Psyllium, but not methylcellulose or calcium polycarbophil, reduced LDL cholesteral levels in mild-to-moderate hypercholesterolemia
ACP J Club. 1991 Nov-Dec;115:86. doi:10.7326/ACPJC-1991-115-3-086
Anderson JW, Floore TL, Geil PB, O'Neal DS, Balm TK. Hypocholesterolemic effects of different bulkforming hydrophilic fibers as adjuncts to dietary therapy in mild to moderate hypercholesterolemia. Arch Intern Med. 1991 Aug;151:1597-602.
To evaluate the relative effectiveness of psyllium, methylcellulose, calcium polycarbophil, and placebo as adjuncts to the American Heart Association (AHA) step-1 diet in reducing mild-to-moderate hypercholesterolemia.
Randomized, controlled trial of 8 weeks duration, with randomization preceded by an 8-week, diet-only period.
Recruitment was from community cholesterol screenings.
163 men and women (age range, 30 to 70 y) were recruited into the diet phase. Serum total cholesterol (TC) ranged from 5.17 to 7.76 mmol/L (200 to 300 mg/dL), with serum triglyceride levels < 3.39 mmol/L (300 mg/dL). Exclusion criteria were coexisting serious disease; allergy to the study substances; and therapeutic use of substances affecting lipid levels. The 117 participants who complied with the diet and fiber-intake limit and met lipid-level criteria were randomized. 90% completed the study.
Patients were allocated to psyllium (Metamucil, powder), 3.4 g before meals (n = 27 ); methylcellulose (Citrucel, powder), 2.0 g before meals (n = 28); calcium polycarbophil (Fibercon, tablet), 1.25 g before meals and at bedtime (n = 25 ); or placebo (microcrystalline cellulose as powder or tablet), 3.4 g or 1.0 g before meals (n = 25). The fiber products were taken with 240 mL water. The doses chosen were the maximum recommended.
Main outcome measures
Fasting serum-lipid measurements.
The groups were similar in body weight, lipid profiles, and dietary intake at randomization. Mean daily cholesterol intakes ranged from 190 mg/d to 225 mg/d, and daily fat content from 30% to 33% of total calories. Low-density lipoprotein cholesterol (LDLC) levels decreased by 13.4% in the psyllium group compared with a reduction of 4.6% in the placebo group (P = 0.02). Supplements and placebo did not differ with respect to changes in TC, high-density lipoprotein cholesterol, triglycerides, or body weight. Between 17% (methyllcellulose group) and 25% (psyllium group) of participants reported mild gastrointestinal side effects, headache, or rash.
Compared with placebo, psyllium as an adjunct to diet was effective in reducing LDLC but not other lipid factors in persons with mild-to-moderate hypercholesterolemia. Methylcellulose and polycarbophil were no more effective than placebo in modifying participants' lipid profiles.
Source of funding: Procter & Gamble Co.
Address for article reprint: Dr. J. W. Anderson, Veterans Affairs Medical Center, Cooper Drive (111C), Lexington, KY 40511, USA.
This study is one of several funded by the Procter and Gamble Company that explore the effects of psyllium supplementation on lipid levels. Previous studies of persons consuming unmodified diets containing approximately 40% of daily calories as fat produced mean reductions of 11 % in TC and 18% in LDLC for psyllium (10.2 g/d) compared with placebo (1). In the current study, participants on an AHA step-1 diet had a significant decrease in LDLC (9%) with psyllium supplementation compared with placebo. The groups using less soluble fiber supplements had no significant changes in lipid levels. Because dietary fat content was low and unchanged for all participants over the course of the study, the mechanism for LDLC lowering could not have simply been that fiber replaced bacon and eggs at breakfast.
Larger doses of 10.2 g twice a day have not been shown to have greater effects in lowering TC or LDLC compared with diet only (2). The maximum decrease in LDLC with psyllium supplementation generally occurs at 8 weeks.
These reductions in LDLC with psyllium are similar to reductions with cholestyramine and gemfibrozil, and half the reduction seen with low-dose lovastatin. The cost of psyllium, especially the generic form, is significantly less than that for these medications, and the side effects of psyllium have been generally minimal and transient.
The use of psyllium can be recommended if diet changes are inadequate to lower LDLC. Because only 80% of persons taking psyllium had reductions in LDLC, an 8-week trial should be done after an AHA diet has produced its maximal effect to confirm that taking a fiber supplement will have an appreciable additional effect.
Donald A. Smith, MD, MPH
Mount Sinai Medical CenterNew York, New York, USA