, chemicals which bind minerals and make them unavailable to the body. Overdoing this particular fiber source can lead to calcium and other mineral deficiencies.
How much of each type of fiber is recommended?
Unfortunately, there aren’t any lists, sources, or databases that list soluble versus insoluble fiber in foods. In the absence of that information, there is no point in recommending specific amounts by type. In addition, all fiber is considered beneficial to some degree, and few people consume the minimum of the most readily-available type.
However, given the numerous health benefits attributed to soluble fermentable fiber, and the difficulty in getting it from most diets, it makes to sense to focus attention in this direction.
What’s the best way to supplement fiber?
Try to take it as a bulk supplement. Capsules and tablets are an extremely expensive way to supplement, because so many are required to make a dent in your daily requirement.
Most contain approximately 500 mg in other words, just half a gram because most people have difficulty swallowing larger doses. In addition, since few people enjoy swallowing a lot of capsules and tablets, most end up getting only a small fraction of the recommended amount.
One alternative is that there are now a number of manufacturers, Expert Foods included, who make foods containing fiber. You can supplement your fiber while enjoying special snacks and desserts.
This is as expensive as taking capsule or tablet supplements, but the benefits of the foods, and the ease of getting useful amounts of fiber, may make this approach worthwhile.
Also, don’t fall for advertising hype about individual types of fiber. It’s not so much that the information is wrong but that the benefits claimed are not unique to any single product. Although producers who have cornered the supply of a particular type of fiber would like you to believe that theirs is best, all types of fiber within a class seem to have similar benefits.
Even if an expensive type is somewhat better in some aspect, most of us would be better off consuming a larger quantity of cheaper fiber, since so many fiber benefits are proportional to the amount consumed.
Remember to increase fiber intake gradually to give your intestinal flora time to adjust to their new food supply.