Our proprietary “Star-Rating” system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.
For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.
3 StarsReliable and relatively consistent scientific data showing a substantial health benefit.
2 StarsContradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1 StarFor an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.
This supplement has been used in connection with the following health conditions:
20 grams daily, plus extra fluids
A fiber supplement may improve constipation related to diverticular disease.
In people with diverticular disease, a fiber supplement may improve constipation. The results of double-blind of fiber supplementation for diverticular disease have been mixed. One study1 demonstrated a beneficial effect of fiber supplementation in people who suffered from abdominal pain and pain with bowel movements; whereas a second study2 indicated no improvement in these symptoms following fiber supplementation. Nevertheless, long-term fiber supplementation may protect against the complications of diverticular disease.3
Type 1 Diabetes
30 grams daily
Taking fiber supplements may help to stabilize your blood sugar.
When taken with meals, high-fiber supplements such as guar gum reduced the rise in blood sugar following meals in people with type 1 diabetes.4, 5 More research is needed to determine if regular use of fiber supplements benefits long-term blood sugar control in type 1 diabetes.
Type 2 Diabetes
Talk to your doctor
Taking fiber supplements may help to stabilize your blood sugar.
High-fiber supplements, such as psyllium,6 guar gum (found in cluster beans),7 pectin (from fruit),8 oat bran,9 and glucomannan,10, 11 have improved glucose tolerance in some studies. Positive results have also been reported with the consumption of 1 to 3 ounces of powdered fenugreek seeds per day.12, 13 A review of the research revealed that the extent to which moderate amounts of fiber help people with diabetes in the long term is still unknown, and the lack of many long-term studies has led some researchers to question the importance of fiber in improving diabetes.14 Nonetheless, most doctors advise people with diabetes to eat a diet high in fiber. Focus should be placed on fruits, vegetables, seeds, oats, and whole-grain products.
Adults: 20 grams daily soluable fiber; for young children: 6.5 grams daily soy fiber
While fiber from dietary or herbal sources is often useful for constipation, it may also play a role in alleviating diarrhea.
While fiber from dietary or herbal sources is often useful for constipation, it may also play a role in alleviating diarrhea.15, 16
5 to 7 grams daily
Several trials have shown that fiber supplementation from a variety of sources accelerated weight loss in people who were following a low-calorie diet.
Fiber supplements are one way to add fiber to a weight-loss diet. Several trials have shown that supplementation with fiber from a variety of sources accelerated weight loss in people who were following a low-calorie diet.17, 18, 19, 20 Other researchers found, however, that fiber supplements had no effect on body weight, even though they resulted in a reduction in food intake.21
Irritable Bowel Syndrome
Refer to label instructions
Supplementing with fiber may help you find the right balance of regularity without episodes of diarrhea.
Limited research has suggested that fiber might help people with IBS.22, 23 However, most studies find that IBS sufferers do not benefit by adding wheat bran to their diets,24, 25, 26, 27 and some people feel worse as a result of wheat bran supplementation.28 The lack of positive response to wheat bran may result from a wheat sensitivity,29 which is one of the most common triggers for food sensitivity in people with IBS.30 Rye, brown rice, oatmeal, barley, vegetables, and psyllium husks are good sources of fiber and are less likely to trigger food sensitivities than is wheat bran. Except for psyllium, little is known about the effect of these other fibers in people with IBS.
How It Works
How to Use It
Western diets generally provide approximately 10 grams of fiber per day. People in less-developed countries consume 40 to 60 grams per day. Increasing fiber intake to the amounts found in such diets may be desirable.
Where to Find It
Whole grains are particularly high in insoluble fiber. Oats, barley, beans, fruit (but not fruit juice), psyllium, chia seed, and some vegetables contain significant amounts of both forms of fiber and are the best sources of soluble fiber. The best source of lignan, by far, is flaxseed (not flaxseed oil, regardless of packaging claims to the contrary).
Most people who consume a typical Western diet are fiber-deficient. Eating white flour, white rice, and fruit juice (as opposed to whole fruit) all contribute to this problem. Many so-called wheat products contain mostly white flour. Read labels and avoid “flour” and “unbleached flour,” both of which are simply white flour. Junk food is also fiber-depleted. The diseases listed above are more likely to occur with low-fiber diets.
The benefits of eating whole grains are largely derived from the beneficial constituents present in the outer layers of the grains, which are stripped away in making white flour and white rice. Preliminary research has found that women who ate mostly whole grains had a lower mortality rate than women who ate a comparable amount of refined grains.31
Interactions with Supplements, Foods, & Other Compounds
Fiber reduces the absorption of many minerals. However, high-fiber diets also tend to be high in minerals, so the consumption of a high-fiber diet does not appear to impair mineral status. However, logic suggests that calcium, magnesium and multimineral supplements should not be taken at the same time as a fiber supplement.
Bran, which contains insoluble fiber, reduces the absorption of calcium enough to cause urinary calcium to fall.32 In one study, supplementation with 10 grams of rice bran twice a day reduced the recurrence rate of kidney stones by nearly 90% in recurrent stone formers.33 However, it is not known whether other types of bran would have the same effect. Before supplementing with bran, people should check with a doctor, because some people—even a few with kidney stones—do not absorb enough calcium. For those people, supplementing with bran might deprive them of much-needed calcium.
Soluble fiber is found primarily in fruit, beans, and oats, but it is also available separately as pectin, oat bran, and glucomannan. Two sources of soluble fiber—pectin (found in fruit) and oat bran (a component of oatmeal also available by itself)—have been reported to interact with lovastatin.36 The fiber from these two sources appears to bind the drug in the gastrointestinal tract and reduce absorption of the drug as a consequence. People taking this drug should avoid concentrated intake of soluble fiber, as taking lovastatin with a high soluble-fiber diet leads to reduced drug effectiveness.
Propoxyphene may cause gastrointestinal (GI) upset. Propoxyphene-containing products may be taken with food to reduce or prevent GI upset.37 A common side effect of narcotic analgesics is constipation.38 Increasing dietary fiber (especially vegetables and whole-grain foods) and water intake can ease constipation.
The Drug-Nutrient Interactions table may not include every possible interaction. Taking medicines with meals, on an empty stomach, or with alcohol may influence their effects. For details, refer to the manufacturers’ package information as these are not covered in this table. If you take medications, always discuss the potential risks and benefits of adding a supplement with your doctor or pharmacist.
The most common adverse effects of dietary fiber are minor gastrointestinal symptoms. There have been several reports of allergic reactions to psyllium. In rare cases, obstruction of the large or small intestine has occurred in people consuming wheat bran or bran cereal.
Beans, a good source of soluble fiber, also contain special sugars that are often poorly digested, leading to gas.
People with scleroderma (systemic sclerosis) should consult a doctor before taking fiber supplements or eating high-fiber diets. Although a gradual introduction of fiber in the diet may improve bowel symptoms in some cases, there have been several reports of people with scleroderma developing severe constipation and even bowel obstruction requiring hospitalization after fiber supplementation.39
1. Smits BJ, Whitehead AM, Prescott P. Lactulose in the treatment of symptomatic diverticular disease: a comparative study with high-fibre diet. Br J Clin Pract 1990;44:314-8.
2. Ornstein MH, Littlewood ER, Baird IM, et al. Are fibre supplements really necessary in diverticular disease of the colon? A controlled clinical trial. Br Med J (Clin Res Ed) 1981;25:1353-6.
3. Leahy AL, Ellis RM, Quill DS, Peel AL. High fibre diet in symptomatic diverticular disease of the colon. Ann R Coll Surg Engl 1985;67:173-4.
4. Vuorinen-Markkola H, Sinisalo M, Koivisto VA. Guar gum in insulin-dependent diabetes: effects on glycemic control and serum lipoproteins. Am J Clin Nutr 1992;56:1056-60.
5. Ebeling P, Yki-Jarvinen H, Aro A, et al. Glucose and lipid metabolism and insulin sensitivity in type 1 diabetes: the effect of guar gum. Am J Clin Nutr 1988;48:98-103.
6. Rodriguez-Moran M, Guerrero-Romero F, Lazcano-Burciaga G. Lipid- and glucose-lowering efficacy of plantago psyllium in type II diabetes. J Diabetes Complications 1998;12:273-8.
7. Landin K, Holm G, Tengborn L, Smith U. Guar gum improves insulin sensitivity, blood lipids, blood pressure, and fibrinolysis in healthy men. Am J Clin Nutr 1992;56:1061-5.
8. Schwartz SE, Levine RA, Weinstock RS, et al. Sustained pectin ingestion: effect on gastric emptying and glucose tolerance in non-insulin-dependent diabetic patients. Am J Clin Nutr 1988;48:1413-7.
9. Hallfrisch J, Scholfield DJ, Behall KM. Diets containing soluble oat extracts improve glucose and insulin responses of moderately hypercholesterolemic men and women. Am J Clin Nutr 1995;61:379-84.
10. Doi K, Matsuura M, Kawara A, Baba S. Treatment of diabetes with glucomannan (konjac mannan). Lancet 1979;1:987-8 [letter].
11. Vuksan V, Sievenpiper JL, Owen R, et al. Beneficial effects of viscous dietary fiber from Konjac-mannan in subjects with the insulin resistance syndrome: results of a controlled metabolic trial. Diabetes Care 2000;23:9-14.
12. Sharma RD, Raghuram TC. Hypoglycaemic effect of fenugreek seeds in non-insulin dependent diabetic subjects. Nutr Res 1990;10:731-9.
13. Raghuram TC, Sharma RD, Sivakumar B, Sahay BK. Effect of fenugreek seeds on intravenous glucose disposition in non-insulin dependent diabetic patients. Phytother Res 1994;8:83-6.
14. Nuttall FW. Dietary fiber in the management of diabetes. Diabetes 1993;42:503-8.
15. Eherer AH, Porter J, Fordtran JS. Effect of psyllium, calcium polycarbophil, and wheat bran on secretory diarrhea induced by phenolphthalein. Gastroenterol 1993;104:1007-12.
16. Quartarone G. Role of PHGG as a dietary fiber: a review article. Minerva Gastroenterol Dietol 2013 Dec;59:329-40.
17. Marquette CJ Jr. Effects of bulk producing tablets on hunger intensity in dieting patients. Obes Bariatr Med 1976;5:84-8.
18. Rossner S, von Zweigbergk D, Ohlin A, Ryttig K. Weight reduction with dietary fibre supplements. Acta Med Scand 1987;222:83-8.
19. Ryttig KR, Tellnes G, Haegh L, et al. A dietary fibre supplement and weight maintenance after weight reduction: a randomized, double-blind, placebo-controlled long-term trial. Int J Obes 1989;13:165-71.
20. Solum TT, Ryttig KR, Solum E, Larsen S. The influence of a high-fibre diet on body weight, serum lipids and blood pressure in slightly overweight persons. A randomized, double-blind, placebo-controlled investigation with diet and fibre tablets (DumoVital). Int J Obes 1987;11 Suppl 1:67-71.
21. Hylander B, Rössner S. Effects of dietary fiber intake before meals on weight loss and hunger in a weight-reducing club. Acta Med Scand 1983;213:217-20.
22. Manning AP, Heaton KW, Harvey RF, Uglow P. Wheat fibre and irritable bowel syndrome. Lancet 1977;ii:417-8.
23. Hotz J, Plein K. Effectiveness of plantago seed husks in comparison with wheat bran no stool frequency and manifestations of irritable colon syndrome with constipation. Med Klin 1994;89:645-51.
24. Cann PA, Read NW, Holdsworth CD. What is the benefit of coarse wheat bran in patients with irritable bowel syndrome? Gut 1984;25:168-73.
25. Arffmann S, Andersen JR, Hegnhoj J, et al. The effect of coarse wheat bran in the irritable bowel syndrome. A double-blind cross-over study. Scand J Gastroenterol 1985;20:295-8.
26. Soloft J, Krag B, Gudmand-Hoyer E, et al. A double-blind trial of the effect of wheat bran on symptoms of irritable bowel syndrome. Lancet 1976;i:270-3.
27. Lucey MR, Clark ML, Lowndes J, Dawson AM. Is bran efficacious in irritable bowel syndrome? A double blind placebo controlled crossover study. Gut 1987;28:221-5.
28. Francis CY, Whorwell PJ. Bran and irritable bowel syndrome: time for reappraisal. Lancet 1994;344:39-40.
29. Gaby AR. Commentary. Nutrition and Healing 1996;Feb:1,10-1 [review].
30. Niec AM, Frankum B, Talley NJ. Are adverse food reactions linked to irritable bowel syndrome? Am J Gastroenterol 1998;93:2184-90 [review].
31. Jacobs DR, Pereira MA, Meyer KA, Kushi LH. Fiber from whole grains, but not refined grains, is inversely associated with all-cause mortality in older women: the Iowa women's health study. J Am Coll Nutr 2000;19(3 Suppl):326S-30S.
32. Shah PJR. Unprocessed bran and its effect on urinary calcium excretion in idiopathic hypercalciuria. Br Med J 1980;281:426.
33. Ebisuno S, Morimoto S, Yoshida T, et al. Rice-bran treatment for calcium stone formers with idiopathic hypercalciuria. Brit J Urol 1986;58:592-5.
34. Tylenol with Codeine (Codeine and acetaminophen) tablet [package insert]. Ortho-McNeil Pharmaceutical, Inc. Rarition, New Jersey http://www.losepain.com/pdf/tylenol.pdf Accessed September 12, 2011
35. Threlkeld DS, ed. Diuretics and Cardiovasculars, Calcium Channel Blocking Agents. In Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Nov 1992, 150-b.
36. Richter W, Jacob B, Schwandt P. Interaction between fibre and lovastatin. Lancet 1991;338:706 [letter].
37. Threlkeld DS, ed. Central Nervous System Drugs, Narcotic Agonist Analgesics. In Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Feb 1990, 242-3v.
38. Threlkeld DS, ed. Central Nervous System Drugs, Narcotic Agonist Analgesics. In Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Feb 1990, 242-3v.
39. Gough A, Sheeran T, Bacon P, Emery P. Dietary advice in systemic sclerosis: the dangers of a high fibre diet. Ann Rheum Dis 1998;57:641-2.
The information presented in Aisle7 is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2015.
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