Fiber

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References

Bassotti G, Calcara C, Annese V, Fiorella S, Roselli P, Morelli A. Nifedipine and verapamil inhibit the sigmoid colon myoelectric response to eating in healthy volunteers. Dis Colon Rectum 1998 Mar;41(3):377-380.
Abstract: BACKGROUND: Constipation is not an infrequent side effect complained of by patients taking calcium channel blockers. This effect may reduce patients' compliance and yield potentially serious consequences. However, the underlying mechanisms for constipation caused by such compounds are not known. AIMS: The purpose of the present study was to assess the effects of nifedipine and verapamil on the sigmoid myoelectric response to eating, a physiologic test of colonic motor function. SUBJECTS AND METHODS: Nine healthy male volunteers with no previous abdominal surgery were recruited for the study and underwent three paired studies at two-week intervals. Myoelectric sigmoid activity was recorded by means of two clip electrodes introduced within the viscus without preparation for 30 minutes basally and 90 minutes postprandially. Each study was preceded by placebo, nifedipine (20 mg), or verapamil (120 mg). RESULTS: Analysis of the tracings revealed that nifedipine strongly inhibited the sigmoid myoelectric response to the meal. This response was also significantly reduced in those taking verapamil compared with the placebo group, although to a much lesser extent than in those taking nifedipine. CONCLUSIONS: We conclude that constipation as a result of some calcium channel blockers may be caused by inhibition of colonic motor activity by nifedipine and, to a lesser extent, by verapamil. The latter compound probably displays other mechanisms (reduced colonic transit, increased water absorption) also responsible for this side effect.

Bruttomesso D, Biolo G, Inchiostro S, Fongher C, Briani G, Duner E, Marescotti MC, Iori E, Tiengo A, Tessari P. No effects of high-fiber diets on metabolic control and insulin-sensitivity in type 1 diabetic subjects. Diabetes Res Clin Pract 1991 Aug;13(1-2):15-21.
Abstract: The metabolic effects of a three-month treatment with a high-fiber diet (15 grams of guar-gum added to a standard diet) were investigated in seven type 1 diabetic subjects, with a moderately poor metabolic control. HbA1c levels, daily insulin requirement, cholesterol, triglyceride, amino acid and intermediate metabolite concentrations were evaluated before and following the high fiber diet, both in the postabsorptive state at euglycemia and during a euglycemic, hyperinsulinemic, hyperaminoacidemic clamp. Insulin-mediated glucose utilization, an index of insulin-sensitivity, was also measured during the clamp. Following the diet, no differences in HbA1c levels (7.6 +/- 0.7%----7.3 +/- 0.6%), daily insulin requirement (50 +/- 5----51 +/- 3 U/d), triglyceride, amino acid and intermediary metabolite concentrations in the basal, euglycemic state, were observed. Only cholesterol concentrations decreased significantly (from 165 +/- 12 to 142 +/- 12 mg/dl, P less than 0.01) after the diet. During the clamp, the concentrations of all measured substrates were comparable before and after high fiber treatment. Insulin-mediated glucose disposal was also unchanged by guar-gum treatment. Patients' body weights were not modified by the diet. In conclusion, our study shows that a high fiber diet, obtained with the addition of 15 grams of guar-gum to a standard diet, is of no benefit to IDDM either as regards the metabolic control or insulin sensitivity. Only cholesterol levels were decreased. Therefore, the costs and benefits of these diets in the treatment of IDDM should be reconsidered.

Briani G, Bruttomesso D, Bilardo G, Giorato C, Duner E, Ion E, Sgnaolin E, Pedrini P, Tiengo A. Guar-Enriched Pasta and Guar Gum in the Dietary Treatment of Type II Diabetes. Phytother Res 1987 1:177-179.

Buist RA. Drug-nutrient interactions - an overview. Intl Clin Nutr Rev 1984;4(3):114. (Review)

Fairchild RM, Ellis PR, Byrne AJ, Luzio SD, Mir MA. A new breakfast cereal containing guar gum reduces postprandial plasma glucose and insulin concentrations in normal-weight human subjects. Br J Nutr 1996 Jul;76(1):63-73.
Abstract: A new guar-containing wheatflake product was developed to assess its effect on carbohydrate tolerance in normal-weight, healthy subjects. The extruded wheatflake breakfast cereals containing 0 (control) or approximately 90 g guar gum/kg DM were fed to ten fasting, normal-weight, healthy subjects using a repeated measures design. The meals were similar in energy (approximately 1.8 MJ), available carbohydrate (78 g), protein (15 g) and fat (5.4 g) content. The guar gum content of the test meals was 6.3 g. Venous blood samples were taken fasting and at 15, 30, 45, 60, 90, 120, 150 and 240 min after commencing each breakfast and analysed for plasma glucose, insulin and C-peptide. The guar wheatflake meal produced a significant main effect for glucose and insulin at 0-60 min and 0-240 min time intervals respectively, but not for the C-peptide levels compared with the control meal. Significant reductions in postprandial glucose and insulin responses were seen following the guar wheatflake meal compared with the control meal at 15 and 60 min (glucose) and 15, 60, 90 and 120 min (insulin). The 60 and 120 min areas under the curve for glucose and insulin were significantly reduced by the guar gum meal, as was the 240 min area under the curve for insulin. Thus, it can be concluded that the use of a severe method of heat extrusion to produce guar wheatflakes does not diminish the physiological activity of the guar gum.

Gatenby SJ, Ellis PR, Morgan LM, Judd PA. Effect of partially depolymerized guar gum on acute metabolic variables in patients with non-insulin-dependent diabetes. Diabet Med 1996 Apr;13(4):358-364.
Abstract: Fourteen patients with non-insulin-dependent diabetes (NIDDM) attended the study centre on 4 mornings separated by at least 3 days, to receive in random order 75 g carbohydrate breakfast meals of control or guar breads with jam and butter. Guar gum flours of low, medium, and high molecular weight (MW) were incorporated into wheat bread rolls to provide 7.6 g guar per meal. Venous blood samples were taken via an indwelling cannula in a forearm vein at fasting and at eight postprandial times and then analysed for blood glucose, plasma insulin, C-peptide, and gastric inhibitory polypeptide (GIP). Guar gum bread significantly reduced the postprandial rise in blood glucose, plasma insulin, and, except for bread containing low MW guar gum, plasma GIP levels compared to the control. Thus, the partial depolymerization of guar gum does not diminish its physiological activity. No reductions in postprandial plasma C-peptide levels were seen after any of the guar bread meals. This suggests that guar gum attenuates the insulin concentration in peripheral venous blood in patients with NIDDM by increasing the hepatic extraction of insulin.

Holt GA. Food and Drug Interactions. Chicago: Precept Press, 1998, 274-275.

Huupponen R, Seppala P, Iisalo E. Effect of guar gum, a fibre preparation, on digoxin and penicillin absorption in man. Eur J Clin Pharmacol 1984;26(2):279-281.
Abstract: The effect of guar gum on the absorption of digoxin and phenoxymethyl penicillin was studied in a double blind study in 10 healthy volunteers. Guar gum reduced serum digoxin concentration during the early absorption period, but a similar amount of digoxin was found in 24 h urine whether given with or without guar gum. Both the peak penicillin concentration and the area under the serum curve were significantly reduced by the gum.

Johnson BF, Rodin SM, Hoch K, Shekar V. The effect of dietary fiber on the bioavailability of digoxin in capsules. J Clin Pharmacol 1987 Jul;27(7):487-490.
Abstract: Sixteen healthy volunteers were regularly given 0.4 mg of digoxin daily as two capsules with breakfast. After ten days during which breakfast was supplemented with 11 g of bran fiber, steady-state predose mean serum digoxin was lower (0.89 +/- 0.19 versus 0.84 +/- 0.18 ng/mL, P less than .05) and mean 24-hour area under curve determination was lower (30.5 +/- 6.1 versus 28.4 +/- 6.0 ng X hr/mL, P less than .05) than during the control period without bran. Height and time of peak serum digoxin, and 24-hour urinary digoxin were not significantly different. The 6 to 7% reduction in digoxin absorption from capsules is less than that reported from tablets and is probably clinically unimportant.

Krevsky B, Maurer AH, Niewiarowski T, Cohen S. Effect of verapamil on human intestinal transit. Dig Dis Sci 1992 Jun;37(6):919-924.
Abstract: Although constipation is a well-known side effect of calcium channel blockers such as verapamil, this side effect has not been evaluated in a quantitative manner. In a double-blind, randomized, crossover trial, the effect of verapamil (240 mg/day) was compared to placebo in 15 normal male volunteers. Subjects recorded their bowel movements and any side effects. Scintigraphy was used to quantitate gastric emptying, small intestinal transit, and colonic transit. In the study period of four days, verapamil did not change the frequency, consistency, or passage of bowel movements. A significantly increased number of side effects was noted during verapamil treatment--notably abdominal pain and dry mouth. The slope of gastric emptying was not significantly different for verapamil (0.012 +/- 0.02) than for placebo (0.013 +/- 0.001). Distal ileum filling was also not different for verapamil (0.41 +/- 0.13%/min) than placebo (0.33 +/- 0.05%/min). Progression of the colonic geometric center was significantly delayed at 48 hr by verapamil (5.2 +/- 0.4 vs 6.2 +/- 0.23; P less than 0.01). This study suggests that the constipating effect of verapamil is due to a delay of colonic transit and not due to an effect on upper gastrointestinal transit.

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 Dec;56(6):1061-1065.
Abstract: A double-blind, placebo-controlled, cross-over study was carried out in 25 healthy, nonobese middle-aged men to test the effect of guar gum on glucose and lipid metabolism, blood pressure, and fibrinolysis. Ten grams guar or placebo granulate was given three times a day for 6 wk with a 2-wk run-in before and a wash-out period after. Decreases in fasting blood glucose (P < 0.001), cholesterol (P < 0.001), triglycerides (P < 0.05), plasminogen activator inhibitor-1 activity (P < 0.01), systolic blood pressure (P < 0.01), and diastolic blood pressure (P < 0.001) were seen during guar treatment when compared with placebo. Insulin sensitivity, measured with the euglycemic-clamp technique, increased (P < 0.01), adipose tissue-glucose uptake measured in vitro increased (P < 0.001), and 24-h urinary excretion of sodium and potassium increased (P < 0.001) during guar treatment. Fasting plasma insulin, renin, aldosterone, and fibrinogen concentrations as well as skeletal-muscle electrolytes, urinary catecholamines, and body weight remained unaltered. These findings support a role for guar in the treatment of the metabolic syndrome in which insulin resistance seems to play a pivotal role.

Perlman BB. Interaction between lithium salts and ispaghula husk. Lancet 1990 Feb 17;335(8686):416. (Letter)

Pronsky, Zaneta. Powers and Moore's Food-Medications Interactions. Ninth Edition. Food-Medication Interactions. Pottstown, PA, 1991.

Richter W, Jacob B, Schwandt P. Interaction between fibre and lovastatin. Lancet 1991;Sep 14;338(8768):706. (Letter)

Robinson C, Weigly E. Basic Nutrition and Diet Therapy. New York: MacMillan, 1984.

Roe DA. Diet and Drug Interactions. New York: Van Nostrand Reinhold, 1989.

Roe DA. Drug-induced Nutritional Deficiencies. 2nd ed. Westport, CT: Avi Publishing, 1985: 158-159.

Roe DA. Risk factors in drug-induced nutritional deficiencies. In: Roe DA, Campbell T, eds. Drugs and Nutrients: The Interactive Effects. New York: Marcel Decker, 1984: 505-523.

Semple HA, Koo W, Tam YK, Ngo LY, Coutts RT. Interactions between hydralazine and oral nutrients in humans. Ther Drug Monit 1991 Jul;13(4):304-308.
Abstract: To help clarify whether food or enteral nutrients decrease hydralazine relative bioavailability, eight subjects were given oral hydralazine under four nutritional conditions: fasted (F), with a standard breakfast (SB), with a bolus of enteral nutrients (EB), and with a slow infusion of enteral nutrients administered by nasogastric tube (EI). The area under the curve and maximum concentration values were much higher under the fasted and enteral infusion conditions than under the standard breakfast or enteral bolus conditions, indicating that the absorption and/or disposition kinetics of hydralazine may be altered by food. The median (range) values for these parameters were 2,641 (385-4,747) and 87 (4.5-224) for F; 1,189 (202-1,737) and 15 (3.5-33.9) for SB; 999 (227-3,576) and 11 (2.5-50) for EB; and 3,068 (313-4,917) ng/ml/min and 113 (3.6-235) ng/ml for EI. Furthermore, the rate of nutrient administration, but not necessarily the physical form, of the nutrients appears to be a significant factor in determining the magnitude of the food effect. The nutrient interaction should be accounted for in patients receiving hydralazine and enteral nutrition concomitantly.

Spence JD, Huff MW, Heidenheim P, Viswanatha A, Munoz C, Lindsay R, Wolfe B, Mills D. Combination therapy with colestipol and psyllium mucilloid in patients with hyperlipidemia. Ann Intern Med 1995 Oct 1;123(7):493-499.
Abstract: OBJECTIVE: To test whether combining psyllium mucilloid with half the usual dose of colestipol reduces the adverse effects associated with colestipol and maintains or increases its efficacy in the treatment of hyperlipidemia. This strategy might make bile acid sequestrants, which are seldom used because they cause adverse effects such as bloating and constipation, more tolerable and less expensive. DESIGN: A randomized, parallel-group, double-blind, controlled trial. SETTING: An outpatient clinic in a tertiary care hospital. PATIENTS: 121 patients who had moderate primary hypercholesterolemia (total cholesterol level > 6 mmol/L and < 8 mmol/L; triglyceride level < 3 mmol/L) after following a low-fat diet for 1 year (National Cholesterol Education Program Step Two diet). INTERVENTION: 5 g of cellulose placebo; 5 g of colestipol; 2.5 g of colestipol plus 2.5 g of psyllium; or 5 g of psyllium three times daily before meals for 10 weeks. MAIN OUTCOME MEASURES: At baseline and at weeks 4 and 10, fasting blood lipid levels and apoprotein concentrations were measured and a quality-of-life instrument was completed. RESULTS: A combination of 2.5 g of psyllium and 2.5 g of colestipol was better tolerated than and as effective as either 5 g of colestipol alone or 5 g of psyllium alone. The combination therapy and colestipol alone did not differ significantly with respect to changes in individual lipid values. The ratio of total cholesterol to high-density lipoprotein cholesterol (HDL) was reduced by 18.2% (95% CI, 12.3% to 24%) with the combination therapy; by 10.6% (CI, 2.0% to 15.4%) with colestipol alone; by 6.1% (CI, 1.5% to 10.6%) with psyllium alone; and by 0.1% (CI, -4.8% to 7%) with placebo (P = 0.0002). Combination therapy reduced the ratio of total cholesterol to HDL significantly more than did colestipol alone or psyllium alone (P < 0.05). CONCLUSIONS: These findings suggest that adding psyllium to half the usual dose of bile acid sequestrant resins maintains the efficacy and improves the tolerability of these resins.

Stockey IH. Drug Interactions, 4th Edition, London: Pharmaceutical Press, 1996.

Threlkeld DS, ed. Diuretics and Cardiovasculars, Calcium Channel Blocking Agents. In: Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Nov 1992.

Toutoungi M, Schulz P, Widmer J, Tissot R. [Probable interaction of psyllium and lithium]. Therapie 1990 Jul-Aug;45(4):358-360. (Letter) [Article in French]

Werbach MR. Foundations of Nutritional Medicine. Tarzana, CA: Third Line Press, 1997. (Review).

Zilly W, Kuhlmann J, Kasper H, Richter E. [Effect of a fiber-rich diet on digoxin resorption]. Med Klin [Prax] 1982 Sep 10;77(19):42-48. [Article in German]
Abstract: In five female healthy volunteers the influence of dietary fiber (wheat bran or carob seed flour) on absorption of digoxin was investigated. Five minutes after ingestion of a formula diet alone or in combination with wheat bran or carob seed flour 0,8 mg beta-acetyldigoxin was given per os. The plasmaconcentration-time curve over eight hours, the area under curve and the cumulative urinary excretion were not changed significantly. It was concluded that there is no influence of dietary fiber on rate or degree of digoxin-absorption.