Dietary fiber is one of the main components of a healthy human diet. Nutritionists have divided dietary fiber into two general types - the water soluble fiber and the water insoluble fiber. Dietary fibers of which are soluble have an ability to lower the cholesterol level in the body. At the same time, and for reasons that are still a mystery, human diets that contain a higher proportion of the insoluble type of dietary fiber tend to give better protection against the risk of heart disease and related cardiac problems.
In patients affected by lifestyle diseases such as diabetes, the soluble type of dietary fibers can also help lower elevated blood sugar levels, especially if insulin resistance is a serious problem. At the same time, some clinical researchers have discovered that increasing dietary fiber intake lowers the body's requirement for the insulin hormone - this is considered to be a good sign for diabetics, all of whom suffer from insulin resistance to varying degrees. This supposed effect has been questioned by a recent review of research results, which questions the real effectiveness of moderate dietary fiber consumption on insulin resistance. The fact is that, there is a lack of proof about a clear mechanism to show how insoluble fiber helps diabetics, similar to the lack of clear evidence connecting dietary fiber use with reduction in heart disease risk. At the same time, it is known that diets that are high in content of insoluble fiber, especially from whole grains, offer some protection from the late or adult onset diabetes type two.
The consumption of large amounts of insoluble dietary fibers helps in softening the stool, this results in the quick removal of the feces from the body. Dietary fiber is partially effective as a treatment for constipation, for this reason, the insoluble fibers serve as roughage. This shortening of the movement of stool through the tract or the lessening of the "transit time" of stool, is believed to protect a person from the risks of colon and other gastrointestinal cancers. This explanation may not necessarily be so simple, and the actual association between a high fiber diet and the risk of colon cancer seems to be much more complicated than first suggested. This realization has come from the careful analysis of results from different animal based studies, as an example, the consumption of wheat bran was stated to be significantly much more protective for test animals than the consumption of diets that were without wheat bran, but equally high in insoluble fibers from different foods. In addition, dietary fiber could possibly possess other forms of anticancer effects that are not connected to the "transit time" of stool or it may not even be connected to gastrointestinal tract at all but may be affecting some other unknown process. At the same time, certain clinical researchers suggest that the changes in bile acid metabolism occurring in the gastrointestinal tract may be a partial explanation of the special link that exists between the presence of wheat bran and colon cancer prevention. This protection conferred by the wheat bran is not an effect seen with all fiber rich foods; when clinicians studied the total fiber or even total grain fiber intake and colon cancer incidence with respect to other high fiber foods, it was found that, this protective effect was not conferred by most of these other foods.
Dietary fiber reduces appetite because it is very filling due to its bulk. The consumption of dietary fiber should contribute to weight loss, theoretically speaking, as it has bulk. Some researches have, however, found that increasing the dietary fiber intake will have no effect on body weight despite its ability to decreasing appetite over the long term.
The fiber like substance known as lignan, found in many plants possesses a mild anti-estrogenic activity in the body. This is the possible reason for the fact that high lignan levels detected in the urine is linked to a significant protection from breast cancer in humans - high levels of the substance in the urine is simply a reflection of high dietary intake of the substance.
- Fiber for weight control
- A diet high in fiber content may help a person slim down by "bulking up" the ingested food according to the results from clinical dietary research. During the course of a twenty four month study in which one thousand seventeen hundred overweight, obese, men and women of all ages were tested, it was found that tested subjects who has the highest dietary fiber intakes showed the greatest weight loss - the results from this recent study conclusively linked a high fiber diet with weight loss in humans. This relationship between a high fiber diet and a lowering of the body weight is also supported by the results from the Continuing Survey of Food Intakes by Individuals - CSFII - in a study conducted for two years, 1994 to 1996. Fiber has the ability to slow down the passage of food along the intestines due to its bulk nature; this is one of the principal reasons for its impact on body weight - it is the roughage that bulk up the digesting food in the gastrointestinal tract. The soluble dietary fibers form a gel like substance that dissolve in water and swell up, as a result they move slower along the intestines and bulk up the feces. This bulking of the digested food tends to increase the total time that food spends inside the intestines - an important factor in reducing the sense of hunger and food intake in general. A high fiber diet has also been connected to a decrease in the actual amount of calories absorbed from ingested food. The impact on calorie absorption of a high fiber diet was measured in one study, results showed that there was an increase in the number of calories excreted in the stool when the diet consisted of high fiber psyllium gum based crackers - the same effect was not seen when low fiber crackers were consumed in the study. Weight loss will always occur when the intake of calories is decreased or more are excreted than absorbed.
- Fiber for controlling diabetes
- Diets that are high in fiber may also be helpful in controlling elevated blood sugar. All persons will benefit from keeping blood sugars at stable levels; indeed, this is a goal that all individuals should strive for considering the high sugar content of most modern diets. The consumption of a diet high in dietary fiber is a good way to prevent the onset of type two diabetes, especially for individuals who may be susceptible to developing it. Similarly, diabetics may benefit from a diet high in fiber; such a diet could help keep the diabetes under control. Type two diabetes is a lifestyle disease, and its prevention should be a priority - the ideal time to control this disease is before it has a chance to develop fully. Result from recent clinical research suggests that the consumption of diets high in fiber may possibly help prevent this form of diabetes from developing. Healthy men and women who were overweight or obese but susceptible to diabetes were tested in a recent study, they were all given a dietary supplement that was high in soluble fibers, all the tested individuals showed reductions in the levels of blood sugar and insulin production as a result of the supplement use. In another clinical trial conducted in Germany, it was reported that consuming fiber enriched bread for only three days led to improvements in the insulin sensitivity of overweight and obese women by eight percentage points above the base level typical for such susceptible individuals. When a proper dietary intervention of such a small magnitude can have a big impact in susceptible individuals and diabetics, one can only imagine the benefits for other wise healthy individuals who spend years consuming a high fiber diet, filled with a variety of vegetables, raw fruits and whole grains on a regular basis. A high diet fiber diet is also beneficial for diabetics, as it is now proven that increasing the fiber content in food can also prevent long term complications from the disease. In at least thirty three of fifty human tests conducted on the consumption of soluble fiber and its effects, it was found that the fiber produced significant reductions in blood sugar levels of the test subjects. When people with type two diabetes were tested as a part of a clinical intervention trial that ranged from two to seventeen weeks, it was found that consuming dietary fiber actively decreased the insulin requirement in all of them. Diabetics who require regular and painful injections of insulin will appreciate this fact, they may benefit from decreasing the number of painful insulin injections they need to take by simply increasing their dietary intake of high fiber foods.
- Fiber for preventing heart disease
- A high fiber diet taken life long is the best way to protect the heart and prevent the onset of dangerous cardiac problems. This connection between a high fiber diet and a lowered risk of cardiac disorders is supported by the results from numerous clinical studies and human trials. A test sample of forty thousand male health professionals were studied in a Harvard study, during the course of the study the clinical researchers discovered that a large total dietary fiber intake over a long period of time was definitely connected to the forty per cent lower risk for coronary heart disease seen in some of the subjects, the same lowering of risk was not observed in people who consumed a low fiber diet during the course of the study.
The development of abnormally levels of cholesterol in the blood is one very strong predictor for the chances of heart disease - such an abnormality pertains to the levels of LDL or HDL in the blood. What great potential benefit of dietary soluble fiber is that soluble fiber apparently reduces the rate of absorption of cholesterol in the intestines by actively binding with dietary cholesterol and bile - rich in cholesterol - to the point where the human body begins to excrete the excess amount. This relationship between dietary fiber and cholesterol level reduction was observed during studies where oat bran and bean fiber were used as supplements in combination with a low fat diet - all the tested subjects showed a lowering in total blood cholesterol levels that ranged from eight to twenty six per cent of initial elevated levels. Similarly, in another clinical study, where subjects were given a supplement of five to ten grams of soluble fiber a day - it was found that the supplement led to a decrease in the LDL cholesterol level by about five percent of the initial elevated value. When such supplements are used, the changes occur and these beneficial effects are always seen, even in the absence of sudden changes in the level of dietary fat consumed as a part of the normal everyday diet. During one clinical human trial, test subjects were divided into two groups; one group was given a low fat diet with no fiber, while the other was given a low fat diet with a high fiber supplement. The results showed that individuals in the test group that was given a high fiber diet displayed the greatest average reduction in total cholesterol concentration at thirteen per cent compared to the other low fat only diet group, at nine percent. At the same time, people who were placed as a control group with the usual diet showed a reduction of only seven per cent in fat even with exercise. These results show that dietary changes need not always be extreme, as even without changing everything in the diet, the high fiber group still showed positive gains in terms of health.
- Fiber for bowel disorders
- Fiber adds bulk or roughage to the food, and this "roughing" up of the diet makes for bowels that are healthy and marked by ease of passage of the stool. Bowel disorders among most modern human populations shot up with the introduction of white flour in the diet; these disorders include most of the well known health problems of modern like diverticulosis, diverticulitis, painful hemorrhoids, the formation of polyps as well as colon cancer, and last but not leas IBS or irritable bowel syndrome - which have all become the bane of modern society. Clinical studies on human subjects have confirmed that the consumption of a high fiber diet, especially one rich in fruit and vegetable fibers helps prevent the onset of diverticulosis and can also lower the risk of further complications in individuals who are already suffering from the disorder. Several scientific hypotheses have attempted to explain this connection between a high fiber diet and the lowered risk for certain disorders, however, the exact way in which diets high in fiber protect against disorders such as diverticulosis is still a mystery requiring further research to unravel. Explanations offered by certain clinical scientists include the theory that dietary fiber decreases the transit time of food through the gastrointestinal tract, they also say that fiber increases the weight of stool, at the same time as it lowers the built up pressure within the colonic region. A similar explanation holds true for irritable bowel syndrome - IBS - risk and a high fiber diet. Among the various treatments suggested for the treatment of IBS includes the consumption of a high fiber diet as a supplementary part of the conventional therapy. In cases of irritable bowel syndrome, it is held that the bulk or roughage provided by the dietary fiber prevents the onset of painful spasms that are a feature often connected with IBS - fiber is believed to aid in alleviating these regular spasms. There exists a debate concerning the role that fiber plays in the prevention of colon cancer in the scientific community. In some clinical studies, research has focused on the connections that the diets of people and their health have, especially the fact that colon cancer incidences are higher in people on low-fiber diets. These protective relationship supposedly existing against colon cancer for people on a high fiber diet have not always been validated in human studies. Indeed, consuming high fiber diets will not always prevent the onset of colon cancer or polyps - as these disorders have other causes as well. However, recently concluded studies have come up with results that show a daily stool weight which is greater than one hundred grams achieved through fiber intake gives a protective action against the risk of colon cancer to a substantial measure. In earlier studies, such probable relations were not accounted for and this could be the reason that such studies suggested the absence of a protective effect from an intake of dietary fiber.
- Fiber for preventing or treating constipation
- If constipation is the problem, consuming a diet high in fiber content may be ideal. Constipation and its causes or what brings it about may not be clinically well established, the symptoms are very real, however, and all diets that can boost the number of bowel movements undertaken daily help a person. Diets that can ease the passage of stool, or those diets that can increase the bulk of the stool actually passed are all considered beneficial diets as far as the treatment of constipation is concerned. Regular bowel movements are aided by the consumption of both soluble as well as insoluble fibers as part of the regular diet. However, patients affected by constipation tend to make regular use of popular over the counter high fiber supplements to ease the symptoms and treat the disorder. The bad news is that most of these supplements sold in the market provide only soluble fiber and do not contain the other fiber component. Many clinical studies have supported the view that a combined diet of soluble and insoluble fiber is very effective in alleviating constipation, however, diets of this nature tend to be effective only when an adequate fluid intake is maintained - drinking large amounts of water is a very good idea. It is known that the constipation can be aggravated by consuming high amounts of fiber, if these are consumed without lots of fluids - therefore, care must be taken. Constipation is, therefore, ideally treated by using large amounts of water to wash down foods high in both soluble and insoluble fibers.
Sources of fiber
Insoluble dietary fibers are found in high amounts in all types of whole grains. Rich sources of insoluble dietary fiber along with some soluble fibers include oats and barley, beans, as well as psyllium, and some commonly found vegetables and fruits -though fruits juices tend to be poor in fiber content. The flaxseed is the richest source of lignan, but flaxseed oil is not rich in this substance - even though the label on products sold in the market may claim otherwise.
Deficiencies and susceptibility
Dietary fiber deficiency seems to affect almost everyone. Modern diets that predominantly consists of processed foods with a lot of white flour, white rice, and fruit juices all contribute to this state of affairs, more so as the consumption of fresh raw vegetables, whole raw fruits and unrefined or whole grains are on the decline everywhere. Processed food seems to dominate the supermarkets and many of the whole wheat products sold in the stores contain mostly white flour. The best way to ensure that one eliminates an excess of white flour from the diet is to read product labels with care and to avoid "flour" and "unbleached flour," both of which are essentially white flour. Dietary fiber is also lacking in the majority of junk foods sold at so many fast food places. Diets that are low in dietary fibers make people susceptible to the diseases that were discussed before, and increase the risk of colon and breast cancers as well.
Dieticians and nutritionist calculate that the average western diet provides about ten grams of dietary fiber per day to a person. This level of consumption is low compared to the so called primitive diet of older societies, where dietary fiber consumption can be about forty to sixty grams of fiber every day per person. It is obvious that most modern diets in the west lack sufficient fiber, therefore, boosting the total fiber intake to the level of the "primitive" diets is not only desirable, but may be the healthiest choice for all concerned.
Side effects and cautions
Although certain people may develop some allergic reactions to certain high fiber foods in the diet - the allergic response is mostly to wheat - the major effect of a high fiber diet is a great improvement in the health of the person. High fiber diets are the cause of health problems in a minuscule percentage of the population - who may already be genetically predisposed to allergic reactions. Examples of a high fiber food include all kinds of beans; this common food is an excellent source of soluble fiber, as well as many kinds of special sugars that are often poorly digested in the body, leading to the production of excess abdominal gas and consequent bloating. This problem can be significantly reduced by consuming certain special enzyme products that are now available in most supermarkets - these products improve the digestion of these sugars and avid the production of excess gas.
Dietary fiber also tends to reduce the rate of absorption of most minerals in the food. The consumption of multi-mineral supplements can overcome this effect to some extent, though such supplements must not be taken along with a high-fiber meal to avoid inhibition of mineral uptake in the stomach.
The insoluble dietary fiber found in bran, tends to reduce the rate of absorption of the essential mineral calcium, to bring about the fall of urinary calcium levels. This creates excess calcium accumulation leading to kidney stones; this eventuality may sometimes be prevented by the simple expedient of incorporating about half an ounce of dietary bran in the diet every day. The advice of a nutritionally oriented doctor is mandatory for all persons who want to use supplements of dietary bran, this precautionary consultation is required as some people may not be absorbing enough calcium in the stomach - this include some individuals already affected by kidney stones. Such individuals may be affected by a deficiency of essential calcium if they supplement with bran over any length of time.