Psyllium hydrophilic mucilloid reduced total cholesterol and LDL cholesterol levels in mild-to-moderate hypercholesterolemia
ACP J Club. 1991 Jan-Feb;114:2. doi:10.7326/ACPJC-1991-114-1-002
Levin EG, Miller VT, Muesing RA, et al. Comparison of psyllium hydrophilic mucilloid and cellulose as adjuncts to a prudent diet in the treatment of mild to moderate hypercholesterolemia. Arch Intern Med. 1990;150:1822-7.
To evaluate the efficacy and safety of psyllium hydrophilic mucilloid as an adjunct to a prudent diet in lowering plasma lipid and lipoprotein levels in patients with mild-to-moderate primary hypercholesterolemia when compared with placebo (cellulose).
Randomized, double-blind, placebo-controlled trial of 16 weeks duration.
George Washington University Medical Center.
96 patients with mild-to-moderate primary hypercholesterolemia volunteered to participate. Inclusion criteria were age between 21 and 70 years, plasma cholesterol levels > 5.17 mmol/L and < 90th percentile for age and sex, plasma triglyceride levels < 3.39 mmol/L, and > body weight < 30% above ideal. 34 patients withdrew (n = 14) or were excluded (n = 20) during the 8-week diet stabilization period.
After diet stabilization, patients were randomly assigned to psyllium hydrophilic mucilloid (5.1 g of sugar-free, orange-flavored Metamucil [Procter & Gamble Co.] containing 79% psyllium hydrophilic mucilloid to be taken twice daily) (n = 30) or placebo (5.1 g cellulose to be taken twice daily) (n = 28) for 16 weeks.
Main outcome measures
Fasting total plasma cholesterol, low-density lipoprotein (LDL) cholesterol (derived and measured), high-density lipoprotein (HDL) cholesterol, and triglyceride levels.
At the end of the 16-week treatment period, psyllium reduced total cholesterol by 5.6% (P = 0.01) and LDL cholesterol by 8.6% (P < 0.05) compared with a 0.1% increase and 2.2% decrease with placebo. HDL cholesterol increased by 1.5% in the psyllium group and by 8.2% in the placebo group above baseline. Consequently, the ratio of LDL cholesterol/HDL cholesterol decreased similarly in both groups. Triglyceride levels did not change. Patient compliance was > 95%. 3 patients (1 receiving psyllium and 2 receiving placebo) withdrew from the study because of gastrointestinal complaints.
Psyllium hydrophilic mucilloid taken twice daily as an adjunct to a prudent diet provided sustained reductions in total cholesterol and LDL cholesterol levels for up to 4 months in highly compliant patients with mild-to-moderate hypercholesterolemia. Psyllium has few clinically significant adverse effects, but its long-term safety and benefits are unknown.
Source of funding: In part, The Procter and Gamble Company.
Address for article reprint: Dr. J. C. La-Rosa, The George Washington University Medical Center, 901 23rd Street NW, Washington, DC 20037, USA.
Although psyllium twice daily reduces total cholesterol and LDL cholesterol in highly compliant patients with mild-to-moderate hypercholesterolemia, its effectiveness in routine clinical practice, where compliance with prescribed therapy is often problematic, is unclear. It is also unclear whether psyllium favorably alters the blood lipids profile compared with placebo (cellulose) because both reduced the ratio of LDL cholesterol to HDL cholesterol to a similar extent. The debate here centers on whether the reduction in coronary heart disease risk is related to a reduction in atherogenic LDL cholesterol, an increase in antiatherogenic HDL cholesterol, the sum of the fall in LDL cholesterol and rise in HDL cholesterol, or some interactive relation between LDL and HDL cholesterol. If a favorable effect on HDL cholesterol is a critical element in reducing risk for coronary heart disease, psyllium would not provide a benefit compared with placebo.
4 months of psyllium and placebo (bulk cellulose fiber) treatment significantly reduced serum ferritin levels. More prolonged therapy without the co-administration of iron would likely produce iron-deficiency anemia. Supplemental iron would increase the complexity of the regimen, the risk for adverse effects, and the cost of treatment.
Further study of the use of psyllium in the management of hypercholesterolemia is required before it can be recommended for widespread use.
Alexander G. Logan, MD
Mount Sinai HospitalToronto, Ontario, Canada